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bronchopulmonary-dysplasia-bpd-prevention - SUMMARY AND RECOMMENDATIONS
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●Definition– Clinically, BPD is defined as an ongoing need for supplemental oxygen and/or respiratory support at either 28 days postnatal age or 36 weeks postmenstrual age (calculator 1) in a preterm neonate with radiographic evidence of parenchymal lung disease (image 1). Various criteria are used to define BPD (table 2). (See'Terminology'above.)
●Effective interventions– Interventions that are effective for reducing the risk of bronchopulmonary dysplasia (BPD) in extremely preterm (EPT) infants (gestational age [GA] <28 weeks) who are at risk for BPD include (algorithm 1) (see'Our approach'above and'Interventions'above):
•Antenatal glucocorticoid therapy– Antenatal glucocorticoid therapy for pregnant individuals <34 weeks gestation who are at high risk for preterm delivery, which is discussed in detail separately. (See"Antenatal corticosteroid therapy for reduction of neonatal respiratory morbidity and mortality from preterm delivery".)
•Nutrition and fluid management– In all preterm infants, nutritional goals are set to provide adequate caloric intake to promote somatic and lung growth, and fluid intake is adjusted to maintain neutral or slightly negative water balance. Mother's breast milk is the preferred nutritional source, and if not available, donor breast milk is used. These issues are discussed separately. (See"Approach to enteral nutrition in the premature infant"and"Parenteral nutrition in premature infants"and"Fluid and electrolyte therapy in newborns"and"Human milk feeding and fortification of human milk for premature infants"and"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Fluid management'.)
•Oxygen targets– In preterm infants who require supplemental oxygen, target oxygen saturation (SpO2) levels are set for values between 90 and 95 percent, as discussed separately. (See"Neonatal target oxygen levels for preterm infants", section on 'Oxygen target levels'.)
•Ventilation strategies that minimize lung injury– Use of ventilation strategies that minimize lung injury, including preferential use of noninvasive modalities. The approach to mechanical ventilation in preterm infants is summarized in the table (table 3) and discussed in detail separately. (See"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Clinical approach'and"Approach to mechanical ventilation in very preterm neonates".)
•Caffeinetherapy– Earlycaffeinetherapy is routinely given to all EPT infants, as discussed separately. (See"Management of apnea of prematurity", section on 'Caffeine'.)
•Vitamin Asupplementation– The use ofvitamin Asupplementation is center-dependent. If vitamin A is available, practitioners may consider its administration to EPT infants who require ventilatory support; however, the relative benefit of vitamin A supplementation in this setting appears to be small. (See'Vitamin A'above.)
•Postnatal glucocorticoids– We donotroutinely administer postnatal systemic or inhaled glucocorticoids to prevent BPD. Systemic glucocorticoids are reserved for EPT infants who remain ventilator-dependent and/or require oxygen supplementation >50 percent at a postnatal age of two to four weeks. This is discussed in detail separately. (See"Postnatal use of glucocorticoids for prevention of bronchopulmonary dysplasia (BPD) in preterm infants".)
●Ineffective interventions– Interventions that do not appear to be effective for prevention of BPD in EPT infants include (see'Unproven interventions'above):
•Sustained lung inflation during neonatal resuscitation (see"Neonatal resuscitation in the delivery room", section on 'Sustained inflation')
•Inhaled nitric oxide (iNO) (see"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Limited role for inhaled nitric oxide')
•Late surfactant therapy (see"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Timing')
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bronchopulmonary-dysplasia-bpd-prevention - INTRODUCTION
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Bronchopulmonary dysplasia (BPD; also known as neonatal chronic lung disease [CLD]) is a major cause of respiratory illness in preterm infants. It is an important contributing factor in the increased risk of mortality and morbidity in the preterm population.
This topic will provide an overview of strategies used to prevent BPD. Other related topics include:
●(See"Antenatal corticosteroid therapy for reduction of neonatal respiratory morbidity and mortality from preterm delivery".)
●(See"Postnatal use of glucocorticoids for prevention of bronchopulmonary dysplasia (BPD) in preterm infants".)
●(See"Bronchopulmonary dysplasia (BPD): Clinical features and diagnosis".)
●(See"Bronchopulmonary dysplasia (BPD): Management and outcome".)
●(See"Complications and long-term pulmonary outcomes of bronchopulmonary dysplasia".)
●(See"Pulmonary hypertension associated with bronchopulmonary dysplasia".)
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bronchopulmonary-dysplasia-bpd-prevention - TERMINOLOGY
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●Prematurity– Different degrees of prematurity are defined by gestational age (GA), which is calculated from the first day of the mother's last period, or birth weight (BW), as summarized in the table (table 1) and discussed in detail separately. (See"Preterm birth: Definitions of prematurity, epidemiology, and risk factors for infant mortality", section on 'Definitions'.)
●BPD– BPD is a chronic lung disease characterized by disruption of pulmonary development and/or lung injury in the context of preterm birth. Clinically, BPD is defined as an ongoing need for supplemental oxygen and/or respiratory support at either 28 days postnatal age or 36 weeks postmenstrual age (calculator 1) in a preterm neonate with radiographic evidence of parenchymal lung disease (image 1). Various criteria are used to define BPD, as summarized in the (table 2) and discussed in detail separately. (see"Bronchopulmonary dysplasia (BPD): Clinical features and diagnosis", section on 'Definitions and severity of BPD').
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bronchopulmonary-dysplasia-bpd-prevention - OUR APPROACH
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The following is a summary of the strategies that we use to reduce the incidence of BPD in infants who are at risk for developing BPD. The combination of interventions addresses the multiple risk factors implicated in the pathogenesis of BPD (algorithm 1). (See"Bronchopulmonary dysplasia (BPD): Clinical features and diagnosis", section on 'Risk factors'.)
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bronchopulmonary-dysplasia-bpd-prevention - OUR APPROACH - Initial general measures
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General measures are provided to all infants who are at risk for BPD (extremely preterm [EPT] infant, gestational age <28 weeks). General measures are provided to all infants who are at risk for BPD (extremely preterm [EPT] infant, gestational age <28 weeks).
●Antenatal steroids – Antenatal glucocorticoids are appropriate for pregnant woman at 23 to 34 weeks of gestation at high risk for preterm delivery within the next seven days. This is discussed separately. (See"Antenatal corticosteroid therapy for reduction of neonatal respiratory morbidity and mortality from preterm delivery".)
●Fluid management – After the first week of life, fluid intake is generally restricted to 130 to 140 mL/kg per day to maintain neutral or slightly negative fluid balance. Fluid status and nutritional status is monitored frequently, and fluid intake modified to avoid dehydration and overhydration and to ensure adequate growth. (See"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Fluid management'.)
●Nutrition – In our centers, nutritional goals are set to provide adequate caloric intake to promote somatic and lung growth [1]. Mother's breast milk is the preferred nutritional source, and if not available, we use donor breast milk. (See"Approach to enteral nutrition in the premature infant".)
●Caffeine– We administer caffeine to all EPT infants within the first 24 hours of life. These neonates have the highest risk for BPD. (See"Management of apnea of prematurity", section on 'Caffeine'.)
●Vitamin A– One of the authors of this topic routinely uses vitamin A (if available) in ventilator-dependent extremely low birth weight (ELBW) infants (birth weight <1000 g). (See'Vitamin A'below.)
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bronchopulmonary-dysplasia-bpd-prevention - OUR APPROACH - Respiratory support
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The goal for respiratory support for infants at risk for BPD is to maintain adequate oxygenation and ventilation while minimizing respiratory intervention that may lead to lung injury. Our approach is briefly summarized here. These interventions are discussed in greater detail separately. (See The goal for respiratory support for infants at risk for BPD is to maintain adequate oxygenation and ventilation while minimizing respiratory intervention that may lead to lung injury. Our approach is briefly summarized here. These interventions are discussed in greater detail separately. (See "Respiratory distress syndrome (RDS) in preterm neonates: Management" and "Approach to mechanical ventilation in very preterm neonates" .)
●In infants who require supplemental oxygen, we set a peripheral oxygen saturation (SpO2) target range of 90 to 95 percent. (See'Ventilation strategies to minimize lung injury'below and"Neonatal target oxygen levels for preterm infants".)
●In most preterm infants, we use early positive airway pressure support (typically with continuous positive airway pressure [CPAP]). (See"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Early positive pressure'.)
●In preterm infants who require intubation soon after birth, we provide early surfactant therapy. (See"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Surfactant therapy'.)
●In preterm infants with respiratory failure, we use a mechanical ventilation strategy that aims to minimize ventilator-induced lung injury (VILI). The approach is summarized in the table (table 3) and is discussed in detail separately. (See"Approach to mechanical ventilation in very preterm neonates", section on 'Clinical approach'.)
●In infants with severe persistent respiratory failure despite optimal settings on conventional ventilation, a trial of high-frequency ventilation (HFV) is used to minimize VILI. This is discussed separately. (See"Approach to mechanical ventilation in very preterm neonates", section on 'Transition to HFV'.)
The role that mechanical ventilation and oxygen toxicity play in the pathogenesis of BPD is discussed separately. (See"Bronchopulmonary dysplasia (BPD): Clinical features and diagnosis", section on 'Postnatal risk factors'.)
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bronchopulmonary-dysplasia-bpd-prevention - OUR APPROACH - Postnatal glucocorticoids
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We do We do not routinely administer postnatal systemic or inhaled glucocorticoids to prevent BPD. Systemic glucocorticoids are reserved for EPT infants who remain ventilator-dependent and/or require oxygen supplementation >50 percent at two to four weeks postnatal age. This is discussed in detail separately. (See "Postnatal use of glucocorticoids for prevention of bronchopulmonary dysplasia (BPD) in preterm infants" .)
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bronchopulmonary-dysplasia-bpd-prevention - INTERVENTIONS - Overview
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●Measures that are routinely used– The following interventions are generally used in combination to improve outcomes (including a reduction in the risk of BPD) in at-risk preterm infants, especially extremely preterm infants (EPT; gestational age [GA] <28 weeks) (algorithm 1):
•Antenatal glucocorticoid therapy (see"Antenatal corticosteroid therapy for reduction of neonatal respiratory morbidity and mortality from preterm delivery").
•Protective ventilatory strategies that minimize barotrauma or volutrauma in infants who require respiratory support for neonatal respiratory distress (RDS) (table 3) (see"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Early positive pressure'and"Approach to mechanical ventilation in very preterm neonates").
•Mother's breast milk (see"Approach to enteral nutrition in the premature infant"and"Infant benefits of breastfeeding").
•Caffeine(see"Management of apnea of prematurity", section on 'Caffeine').
•Modest fluid restriction (see"Fluid and electrolyte therapy in newborns"and"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Fluid management').
●Measures that are used selectively– Preterm infants who remain ventilator-dependent at one week after birth are at high risk for developing BPD. Such neonates may benefit from additional preventive measures, including:
•Selective us of postnatal glucocorticoid therapy in high-risk EPT infants (see"Postnatal use of glucocorticoids for prevention of bronchopulmonary dysplasia (BPD) in preterm infants").
•Some centers usevitamin Asupplementation (if available) in EPT infants who require mechanical ventilation support (see'Vitamin A'below).
•Selective use of a trial of diuretic therapy (see"Bronchopulmonary dysplasia (BPD): Management and outcome", section on 'Diuretics'and"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Fluid management').
●Measures that are not used– These include:
•Routine use of postnatal glucocorticoid therapy in all at-risk preterm infants. This is because of concerns of adverse effects, particularly adverse neurodevelopmental outcome, with early glucocorticoid therapy, as discussed separately. (See"Postnatal use of glucocorticoids for prevention of bronchopulmonary dysplasia (BPD) in preterm infants", section on 'Adverse effects'.)
•Routine use ofinhaled nitric oxide(iNO), since this does not appear to be effective. (See"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Limited role for inhaled nitric oxide'.)
•Late surfactant administration, since this does not appear to be effective. (See"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Timing'.)
•Use of bronchodilators, since limited evidence did not show efficacy. (See'Unproven interventions'below.)
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bronchopulmonary-dysplasia-bpd-prevention - INTERVENTIONS - Glucocorticoids - -Antenatal glucocorticoids
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Antenatal glucocorticoid therapy is an effective intervention for prevention of respiratory distress syndrome (RDS) resulting in less need for mechanical ventilation and oxygen supplementation (risk factors for BPD). Antenatal glucocorticoids are appropriate for pregnant individuals from 23 to 34 weeks of gestation who are at risk for preterm delivery within the next seven days. This is discussed separately. (See Antenatal glucocorticoid therapy is an effective intervention for prevention of respiratory distress syndrome (RDS) resulting in less need for mechanical ventilation and oxygen supplementation (risk factors for BPD). Antenatal glucocorticoids are appropriate for pregnant individuals from 23 to 34 weeks of gestation who are at risk for preterm delivery within the next seven days. This is discussed separately. (See "Antenatal corticosteroid therapy for reduction of neonatal respiratory morbidity and mortality from preterm delivery" .)
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bronchopulmonary-dysplasia-bpd-prevention - INTERVENTIONS - Glucocorticoids - -Postnatal glucocorticoids
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We do We do not routinely administer postnatal systemic or inhaled glucocorticoids to prevent BPD. Systemic glucocorticoids are reserved for EPT infants who remain ventilator-dependent and/or require oxygen supplementation >50 percent at a postnatal age of two to four weeks. This is discussed in detail separately. (See "Postnatal use of glucocorticoids for prevention of bronchopulmonary dysplasia (BPD) in preterm infants" .)
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bronchopulmonary-dysplasia-bpd-prevention - INTERVENTIONS - Surfactant
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Exogenous surfactant therapy given within the first 30 to 60 minutes after birth is effective in the prevention and treatment of RDS and reduces the need for mechanical ventilation and oxygen supplementation (risk factors for BPD). The use of early surfactant to prevent and treat RDS is discussed separately. (See Exogenous surfactant therapy given within the first 30 to 60 minutes after birth is effective in the prevention and treatment of RDS and reduces the need for mechanical ventilation and oxygen supplementation (risk factors for BPD). The use of early surfactant to prevent and treat RDS is discussed separately. (See "Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Surfactant therapy' .)
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bronchopulmonary-dysplasia-bpd-prevention - INTERVENTIONS - Fluid management
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The goal of fluid management is to maintain neutral or slightly negative fluid balance. Our usual practice is to restrict total fluid intake to 130 to 140 mL/kg per day after the first week of life. However, the fluid status of the patient must be monitored frequently to avoid dehydration or overhydration as fluid needs widely vary in preterm infants due to differences in insensible fluid loss. Caloric intake and growth should be closely monitored. (See The goal of fluid management is to maintain neutral or slightly negative fluid balance. Our usual practice is to restrict total fluid intake to 130 to 140 mL/kg per day after the first week of life. However, the fluid status of the patient must be monitored frequently to avoid dehydration or overhydration as fluid needs widely vary in preterm infants due to differences in insensible fluid loss. Caloric intake and growth should be closely monitored. (See "Fluid and electrolyte therapy in newborns" .)
The available evidence does not support the routine use of diuretic therapy in maintaining a neutral or negative fluid balance to prevent BPD. However, it may be reasonable to selectively use diuretic therapy as a trial in chronically ventilator-dependent infants with moderate to severe pulmonary impairment despite adequate fluid restriction. This is discussed in greater detail separately. (See"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Fluid management'.)
Use of diuretics in the management of infants with established BPD is discussed separately. (See"Bronchopulmonary dysplasia (BPD): Management and outcome", section on 'Diuretics'.)
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bronchopulmonary-dysplasia-bpd-prevention - INTERVENTIONS - Ventilation strategies to minimize lung injury
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Mechanical ventilation (MV) has been a lifesaving intervention in the care of preterm infants at risk for RDS due to premature lung development. However, mechanical ventilation causes tissue injury and inflammation due to volutrauma that contributes to BPD. As a result, MV strategies aim to minimize lung injury while achieving adequate oxygenation and ventilation. These strategies include: Mechanical ventilation (MV) has been a lifesaving intervention in the care of preterm infants at risk for RDS due to premature lung development. However, mechanical ventilation causes tissue injury and inflammation due to volutrauma that contributes to BPD. As a result, MV strategies aim to minimize lung injury while achieving adequate oxygenation and ventilation. These strategies include:
●Avoidance of MV through preferential use of noninvasive respiratory support (eg, nasal continuous positive airway pressure [nCPAP]) when possible. (See"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Early positive pressure'.)
●Use of volume-targeted ventilation (VTV) using low tidal volumes (4 to 6 mL/kg). (See"Approach to mechanical ventilation in very preterm neonates", section on 'Clinical approach'.)
●Use of high-frequency oscillatory or jet ventilation (HFOV or HFJV) as a rescue therapy. (See"Approach to mechanical ventilation in very preterm neonates", section on 'Transition to HFV'.)
The approach is summarized in the table (table 3), and discussed in greater detail separately. (See"Approach to mechanical ventilation in very preterm neonates".)
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bronchopulmonary-dysplasia-bpd-prevention - INTERVENTIONS - Caffeine
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For most ELBW infants (BW <1000 g), we suggest prophylactic For most ELBW infants (BW <1000 g), we suggest prophylactic caffeine starting on the first day of life. The available clinical trial data suggest this intervention is safe and effective for reducing BPD and perhaps other long-term complications. This is discussed separately. (See "Management of apnea of prematurity", section on 'Caffeine' .)
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bronchopulmonary-dysplasia-bpd-prevention - INTERVENTIONS - Vitamin A
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EPT infants may have EPT infants may have vitamin A deficiency, which may promote the development of BPD [ 2 ]. However, data are conflicting as to whether vitamin A supplementation reduces the incidence of BPD. If there is a benefit, it appears to be modest.
Since the incidence of BPD varies among neonatal intensive care units (NICUs), the decision to usevitamin Asupplementation may depend upon the local incidence of BPD and the availability and cost of the drug [3]. For example, one of the authors of this topic routinely uses vitamin A supplementation at their center as a preventive measure in EPT infants who require mechanical ventilation (if the drug is available); whereas the other author does not routinely use it at their center. At most centers where vitamin A is used, its use is limited to EPT infants who require mechanical ventilation.
Whenvitamin Ais given, it is administered within 24 hours after birth as an intramuscular (IM) injection of 5000 international units. This dose is then provided three times per week for four weeks.
Enteral water-solublevitamin Aisnotused for this purpose because, although it may increases plasma retinol levels in EPT infants [4,5], it does not appear to reduce the severity of BPD [4-6].
Evidence supporting IMvitamin Asupplementation includes the following:
●In a meta-analysis of five trials (884 neonates), IMvitamin Asupplementation compared with control modestly reduced rates of BPD; however, the finding did not achieve statistical significance (68 versus 74 percent; relative risk [RR] 0.93, 95% CI 0.86-1.01) [7].
●A subsequent multicenter retrospective study from the Pediatrix Medical Group of neonates from 2010 to 2012 reported that the shortage ofvitamin Ain the United States that began in 2010 did not affect the incidence of mortality or BPD in the participating NICUs [8]. During the study period, vitamin A supplementation in patients decreased from a level of 27 percent to 2 percent as the supply of vitamin decreased. A multivariable analysis demonstrated that vitamin A supplementation was not an independent risk factor for death or BPD.
●Vitamin Amay be beneficial in a subset of preterm infants, as suggested by a post-hoc subgroup analysis of data from the largest placebo-controlled trial [9]. In this report, the benefit of vitamin A therapy was greater for infants at a lower risk for BPD than those at a higher risk. However, as noted by the authors, data used for this study was from 1996 to 1997 and other aspects of clinical care have changed, which may have impacted these results.
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bronchopulmonary-dysplasia-bpd-prevention - INTERVENTIONS - Breast milk
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Mother's own milk is the preferred form of nutrition for preterm infants as it offers several advantages over formula, including prevention of BPD. (See Mother's own milk is the preferred form of nutrition for preterm infants as it offers several advantages over formula, including prevention of BPD. (See "Human milk feeding and fortification of human milk for premature infants", section on 'Benefits of mother's milk' .)
A meta-analysis of 17 cohort studies and 5 RCTs (8661 neonates) demonstrated that human milk compared with formula is associated with a lower incidence of BPD, although the certainty of this finding is low [10]. In addition, an observational study found breast milk from the mother reduced the risk of BPD and reported a dose-response relationship with an increased reduction in BPD as the volume of consumed breast milk increased [11]. However, the results of this study are limited by the potential of confounding factors.
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bronchopulmonary-dysplasia-bpd-prevention - INTERVENTIONS - Unproven interventions
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Interventions that are ineffective in preventing BPD include sustained inflation in the delivery room for infants requiring respiratory support, Interventions that are ineffective in preventing BPD include sustained inflation in the delivery room for infants requiring respiratory support, inhaled nitric oxide alone or in combination with surfactant, bronchodilators, and supplementation with docosahexaenoic acid.
●Sustained inflation in the delivery room– Sustained lung inflation during neonatal resuscitation in the delivery room may be harmful and should beavoided, as discussed separately. (See"Neonatal resuscitation in the delivery room", section on 'Sustained inflation'.)
●Inhaled nitric oxide(iNO)– The available data do not support the use of iNO (either alone or in combination with surfactant) as an intervention to prevent BPD. We agree with the guidance of the expert panel convened by the National Institute of Health and a 2014 American Academy of Pediatrics clinical report that recommendagainstthe use of iNO in the routine management of preterm infants below 34 weeks gestation who require respiratory support [12,13].
Data on the use of iNO in the management of preterm neonates with RDS are discussed separately. (See"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Limited role for inhaled nitric oxide'.)
However, iNO is a well-established treatment for term or late preterm infants with persistent pulmonary hypertension, as discussed separately. (See"Persistent pulmonary hypertension of the newborn (PPHN): Management and outcome", section on 'Inhaled nitric oxide (iNO)'.)
●Late surfactant therapy– Late deficiency of postnatal surfactant production or surfactant dysfunction has been proposed as a contributor for the pathogenesis of BPD because it may be associated with episodes of respiratory deterioration in ventilator-dependent preterm infants. However, late administration of surfactant does not appear to reduce the risk of BPD, as discussed separately. (See"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Timing'.)
●Combination of steroid and surfactant– Data on the use of combination surfactant plusbudesonideare limited. This therapy cannot be recommended until there are more definitive data establishing its safety and efficacy. The data supporting this intervention are discussed separately. (See"Postnatal use of glucocorticoids for prevention of bronchopulmonary dysplasia (BPD) in preterm infants", section on 'No role for intratracheal glucocorticoids mixed with surfactant'.)
●Bronchodilators– Data on the use of bronchodilators are limited. In a systematic review, only one randomized trial had usable outcome data. In this trial of 173 preterm infants (gestational age less than 31 weeks), salbutamol did not reduce the risk of BPD at 28 days when compared to no intervention/placebo (RR 1.03, 95% CI 0.78-1.37) [14].
●Long-chain fatty acids– Docosahexaenoic acid (DHA) and other omega-3 long-chain polyunsaturated fatty acids (LCPUFAs) are integral components of the brain and retinal phospholipid membrane. Preterm infants miss some of the fetal accretion of DHA, which normally occurs during the third trimester of pregnancy. Based upon the available evidence, direct or indirect LCPUFA supplementation does not appear to prevent BPD. However, LCPUFA supplementation appears to have other beneficial effects in preterm infants, particularly on neurocognitive and visual development. Recommendations regarding maternal and infant LCPUFA supplementation are provided separately. (See"Enteral long-chain polyunsaturated fatty acids (LCPUFA) for preterm and term infants".)
●Superoxide dismutase– Superoxide dismutase is a naturally occurring enzyme that provides defense against oxidative injury, which has been implicated in the pathogenesis of BPD. In the available clinical trials, postnatal administration of superoxide dismutase did not have any apparent benefit in terms of reducing the incidence of BPD, other morbidities, or mortality [15]. Superoxide dismutase is not available for clinical use, and it remains an investigational drug.
●Pentoxifylline–Pentoxifyllineis a xanthine derivative with anti-inflammatory properties. The use of nebulized pentoxifylline as a preventive measure for BPD was studied in a single small pilot randomized trial [16,17]. As such, additional data are needed before pentoxifylline can be recommended as a routine measure to prevent or treat BPD in neonates. Studies investigating the use of pentoxifylline in the treatment of neonatal sepsis are discussed elsewhere. (See"Neonatal bacterial sepsis: Treatment, prevention, and outcome in neonates <35 weeks gestation", section on 'Therapies with uncertain benefit'and"Neonatal bacterial sepsis: Treatment, prevention, and outcome in neonates ≥35 weeks gestation".)
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bronchopulmonary-dysplasia-bpd-prevention - SOCIETY GUIDELINE LINKS
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Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See"Society guideline links: Bronchopulmonary dysplasia".)
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bronchopulmonary-dysplasia-bpd-prevention - INFORMATION FOR PATIENTS
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UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5thto 6thgrade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10thto 12thgrade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see"Patient education: Bronchopulmonary dysplasia (The Basics)")
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bronchopulmonary-dysplasia-bpd-prevention - SUMMARY AND RECOMMENDATIONS
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●Definition– Clinically, BPD is defined as an ongoing need for supplemental oxygen and/or respiratory support at either 28 days postnatal age or 36 weeks postmenstrual age (calculator 1) in a preterm neonate with radiographic evidence of parenchymal lung disease (image 1). Various criteria are used to define BPD (table 2). (See'Terminology'above.)
●Effective interventions– Interventions that are effective for reducing the risk of bronchopulmonary dysplasia (BPD) in extremely preterm (EPT) infants (gestational age [GA] <28 weeks) who are at risk for BPD include (algorithm 1) (see'Our approach'above and'Interventions'above):
•Antenatal glucocorticoid therapy– Antenatal glucocorticoid therapy for pregnant individuals <34 weeks gestation who are at high risk for preterm delivery, which is discussed in detail separately. (See"Antenatal corticosteroid therapy for reduction of neonatal respiratory morbidity and mortality from preterm delivery".)
•Nutrition and fluid management– In all preterm infants, nutritional goals are set to provide adequate caloric intake to promote somatic and lung growth, and fluid intake is adjusted to maintain neutral or slightly negative water balance. Mother's breast milk is the preferred nutritional source, and if not available, donor breast milk is used. These issues are discussed separately. (See"Approach to enteral nutrition in the premature infant"and"Parenteral nutrition in premature infants"and"Fluid and electrolyte therapy in newborns"and"Human milk feeding and fortification of human milk for premature infants"and"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Fluid management'.)
•Oxygen targets– In preterm infants who require supplemental oxygen, target oxygen saturation (SpO2) levels are set for values between 90 and 95 percent, as discussed separately. (See"Neonatal target oxygen levels for preterm infants", section on 'Oxygen target levels'.)
•Ventilation strategies that minimize lung injury– Use of ventilation strategies that minimize lung injury, including preferential use of noninvasive modalities. The approach to mechanical ventilation in preterm infants is summarized in the table (table 3) and discussed in detail separately. (See"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Clinical approach'and"Approach to mechanical ventilation in very preterm neonates".)
•Caffeinetherapy– Earlycaffeinetherapy is routinely given to all EPT infants, as discussed separately. (See"Management of apnea of prematurity", section on 'Caffeine'.)
•Vitamin Asupplementation– The use ofvitamin Asupplementation is center-dependent. If vitamin A is available, practitioners may consider its administration to EPT infants who require ventilatory support; however, the relative benefit of vitamin A supplementation in this setting appears to be small. (See'Vitamin A'above.)
•Postnatal glucocorticoids– We donotroutinely administer postnatal systemic or inhaled glucocorticoids to prevent BPD. Systemic glucocorticoids are reserved for EPT infants who remain ventilator-dependent and/or require oxygen supplementation >50 percent at a postnatal age of two to four weeks. This is discussed in detail separately. (See"Postnatal use of glucocorticoids for prevention of bronchopulmonary dysplasia (BPD) in preterm infants".)
●Ineffective interventions– Interventions that do not appear to be effective for prevention of BPD in EPT infants include (see'Unproven interventions'above):
•Sustained lung inflation during neonatal resuscitation (see"Neonatal resuscitation in the delivery room", section on 'Sustained inflation')
•Inhaled nitric oxide (iNO) (see"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Limited role for inhaled nitric oxide')
•Late surfactant therapy (see"Respiratory distress syndrome (RDS) in preterm neonates: Management", section on 'Timing')
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bronchopulmonary-dysplasia-bpd-prevention - ACKNOWLEDGMENT
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The editorial staff at UpToDate acknowledge James Adams, Jr., MD, who contributed to an earlier version of this topic review.
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bronchopulmonary-sequestration - SUMMARY AND RECOMMENDATIONS
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●Definition and types– Bronchopulmonary sequestration (BPS) is a rare congenital abnormality of the lower respiratory tract. It consists of a nonfunctioning mass of lung tissue that lacks normal communication with the tracheobronchial tree and receives its arterial blood supply from the systemic circulation. The connections to the tracheobronchial tree and systemic artery distinguishes BPS from congenital pulmonary airway malformation (CPAM). (See'Anatomic characteristics'above.)
•An intralobar sequestration (ILS) is located within a normal lobe and lacks its own visceral pleura. This type often has aberrant connections to bronchi, lung parenchyma, or the gastrointestinal tract and often presents with recurrent infections.
•An extralobar sequestration (ELS) is located outside the normal lung and has its own visceral pleura. Infectious complications are rare, except in ELS with connections to the gastrointestinal tract or intrapulmonary structures, which is unusual.
●Associated anomalies– Congenital abnormalities that are sometimes associated with BPS include congenital diaphragmatic hernia, vertebral anomalies, congenital heart disease, pulmonary hypoplasia, colonic duplication, and CPAM. These associated anomalies are more common in ELS compared with ILS. (See'Associated anomalies'above.)
●Clinical presentation– The clinical presentation of BPS is variable and depends on the type, size, and location of the lesion. Many cases are initially detected by prenatal ultrasound; most of these regress during gestation, while others progress and hydrops may develop. The affected newborn is usually asymptomatic but sometimes presents with respiratory distress. Some cases (usually ILS) present with recurrent pneumonia during infancy or childhood. (See'Clinical presentation'above.)
●Postnatal evaluation– All cases of BPS or other congenital abnormalities of the lower airway should be further evaluated with postnatal imaging. This includes cases that regressed or appeared to resolve in utero because few lesions resolve completely and advanced imaging is more sensitive than prenatal ultrasound for detecting small lesions. (See'Postnatal imaging'above.)
•After birth, the first step is a plain chest radiograph. On a chest radiograph, sequestrations typically appear as a uniformly dense mass within the thoracic cavity or pulmonary parenchyma (image 4). Recurrent infection can lead to cystic areas within the mass, and there may be air-fluid levels if the lesion communicates with a bronchus.
•The second step is advanced thoracic imaging, the timing of which depends on the patient's characteristics, as outlined in the algorithm (algorithm 1). This is to confirm the diagnosis, including identifying the aberrant artery that distinguishes BPS, and to help with surgical planning.
●Management
•Symptomatic– Infants with BPS that is causing any respiratory symptoms (respiratory distress or tachypnea) are treated with surgical excision; surgery is curative and is associated with minimal morbidity. The procedure is performed urgently in newborns with significant respiratory distress. Surgical resection is typically performed electively in older children who present with infection. (See'Symptomatic patients'above.)
•Asymptomatic,high risk– For asymptomatic patients of any age with characteristics that suggest a high risk for developing complications (large lesions occupying >20 percent of the hemithorax, bilateral or multifocal cysts, pneumothorax, or a family history of pleuropulmonary blastoma-associated conditions (table 1)), we suggest surgical resection rather than observation (Grade 2C). (See'High risk'above.)
•Asymptomatic, low risk– For asymptomatic patients without these high-risk characteristics, either elective surgical resection or conservative management with observation are reasonable options and practice varies (algorithm 1). (See'Low risk'above.)
-In our practice, we generally perform surgery for all asymptomatic infants with BPS, regardless of the lesion's size and characteristics. The surgery is elective and is usually performed between 6 and 12 months of age. Our preference for surgery is based on the good outcomes after surgery and on the risk of developing complications (primarily infection) if surgery is not performed. The likelihood and risk factors for developing complications if surgery is not performed are poorly delineated. (See'Outcome'above.)
-Other authors prefer to observe asymptomatic patients, especially if the lesion is small, noncystic, and appears to be consistent with ELS. Optimal surveillance strategies for observation have not been determined.
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bronchopulmonary-sequestration - INTRODUCTION
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Bronchopulmonary sequestration (BPS), sometimes referred to simply as pulmonary sequestration, is a rare congenital abnormality of the lower airway. It consists of a nonfunctioning mass of lung tissue that lacks normal communication with the tracheobronchial tree and that receives its arterial blood supply from the systemic circulation [1].
BPS can present in several ways. Extralobar BPS is often identified on prenatal ultrasound and becomes symptomatic early in life, whereas intralobar BPS is more commonly identified later in life secondary to recurrent infection.
The postnatal presentation and management of BPS will be discussed below. Prenatal manifestations and management are described in a separate topic review. (See"Bronchopulmonary sequestration: Prenatal diagnosis and management".)
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bronchopulmonary-sequestration - DEFINITIONS
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BPS is a nonfunctioning mass of lung tissue, with airway and alveolar elements, that lacks normal communication with the tracheobronchial tree and receives its arterial blood supply from the systemic circulation. The subtypes are classified anatomically, as follows:
●Intralobar sequestration (ILS)– An ILS (also known as intrapulmonary sequestration) is located within a normal lobe and lacks its own visceral pleura. ILS accounts for approximately 75 percent of BPS.
●Extralobar sequestration (ELS)– An ELS (also known as extrapulmonary sequestration) is located outside the normal lung and has its own visceral pleura. Occasionally, it is located below the diaphragm [2]. ELS accounts for approximately 25 percent of BPS and is more likely to be associated with other congenital anomalies.
●Hybrid BPS/congenital pulmonary airway malformation (CPAM) lesions– In a hybrid lesion, BPS (either ILS or ELS) occurs in combination with a CPAM. These hybrid lesions have histologic features of CPAM, have a blood supply from a systemic artery, and have been reported in a substantial proportion of cases of BPS [3,4]. (See"Congenital pulmonary airway malformation".)
●Bronchopulmonary foregut malformation– This term is usually used to refer to a rare variant of sequestration in which the sequestered lung tissue is connected to the gastrointestinal tract [5]. This may occur in either ILS or ELS. Occasionally, bronchopulmonary foregut malformation is used as a general term to include all foregut malformations.
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bronchopulmonary-sequestration - EPIDEMIOLOGY
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Congenital abnormalities of the lower respiratory tract are rare, found in approximately 1 in 10,000 to 35,000 live births [4]. Among these, the most common is congenital pulmonary airway malformation (CPAM), while BPS represents only 0.15 to 6.40 percent [6]. In several reports, even tertiary care referral centers diagnose less than one case per year of BPS [7-10].
Intralobar sequestration (ILS) is overall the most common form, comprising approximately 75 to 90 percent of sequestrations, while 10 to 25 percent are extralobar sequestration (ELS) [6,11]. The difference in prevalence of the disorders may be related to the pathogenic mechanisms, as discussed below. Males and females are equally affected with ILS, while ELS has a male predominance in most [1,10], but not all [3], reports. In a series of ELS cases diagnosed antenatally, the ratio of males to females was three to one [12,13]. In contrast, bronchopulmonary foregut malformation has a female predominance [5].
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bronchopulmonary-sequestration - PATHOGENESIS
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The embryologic basis for the development of BPS and other congenital abnormalities of the lower airway are not fully understood [5,14]. The most widely accepted embryologic theory is that BPS originates early in the pseudoglandular stage of lung development (5 to 17 weeks of gestation), prior to separation of the aortic and pulmonary circulations [15]. This would explain the wide spectrum of pathology observed, including the connections to the systemic circulation, the presence of separate visceral pleura in extralobar sequestration (ELS) or lack thereof in intralobar sequestration (ILS), the occurrence of hybrid lesions with features of BPS and congenital pulmonary airway malformation (CPAM), and the occasional associations with bronchogenic cysts or connections to the foregut, as well as associated anomalies such as congenital diaphragmatic hernia [15-17]. In utero airway obstruction may contribute to some of the morphologic changes [18].
Another proposed explanation is that a portion of the developing lung is mechanically separated from the rest of the organ by compression from vascular structures, traction by aberrant systemic vessels, or inadequate pulmonary blood flow. However, this mechanical hypothesis does not completely explain all types of lesions, specifically bronchopulmonary foregut malformation [5,14].
In the past, ILS was proposed to be an acquired rather than a developmental lesion. This hypothesis was suggested by the late presentations of ILS in historical series and also by observations that systemic arterial collaterals (resembling BPS) occasionally develop in the setting of pulmonary inflammatory processes [19,20].
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bronchopulmonary-sequestration - ANATOMIC CHARACTERISTICS
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Sequestrations are characterized by their location, connection to pulmonary or other structures, vascular supply, and association with other abnormalities. By definition, their arterial blood supply is from the systemic circulation.
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bronchopulmonary-sequestration - ANATOMIC CHARACTERISTICS - Intralobar sequestration
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Intralobar sequestrations (ILS) are located within a normal lobe and lack their own visceral pleura. Most ILS occur in the lower lobes, but they can occur anywhere within the thorax [ Intralobar sequestrations (ILS) are located within a normal lobe and lack their own visceral pleura. Most ILS occur in the lower lobes, but they can occur anywhere within the thorax [ 21 ]. Approximately 60 percent are located in the posterior basal segment of the left lower lobe [ 1,5,8,11,22 ], and rare instances of bilateral ILS (or ILS with contralateral extralobar sequestration [ELS]) have been reported [ 23 ]. They generally have no bronchial connection to the proximal airway. If a connection exists, it is abnormal. However, anomalous connections can link the sequestration to other bronchi, or lung parenchyma, and there are connections to the gastrointestinal tract in approximately 10 percent, constituting a bronchopulmonary foregut malformation [ 11,15 ]. These connections and/or the pores of Kohn may allow bacteria to enter the sequestration and cause recurrent infection, a common finding in ILS ( picture 1 ).
The arterial supply usually is derived from the lower thoracic or upper abdominal aorta. In a series of 25 cases, 16 had a single arterial trunk and the remainder had multiple arterial vessels (image 1A-B) [24]. Venous drainage is usually normal to the left atrium, although abnormal connections to the vena cava, azygous vein, or right atrium may occur [11].
On pathologic examination, there are often changes at the pleural surface overlying the abnormal region [25]. On cut section, the parenchyma of the sequestration is usually sharply demarcated from the adjacent normal tissue. The abnormal parenchyma has enlarged airspaces and thickening of the airspace wall (picture 1). The airways of the lesion are dilated and filled with mucus, with regions of inflammation, mucus accumulation, and microcystic changes, with more distortion of the lung parenchyma than is typically seen in ELS. Sometimes, dilated lymphatic channels are associated with the lesion (picture 2). (See"Congenital anomalies of the intrathoracic airways and tracheoesophageal fistula".)
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bronchopulmonary-sequestration - ANATOMIC CHARACTERISTICS - Extralobar sequestration
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Extralobar sequestrations (ELS) are located outside the normal lung and have their own visceral pleura, with a pedicle that contains the vascular connections. They vary in size but usually are relatively small compared with the normal lobes. The vast majority are in the left hemithorax, and the most common location is between the left lower lobe and hemidiaphragm (80 percent) [ Extralobar sequestrations (ELS) are located outside the normal lung and have their own visceral pleura, with a pedicle that contains the vascular connections. They vary in size but usually are relatively small compared with the normal lobes. The vast majority are in the left hemithorax, and the most common location is between the left lower lobe and hemidiaphragm (80 percent) [ 26,27 ]. Occasionally, ELS may present within or below the diaphragm or in the retroperitoneum, particularly in the region of the adrenal gland where they may mimic a suprarenal neuroblastoma [ 28 ]. Like ILS, ELS lesions lack a bronchial connection to the normal proximal airway. They may connect to the gastrointestinal tract or, rarely, to intrapulmonary structures [ 11 ]. Because intrapulmonary connections are uncommon in ELS, infectious complications are also uncommon. The arterial supply of ELS usually comes from an aberrant vessel arising from the thoracic aorta [ 11 ]. The vessel is usually small, with low flow. Lesions typically have anomalous venous drainage to the right atrium, vena cava, or azygous systems [ 29 ]. On histologic examination, ELS may resemble normal lung or show parenchymal maldevelopment similar to the small-cyst type of congenital pulmonary airway malformation (CPAM) [ 25 ].
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bronchopulmonary-sequestration - ANATOMIC CHARACTERISTICS - Hybrid BPS/CPAM lesions
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Hybrid lesions, with features of BPS and CPAM, occur in a substantial proportion of BPS [ Hybrid lesions, with features of BPS and CPAM, occur in a substantial proportion of BPS [ 3,30,31 ] and comprise 15 to 40 percent of all cystic lung lesions [ 32 ]. These lesions have blood supply from a systemic artery consistent with BPS, but they also have histologic features of CPAM. In one report, five cases of ILS and one of ELS that were diagnosed prenatally had a systemic artery detected at surgical resection, but histology was consistent with CPAM [ 30 ]. In another series, 23 of 46 cases of ELS had histologic features of CPAM type 2 [ 3 ]. Of these, 11 had rhabdomyomatous degeneration.
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bronchopulmonary-sequestration - CLINICAL PRESENTATION
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The clinical presentation of BPS is variable and depends upon the type, size, and location of the lesion. Many cases are initially detected by routine prenatal ultrasound examination. Most affected newborns are asymptomatic. If symptomatic, BPS usually presents with respiratory distress in the neonatal period. Intralobar sequestration (ILS) or hybrid forms often present later in life, with infection [1,3,5,7,8,14,22,33]. Presentation with infection is less likely with extralobar sequestration (ELS). ELS may also be diagnosed incidentally on a chest radiograph taken for other reasons.
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bronchopulmonary-sequestration - CLINICAL PRESENTATION - Prenatal
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On prenatal ultrasound, BPS appears as a homogenous echogenic thoracic mass, usually solid-appearing, triangular, and often located in the lower hemithorax adjacent to the diaphragm. The size of the lesion varies considerably, ranging from very small to one that occupies most of the hemithorax, causing mediastinal shift [ On prenatal ultrasound, BPS appears as a homogenous echogenic thoracic mass, usually solid-appearing, triangular, and often located in the lower hemithorax adjacent to the diaphragm. The size of the lesion varies considerably, ranging from very small to one that occupies most of the hemithorax, causing mediastinal shift [ 34-38 ]. BPS may be difficult or impossible to distinguish from microcystic congenital pulmonary airway malformations (CPAM), unless a systemic arterial feeder can be identified ( image 2 ). (See "Bronchopulmonary sequestration: Prenatal diagnosis and management", section on 'Prenatal diagnosis' .)
In the majority of cases, the lesion regresses during the course of gestation. Occasionally, hydrops develops, likely because of vascular compression [34,39,40]. There are no reliable criteria for determining which lesions will grow and develop hydrops versus those that will stabilize or regress [37]. Management of prenatally detected BPS including hydrops and planning the method and optimal setting for delivery are discussed separately [41]. (See"Bronchopulmonary sequestration: Prenatal diagnosis and management".)
In cases demonstrating in utero regression, postpartum imaging is still required because few lesions resolve completely. (See'Postnatal imaging'below.)
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bronchopulmonary-sequestration - CLINICAL PRESENTATION - Neonatal period
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Infants with BPS or other congenital abnormalities of the lower airway may be either asymptomatic or symptomatic at birth: Infants with BPS or other congenital abnormalities of the lower airway may be either asymptomatic or symptomatic at birth:
●Asymptomatic – Most infants with BPS are asymptomatic at birth. The lesion may have been identified on prenatal ultrasound or identified incidentally during a postnatal evaluation for other congenital anomalies.
●Symptomatic – Some infants with prenatally diagnosed lung lesions present with respiratory distress at birth or shortly thereafter; this may occur with either ILS or ELS and is more likely if the lesion is large. The symptoms are usually due to large lesions that limit the volume of the normal lung; rarely, they are caused by high-output heart failure if the sequestration takes a large portion of the systemic arterial flow, thus creating a significant left-to-right shunt.
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bronchopulmonary-sequestration - CLINICAL PRESENTATION - Postneonatal
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Among infants who are asymptomatic at birth, some will become symptomatic later in infancy, childhood, or even adulthood, but the natural history and magnitude of risk is poorly delineated. (See Among infants who are asymptomatic at birth, some will become symptomatic later in infancy, childhood, or even adulthood, but the natural history and magnitude of risk is poorly delineated. (See 'Low risk' below.)
Other individuals remain asymptomatic throughout life but come to attention when the lesion is detected as an incidental finding on a chest radiograph. Unfortunately, the percentage of those who will become symptomatic is not known, because the natural history of infants who are asymptomatic at birth is not well described. As a result, the optimal management of an asymptomatic infant is also uncertain, as discussed below. (See'Asymptomatic patients'below and"Congenital pulmonary airway malformation", section on 'Asymptomatic'.)
The most common symptomatic presentation after the neonatal period is with pulmonary infection, typically presenting with fever and cough and sometimes hemoptysis or chest pain (image 3) [33,42]. This is most likely for those with ILS, which comprise approximately 75 percent of BPS. Rare complications of either ELS or ILS include heart failure due to excessive flow through the aberrant artery [11,43], massive bleeding [44,45], or torsion [46]. Cases have been reported of fibrous mesothelioma [47] and carcinoma [25,48,49] arising within ILS. These disorders may be related to an association of ILS with CPAM. (See"Congenital pulmonary airway malformation".)
Patients with ELS are unlikely to develop infection. Those that do present with infection tend to be hybrid lesions with CPAM [3]. It is clear that some patients with ELS will remain asymptomatic throughout life, but the likelihood of this outcome is unknown.
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bronchopulmonary-sequestration - CLINICAL PRESENTATION - Associated anomalies
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Congenital anomalies may be associated with BPS, occurring more frequently in patients with ELS than ILS. In a series of 28 cases in children and adults, associated malformations occurred in 43 percent of ELS and 17 percent of ILS [ Congenital anomalies may be associated with BPS, occurring more frequently in patients with ELS than ILS. In a series of 28 cases in children and adults, associated malformations occurred in 43 percent of ELS and 17 percent of ILS [ 6 ]. Similar proportions were seen in an older series of 540 cases [ 50 ]. Associated anomalies include congenital diaphragmatic hernia, vertebral anomalies, congenital heart disease, and colonic duplication [ 5,14 ]. Infants with a large BPS may have pulmonary hypoplasia due to mass effects in utero.
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bronchopulmonary-sequestration - EVALUATION - Postnatal imaging
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All cases of BPS or other congenital abnormalities of the lower airway should be further evaluated with imaging. This includes cases that regressed or appeared to resolve in utero because few lesions resolve completely and advanced imaging is more sensitive than prenatal ultrasound for detecting small lesions. All cases of BPS or other congenital abnormalities of the lower airway should be further evaluated with imaging. This includes cases that regressed or appeared to resolve in utero because few lesions resolve completely and advanced imaging is more sensitive than prenatal ultrasound for detecting small lesions.
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bronchopulmonary-sequestration - EVALUATION - Postnatal imaging - -Suggested protocol
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After birth, the first step is a plain chest radiograph. The second step is advanced imaging, the timing of which depends on the patient's characteristics, as outlined in the algorithm ( After birth, the first step is a plain chest radiograph. The second step is advanced imaging, the timing of which depends on the patient's characteristics, as outlined in the algorithm ( algorithm 1 ) and discussed below:
●High risk– We suggest immediate advanced thoracic imaging with computed tomography (CT) or magnetic resonance imaging (MRI) for infants with any of the following characteristics:
•Any symptoms (eg, respiratory distress)
•Large BPS (occupying >20 percent of the hemithorax on ultrasonography or plain radiographs)
•Risk factors for pleuropulmonary blastoma (bilateral or multifocal cysts, pneumothorax, or a family history of pleuropulmonary blastoma-associated conditions (table 1))
The purpose of the advanced imaging is to confirm the diagnosis, identify the aberrant artery, and help with surgical planning [51]. Doppler ultrasonography also may be helpful to define the aberrant artery. These techniques have replaced the need for angiography to identify the vascular supply (image 1B).
●Low risk– Infants who are asymptomatic and do not have the high-risk characteristics outlined above should have advanced thoracic imaging (CT or MRI) by six months of age to confirm the diagnosis and examine further for characteristics that require surgical intervention. This includes infants with normal results of the postnatal chest radiograph, which may not be sufficiently sensitive to detect a small BPS.
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bronchopulmonary-sequestration - EVALUATION - Postnatal imaging - -Radiographic appearance
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●Chest radiograph– On a chest radiograph, sequestrations typically appear as a uniformly dense mass within the thoracic cavity or pulmonary parenchyma (image 4) [52]. Recurrent infection can lead to the development of cystic areas within the mass [52,53]. Air-fluid levels due to bronchial communication are seen in 26 percent of intralobar sequestrations (ILS) [54].
Most sequestrations occur in the lower lobes. However, they can occur anywhere within the thorax, and extralobar sequestration (ELS) sometimes occurs in a subdiaphragmatic location or as a retroperitoneal mass. The left hemithorax is almost always involved in ELS, and it is usually involved in ILS. (See'Anatomic characteristics'above.)
●CT– The parenchymal abnormalities associated with BPS are best visualized using CT, although their appearance is variable [54,55]. The most common appearance is a solid mass that may be homogeneous or heterogeneous, sometimes with cystic changes (image 5). Less frequent findings include a large cavitary lesion with an air-fluid level, a collection of many small cystic lesions containing air or fluid, or a well-defined cystic mass. Emphysematous changes at the margin of the lesion are characteristic, although they may not be visible on the chest radiograph.
Conventional CT does not consistently demonstrate the aberrant systemic artery, with visualization in 16 of 24 cases in one series [55]. Lack of visualization was thought to be due to the small size (sometimes as small as 1 mm) or unfavorable orientation of the vessel. These small vessels may be detected by contrast-enhanced or helical CT, which also enables evaluation of abnormalities in the lung parenchyma or airways (image 6) [54,56,57]. Advances in the use of multidetector CT angiography have improved our ability to simultaneously visualize the arterial supply, venous drainage, and parenchymal involvement of pulmonary sequestrations and may make this the diagnostic procedure of choice (image 1A) [58].
●MRI– MRI can demonstrate the location of the lesion and define the aberrant artery and venous drainage, especially if enhanced three-dimensional magnetic resonance angiography (MRA) is used [54,59,60]. However, CT allows sharper delineation of thin-walled cysts and emphysematous changes than MRI [54]. Advanced imaging with either CT and MRI are adequate to evaluate most infants, and the choice between these techniques depends primarily on institutional or clinician preference.
●Ultrasonography– Ultrasonography is not generally necessary in the evaluation of BPS. CT and MRI are superior for identifying the vascular supply, but if these studies are not available, Doppler ultrasound may be helpful to identify the characteristic aberrant systemic artery that arises from the aorta and to delineate venous drainage. In addition, ultrasonography can be used to guide biopsy of a subdiaphragmatic mass [54,55,61,62]. The typical sonographic appearance of BPS is an echogenic homogeneous mass that may be well defined or irregular [54]. However, some lesions have a cystic or more complex appearance.
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bronchopulmonary-sequestration - DIAGNOSIS
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Extralobar sequestration (ELS) may be first suspected based on prenatal ultrasonography. Intralobar sequestration (ILS) is more often suspected in an older infant or child who presents with recurrent pulmonary infection. Both types of BPS may be identified as an incidental finding on a plain radiograph in an asymptomatic child. Subsequently, a provisional diagnosis can be made in some cases by advanced imaging (computed tomography [CT] or magnetic resonance imaging [MRI]), if an aberrant systemic artery can be identified with confidence. Advanced imaging may help to distinguish among ILS, ELS, and hybrid lesions but is not completely reliable in making these distinctions. The final definitive diagnosis is only made by pathologic examination after surgical resection. (See'Anatomic characteristics'above.)
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bronchopulmonary-sequestration - DIFFERENTIAL DIAGNOSIS
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The differential diagnosis of BPS includes other cystic lung lesions, such as congenital pulmonary airway malformations (CPAM). In contrast with BPS, CPAMs are connected to the tracheobronchial tree and are supplied from the pulmonary circulation. Hybrid lesions, with features of CPAM and BPS, occur in a substantial proportion of BPS. Advanced imaging (contrast-enhanced computed tomography [CT] or magnetic resonance imaging [MRI]) usually is sufficient to distinguish BPS from these other lesions. (See'Hybrid BPS/CPAM lesions'above and"Congenital pulmonary airway malformation".)
In addition to CPAM, lesions that may coexist with BPS or mimic BPS on prenatal ultrasound or postnatal plain radiographs include other space-occupying chest lesions, including:
●Congenital diaphragmatic hernia (see"Congenital diaphragmatic hernia: Prenatal issues"and"Congenital diaphragmatic hernia (CDH) in the neonate: Clinical features and diagnosis")
●Bronchogenic cyst (see"Congenital anomalies of the intrathoracic airways and tracheoesophageal fistula", section on 'Bronchogenic cyst')
●Mediastinal tumors such as a teratoma or neuroblastoma (see"Epidemiology, pathogenesis, and pathology of neuroblastoma")
The radiographic appearances of other congenital abnormalities of the lung are discussed in detail separately. (See"Radiographic appearance of developmental anomalies of the lung".)
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bronchopulmonary-sequestration - MANAGEMENT
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The approach to treatment depends upon whether the patient has symptoms (respiratory distress or recurrent infections) or is asymptomatic.
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bronchopulmonary-sequestration - MANAGEMENT - Symptomatic patients
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All patients with BPS who are symptomatic should undergo surgical excision, which is curative and is associated with minimal morbidity [ All patients with BPS who are symptomatic should undergo surgical excision, which is curative and is associated with minimal morbidity [ 31,41,63,64 ]. Surgery is performed urgently in newborns with significant respiratory distress. It may be done electively in older children who present with recurrent infection, which is usually due to intralobar sequestration (ILS) ( algorithm 1 ). Advanced thoracic imaging (computed tomography [CT] or magnetic resonance imaging [MRI]) should be performed prior to surgery to confirm the diagnosis and assist in surgical planning. (See 'Postnatal imaging' above.)
Complete excision of ILS usually requires lobectomy or segmental resection. Resection of extralobar sequestration (ELS) is simpler because the lesion has its own pleural investment. With both types, all vascular connections to the lesion must be identified and ligated. The arterial supply of these lesions may arise from the subdiaphragmatic aorta, and careful identification of the feeding vessel is crucial. Thoracoscopic lobectomy is an alternative to thoracotomy in infants and older children with ILS or ELS [65-67]. For lesions with a single, well-characterized systemic arterial supply and where high-output cardiac failure is a concern, treatment by arterial embolization may be an effective option for initial therapy. Case series describe treatment using a variety of embolization techniques [68-73]. Lesions with multiple feeding arteries may require repeated procedures, making embolization less appealing.
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46
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bronchopulmonary-sequestration - MANAGEMENT - Asymptomatic patients
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Infants with suspected BPS who are asymptomatic at birth should be closely observed for the first few days of life as some may develop symptoms in the immediate postnatal period [ Infants with suspected BPS who are asymptomatic at birth should be closely observed for the first few days of life as some may develop symptoms in the immediate postnatal period [ 74 ]. For infants and children who remain completely asymptomatic, the decision between surgical management and observation is controversial [ 75,76 ]. Management decisions for these patients are similar to those for asymptomatic patients with other congenital abnormalities of the lower airways, the most common of which are congenital pulmonary airway malformations (CPAM).
Our approach toasymptomaticpatients with BPS depends on the results of the imaging work-up, as outlined in the algorithm (algorithm 1). This algorithm applies to all congenital abnormalities of the lower airway identified on prenatal ultrasound, among which BPS will be a minority.
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47
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bronchopulmonary-sequestration - MANAGEMENT - Asymptomatic patients - -High risk
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We suggest early surgical resection for patients with any of the following characteristics, which suggest increased risk for developing complications: We suggest early surgical resection for patients with any of the following characteristics, which suggest increased risk for developing complications:
●Large lesion (occupies ≥20 percent of the hemithorax)
●Characteristics suggesting risk for pleuropulmonary blastoma (bilateral or multifocal cysts, pneumothorax, or a family history of pleuropulmonary blastoma-associated conditions (table 1))
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48
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bronchopulmonary-sequestration - MANAGEMENT - Asymptomatic patients - -Low risk
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For asymptomatic patients with none of the above characteristics on advanced imaging, either elective surgical resection or observation is a reasonable option ( For asymptomatic patients with none of the above characteristics on advanced imaging, either elective surgical resection or observation is a reasonable option ( algorithm 1 ). The decision is influenced by the family's preferences after a detailed discussion of the potential benefits and risks of each approach.
●Elective surgical resection– In our practice, we generally perform surgery for asymptomatic infants with BPS, even those considered at low risk for developing complications of BPS. We generally perform this elective surgery between 6 and 12 months of age. Surgery may not be appropriate for some infants who have increased surgical risks due to coexisting congenital anomalies.
Our rationale for surgery is threefold: First, surgery is curative and not generally associated with significant complications [75,77]. Second, individuals with BPS appear to have a moderate risk for developing infection sometime later in life, particularly if the lesion is an ILS [4,17,74]. When infection or respiratory symptoms do develop, surgery becomes urgent and is associated with an increased risk of postoperative complications (eg, air leak, effusion, or pneumonia) compared with elective surgery performed in asymptomatic patients (17 versus 5 percent in one of these reports [78]). Third, imaging is not always able to distinguish between BPS and CPAM or hybrid lesions, and CPAM or hybrid lesions are associated with a risk of developing complications (infection or malignant degeneration) if they are left in place. A secondary consideration is that early surgery may have advantages for compensatory lung growth, although pulmonary function outcomes are generally good for either early or later surgery. (See"Congenital pulmonary airway malformation", section on 'Asymptomatic patients'.)
●Observation– Some authors recommend observation rather than surgery for asymptomatic patients, particularly if the lesion is small, noncystic, and appears to be consistent with ELS [76,79]. If observation is chosen, both chest radiographs and advanced thoracic imaging (CT or MRI) have been recommended for monitoring of these patients, though there is no consensus on the optimal strategy for imaging [80,81].
Thus, the optimal management for asymptomatic low-risk infants remains unclear because of limited information about the natural history of BPS and difficulty establishing a definitive diagnosis by imaging. Indeed, most case series include infants with either BPS or CPAM and report outcomes without distinguishing between the conditions. For asymptomatic infants managed conservatively (without surgery), the incidence of complications varies widely in different reports, ranging from 3 to 86 percent [76,78,82,83]. The complications are primarily infection or respiratory symptoms, typically occur between 7 and 24 months of age, and require surgery. These analyses do not report specifically on the risks for complications associated with BPS versus CPAM, or for ELS versus ILS, but small case series suggest that complications are particularly common in individuals with ILS [33].
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bronchopulmonary-sequestration - OUTCOME
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In the absence of other significant congenital anomalies, the prognosis for children with BPS is generally very good [6,77,80,81,84,85]. Most case series do not distinguish outcomes for BPS from those for other congenital abnormalities of the lower airway, particularly congenital pulmonary airway malformations (CPAM).
For asymptomatic infants with CPAM or BPS who were managed conservatively (without surgery), the outcome is not well established, since the incidence of complications (such as infection) varies widely in different reports, as discussed above (see'Low risk'above). Furthermore, most of the available data come from series in which most infants had CPAM rather than BPS.
For symptomatic infants who undergo emergency surgery, at least 20 percent have postoperative complications, which include air leak, infection, or effusion [78]. For asymptomatic infants who undergo elective surgery, approximately 10 percent have postoperative complications.
Long-term pulmonary outcomes for both of these groups are generally good and appear to depend upon the extent of the lung resection. The remaining lung parenchyma undergoes compensatory growth and development [85]. These outcomes vary across different reports, probably reflecting differences in patient selection (eg, asymptomatic lesions identified on prenatal ultrasound and managed conservatively or with elective surgery versus symptomatic lesions requiring surgery during infancy). (See"Congenital pulmonary airway malformation", section on 'Outcome'.)
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bronchopulmonary-sequestration - SUMMARY AND RECOMMENDATIONS
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●Definition and types– Bronchopulmonary sequestration (BPS) is a rare congenital abnormality of the lower respiratory tract. It consists of a nonfunctioning mass of lung tissue that lacks normal communication with the tracheobronchial tree and receives its arterial blood supply from the systemic circulation. The connections to the tracheobronchial tree and systemic artery distinguishes BPS from congenital pulmonary airway malformation (CPAM). (See'Anatomic characteristics'above.)
•An intralobar sequestration (ILS) is located within a normal lobe and lacks its own visceral pleura. This type often has aberrant connections to bronchi, lung parenchyma, or the gastrointestinal tract and often presents with recurrent infections.
•An extralobar sequestration (ELS) is located outside the normal lung and has its own visceral pleura. Infectious complications are rare, except in ELS with connections to the gastrointestinal tract or intrapulmonary structures, which is unusual.
●Associated anomalies– Congenital abnormalities that are sometimes associated with BPS include congenital diaphragmatic hernia, vertebral anomalies, congenital heart disease, pulmonary hypoplasia, colonic duplication, and CPAM. These associated anomalies are more common in ELS compared with ILS. (See'Associated anomalies'above.)
●Clinical presentation– The clinical presentation of BPS is variable and depends on the type, size, and location of the lesion. Many cases are initially detected by prenatal ultrasound; most of these regress during gestation, while others progress and hydrops may develop. The affected newborn is usually asymptomatic but sometimes presents with respiratory distress. Some cases (usually ILS) present with recurrent pneumonia during infancy or childhood. (See'Clinical presentation'above.)
●Postnatal evaluation– All cases of BPS or other congenital abnormalities of the lower airway should be further evaluated with postnatal imaging. This includes cases that regressed or appeared to resolve in utero because few lesions resolve completely and advanced imaging is more sensitive than prenatal ultrasound for detecting small lesions. (See'Postnatal imaging'above.)
•After birth, the first step is a plain chest radiograph. On a chest radiograph, sequestrations typically appear as a uniformly dense mass within the thoracic cavity or pulmonary parenchyma (image 4). Recurrent infection can lead to cystic areas within the mass, and there may be air-fluid levels if the lesion communicates with a bronchus.
•The second step is advanced thoracic imaging, the timing of which depends on the patient's characteristics, as outlined in the algorithm (algorithm 1). This is to confirm the diagnosis, including identifying the aberrant artery that distinguishes BPS, and to help with surgical planning.
●Management
•Symptomatic– Infants with BPS that is causing any respiratory symptoms (respiratory distress or tachypnea) are treated with surgical excision; surgery is curative and is associated with minimal morbidity. The procedure is performed urgently in newborns with significant respiratory distress. Surgical resection is typically performed electively in older children who present with infection. (See'Symptomatic patients'above.)
•Asymptomatic,high risk– For asymptomatic patients of any age with characteristics that suggest a high risk for developing complications (large lesions occupying >20 percent of the hemithorax, bilateral or multifocal cysts, pneumothorax, or a family history of pleuropulmonary blastoma-associated conditions (table 1)), we suggest surgical resection rather than observation (Grade 2C). (See'High risk'above.)
•Asymptomatic, low risk– For asymptomatic patients without these high-risk characteristics, either elective surgical resection or conservative management with observation are reasonable options and practice varies (algorithm 1). (See'Low risk'above.)
-In our practice, we generally perform surgery for all asymptomatic infants with BPS, regardless of the lesion's size and characteristics. The surgery is elective and is usually performed between 6 and 12 months of age. Our preference for surgery is based on the good outcomes after surgery and on the risk of developing complications (primarily infection) if surgery is not performed. The likelihood and risk factors for developing complications if surgery is not performed are poorly delineated. (See'Outcome'above.)
-Other authors prefer to observe asymptomatic patients, especially if the lesion is small, noncystic, and appears to be consistent with ELS. Optimal surveillance strategies for observation have not been determined.
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - SUMMARY AND RECOMMENDATIONS
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●Overview– Early lung injury in infancy due to bronchopulmonary dysplasia (BPD) can have lifelong consequences, manifested by altered pulmonary function, upper and lower airway disease, and pulmonary hypertension (PH). Infants with extremely low birth weight (ELBW; birth weight <1000 g) are especially vulnerable. (See'Respiratory disorders associated with bronchopulmonary dysplasia'above.)
●Pathogenesis of BPD– In the modern era, the most important feature of BPD is impaired alveolar development, with decreased septation and alveolar hypoplasia leading to fewer and larger alveoli and dysmorphic pulmonary vasculature. The lungs often undergo "catch-up" alveolar growth throughout infancy and childhood, so that many affected individuals develop nearly normal lung function and pulmonary reserve with time.
In infants who were born before the advent of modern neonatal intensive care unit management techniques, BPD is typically characterized by airway injury with inflammation and alveolar septal fibrosis, known as "classic" BPD. These changes are usually associated with oxygen toxicity, barotrauma/volutrauma, and infection. (See'New versus classic bronchopulmonary dysplasia'above.)
●Issues arising during long-term management
•General care– To optimize lung function, it is important to minimize lung injury by avoiding recurrent respiratory infections, minimize feeding-related aspiration, and optimize nutrition, particularly during the first two years of life. (See'General measures'above.)
•Asthma-like symptoms– Recurrent wheezing episodes are common in children and adolescents with a history of BPD, but the underlying pathophysiology differs from asthma. If spirometry suggests obstructive lung disease, a trial of standard asthma management techniques is appropriate. Bronchodilators are effective in approximately one-half of these patients. Similarly, children with BPD may respond to inhaled corticosteroids, but the effect is less consistent than in children with asthma. In general, the use of bronchodilators and inhaled corticosteroids should be limited to specific subgroups of patients with BPD, based on European and American guidelines. (See'Asthma and asthma-like symptoms'above.)
•Associated PH– All infants with moderate or severe BPD should be screened for PH using echocardiography. For most infants, the initial echocardiogram should be performed at the time the formal diagnosis of BPD is made. Earlier screening should be performed for selected infants with severe respiratory symptoms or risk factors, or if an anesthetic procedure is planned, because PH is associated with increased risk of complications during anesthesia. (See"Pulmonary hypertension associated with bronchopulmonary dysplasia", section on 'Screening'.)
•Central airway disease– Infants with BPD, and especially those with "classic" BPD, are at risk for central airway collapse due to tracheobronchomalacia, which can exacerbate underlying thoracic airway disease. Clinical manifestations include "BPD spells" (cyanotic or life-threatening episodes), chronic wheezing unresponsive to bronchodilator therapy, propensity for atelectasis, and long-term dependence on mechanical ventilation and/or tracheostomy. (See'Central airway disease'above.)
ACKNOWLEDGMENT— The UpToDate editorial staff acknowledges Leslie L Harris, MD, and James M Adams, Jr, MD, who contributed to an earlier version of this topic review.
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - INTRODUCTION
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Despite important advances in perinatal care and a steady decline in mortality rates among very low birth weight (VLBW) infants (<1500 g) during the past two decades, bronchopulmonary dysplasia (BPD) remains a major complication of premature birth and is a significant cause of long-term morbidity. Prematurity and low birth weight remain major risk factors for the development of BPD [1]. Other contributors to the development of chronic lung injury include swallowing dysfunction and poor nutrition, which are common comorbidities in infants born very prematurely. Because of its chronic nature and multifactorial causes, many infants and children with BPD will require multifaceted and multidisciplinary management well beyond the first year of life. Limited guidelines for the management of BPD after initial discharge from the hospital have been published by both the European Respiratory Society and the American Thoracic Society [2,3].
The long-term consequences of BPD on the respiratory health of older children and adults are not fully described, especially because new developments in the care of premature infants have resulted in important changes in the clinical and pathologic characteristics of BPD during more recent decades. Although BPD tends to improve with advancing age, it can lead to lifelong consequences [4,5].
The long-term pulmonary outcomes of BPD are reviewed here. Other aspects of BPD are discussed in separate topic reviews:
Diagnosis and management of BPD during infancy:
●(See"Bronchopulmonary dysplasia (BPD): Clinical features and diagnosis".)
●(See"Bronchopulmonary dysplasia (BPD): Prevention".)
●(See"Bronchopulmonary dysplasia (BPD): Management and outcome".)
●(See"Pulmonary hypertension associated with bronchopulmonary dysplasia".)
Long-term outcomes and management of nonpulmonary problems associated with BPD:
●(See"Care of the neonatal intensive care unit graduate".)
●(See"Growth management in preterm infants".)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - DEFINITION
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A commonly used definition of BPD is the need for supplemental oxygen or positive pressure support for more than 28 days, with severity defined by further criteria depending on gestational age [1]. More recently, a National Institutes of Child Health and Human Development working group revisited this definition to include newer forms of respiratory support (eg, high-flow nasal cannula and other forms of noninvasive ventilation) that were not in common use at the time when the earlier definition was published (table 1) [6]. (See"Bronchopulmonary dysplasia (BPD): Clinical features and diagnosis", section on 'Definitions and severity of BPD'.)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - DEFINITION - New versus classic bronchopulmonary dysplasia
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The clinical and histologic features of BPD have changed with the advent of new technologies and approaches to care, including surfactant administration, permissive hypercapnia, and noninvasive ventilation. This has led to increased survival of extremely low birth weight (ELBW) infants and the evolution of a new type of BPD, with different pathogenesis and clinical features as compared with the classic form of BPD (see The clinical and histologic features of BPD have changed with the advent of new technologies and approaches to care, including surfactant administration, permissive hypercapnia, and noninvasive ventilation. This has led to increased survival of extremely low birth weight (ELBW) infants and the evolution of a new type of BPD, with different pathogenesis and clinical features as compared with the classic form of BPD (see "Bronchopulmonary dysplasia (BPD): Clinical features and diagnosis", section on 'Pathology' ):
●New BPD– The primary characteristic of BPD is impaired alveolar development, due to very premature birth and ELBW. Survival of these infants became more possible after the advent of antepartum glucocorticoid use and surfactant treatment. Interestingly, some infants born very prematurely have little or no respiratory distress at birth but develop a need for supplemental oxygen and/or positive pressure support by 36 weeks postmenstrual age. BPD in these infants can occur despite strategies used to minimize lung injury. The pathophysiology that develops in these preterm infants is often referred to as "new" BPD [7]. The lungs are characterized by fewer and larger alveoli and dysmorphic pulmonary vasculature [8]. Dysregulation of signaling pathways, which are integral to lung development, likely contribute to the pathologic changes that are seen in the BPD lung [9].
The incidence of new BPD has not changed over the past two decades, despite advances in care, due in part to increased survival of infants born at less than 28 weeks gestation [10,11]. However, the advent of newer management strategies in the neonatal intensive care unit setting, such as less invasive surfactant administration, may lead to further improvements in outcomes [12].
●Classic BPD– Before the advent of surfactant and more modern management techniques, the most prominent features of BPD were airway injury, inflammation, and alveolar septal fibrosis. These changes were usually associated with oxygen toxicity, barotrauma, and infection. This type of pathophysiology is sometimes termed "classic" or "old" BPD. This form of BPD is uncommon in the post-surfactant era but is still occasionally seen, particularly in infants with BPD requiring long-term mechanical ventilation.
Infants with classic BPD and who required prolonged mechanical ventilation were prone to develop severe tracheobronchomalacia, which often caused profound cyanotic episodes [13]. When these individuals reach adulthood, some have interstitial and emphysematous changes detected by chest radiography and computed tomography [14]. It is likely that some of these adults will have a predisposition to accelerated loss of lung function or early-onset chronic obstructive pulmonary disease as they enter middle age; therefore, they should be followed closely throughout life for decline in lung function [15].
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - PULMONARY FUNCTION
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Abnormalities in pulmonary function tests (PFTs) are commonly found in children and adults with BPD [4,16-18]. PFTs frequently show decreased forced expiratory volume in one second (FEV1) and decreased ratios of FEV1to forced vital capacity (FEV1/FVC), consistent with airflow limitation and small airway obstruction [16,17]. The airflow limitation may be a consequence of dysanaptic growth, in which length and diameter of the airways grow less rapidly than the lung parenchyma, which in turn can cause fixed airflow obstruction [19-22].However, many children with BPD also have a reactive component to their obstructive lung disease, as demonstrated by their clinical response to steroids and bronchodilators[23].(See'Asthma-like symptoms'below.)
Chemoreceptor sensitivity has been shown to be abnormal in the child with BPD, and these changes can persist into adulthood [24,25]. Infants with BPD may manifest an inability to increase their ventilatory response to hypoxia. The mechanisms are multifactorial and may include abnormalities in the peripheral and central chemoreceptor response to hypoxia, and/or to abnormal respiratory muscle function [24]. Furthermore, infants with BPD often fail to exhibit a normal decrease in ventilation in response to a hyperoxia challenge [26]. A study performed in 20 school-aged children with BPD found that 60 percent hypoventilated during exercise and developed hypoxemia and hypercapnia, in contrast with healthy controls [27].
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - PULMONARY FUNCTION - Infancy
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PFTs during infancy are not routinely performed in most centers but can be useful when available in tracking changes in pulmonary function, response to bronchodilators and diuretics, and overall severity of disease, particularly in infants not responding well to supportive treatment [ PFTs during infancy are not routinely performed in most centers but can be useful when available in tracking changes in pulmonary function, response to bronchodilators and diuretics, and overall severity of disease, particularly in infants not responding well to supportive treatment [ 28 ].
In one study of preterm infants approximately six months of age with severe BPD, all had abnormalities on PFTs, with three distinct phenotypes (51 percent obstructive, 40 percent mixed, and 9 percent restrictive) [29]. Several studies in older infants (6 to 12 months) with BPD have demonstrated evidence of small airway disease and impaired alveolar growth. Gas trapping and small airway disease was suggested by decreased maximum expiratory flow at functional residual capacity (VmaxFRC)and low functional to total lung volume ratios (FRCHe/FRCpleth); impaired alveolar growth was suggested by elevated partial pressure of carbon dioxide in arterial blood (PaCO2) and increased alveolar-to-arterial gradient [30-32].
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - PULMONARY FUNCTION - Early childhood
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For young children (three to six years of age) who are not able to perform conventional spirometry, impulse oscillometry is an emerging modality for measuring lung function. Testing does not require sedation, may show increases in respiratory impedance and small airway resistance in individuals with airflow obstruction, and may help direct therapy [ For young children (three to six years of age) who are not able to perform conventional spirometry, impulse oscillometry is an emerging modality for measuring lung function. Testing does not require sedation, may show increases in respiratory impedance and small airway resistance in individuals with airflow obstruction, and may help direct therapy [ 33 ]. It is unknown whether observed changes are associated with long-term outcomes beyond six to seven years of age [ 34 ].
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - PULMONARY FUNCTION - Childhood
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PFTs in older children, adolescents, and adults are widely available and are useful in following longitudinal changes in pulmonary function. Spirometry may be the most useful PFT in detecting lung abnormalities in extremely premature children, including those with BPD [ PFTs in older children, adolescents, and adults are widely available and are useful in following longitudinal changes in pulmonary function. Spirometry may be the most useful PFT in detecting lung abnormalities in extremely premature children, including those with BPD [ 35 ]. In some centers, spirometry can be performed in children as young as three years of age [ 36 ]; however, most PFT laboratories begin testing children at six years of age. Both pre- and post-administration of inhaled bronchodilators can be used to test for airway reactivity. Unfortunately, some children with BPD have cognitive difficulties that preclude their ability to perform PFTs. As a result, studies may underestimate the number of children who have abnormal lung function. (See "Overview of pulmonary function testing in children" .)
Although clinical symptoms in individuals with BPD often improve during childhood, PFTs often remain abnormal, particularly in those with more severe disease [37-39]. One study compared preschool children with healthy controls and found decreased FEV1, increased FRC, residual volume (RV), and the ratio of RV to total lung capacity (RV/TLC) in the BPD group, consistent with obstructive lung disease [40]. These findings are consistent with persistent airflow obstruction and gas trapping.
While lung function is markedly abnormal in infancy for most infants with BPD [19], it can improve during childhood, such that many patients born preterm may have normal lung function in early adult life [41]. Nonetheless, BPD or extremely low birth weight remain risk factors for poorer or deteriorating lung function in preadolescence, adolescence, and young adult life for some patients [16,42-44], and patients with moderate to severe BPD are more likely to have ongoing impairment [20,45-47]. The deteriorating lung function is usually obstructive in nature but may have a restrictive component in some cases.
Improvements in PFTs over time have been shown in several studies. In one study, sequential measurements during the first two to three years following hospital discharge demonstrated gradual increases in FRC (mL/kg) from initial low levels to more normal levels but with persistent limitations of maximum flow at FRC (VmaxFRC) [46]. Approximately one-third of these patients responded to bronchodilators. Another study reported improvements in lung compliance (from 50 percent of normal at one month of age to 80 percent of normal at 36 months) and specific pulmonary conductance (from 50 percent of normal at one month to 85 percent of normal at 36 months) [47]. In a third study, forced expiratory flow at two years of age was closely related to forced expiratory flow at eight years, suggesting little recovery of the airways [21].
Prematurity itself is a dominant risk factor for lung injury and long-term impairment of pulmonary function. Whether or not BPD exists, the risk is compounded by postnatal lung injury [48,49]. One series reported lung function in 48 children who were born at very low birth weight (VLBW) and managed at a tertiary center after the introduction of surfactant therapy [50]. At 8.5±1.0 years, VLBW children had significantly lower FVC, FEV1, and carbon monoxide diffusion capacity (DLCO) as compared with 46 age-matched controls. No differences were found between the VLBW children with or without BPD except for a higher RV/TLC ratio in the BPD subgroup (mean difference 7 percent; 95% CI 0.4-13 percent; p = 0.03). In a similar report, 53 extremely low birth weight (ELBW) infants (28 with BPD and 25 without BPD) were compared with 23 term controls at 10±1 years of age [51]. FEV1was significantly lower in the ELBW group (85±10 percent versus 94±10 percent, p<0.001), with limited reversibility by bronchodilators. Likewise, RV/TLC and DLCO differed significantly. These measurements did not differ in ELBW subgroups with or without BPD. In a separate longitudinal cohort of extremely preterm infants studied at six years of age, FVC and FEV1values were significantly lower, and frequency-dependence of resistance was significantly greater than in controls who were born at term [34]. Asthma-like symptoms were present in 40 percent of children who were born extremely preterm, compared with 15 percent of the control children.
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - PULMONARY FUNCTION - Adults with classic bronchopulmonary dysplasia
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Long-term abnormalities in pulmonary function and respiratory symptoms have been reported in individuals with the classic form of BPD [ Long-term abnormalities in pulmonary function and respiratory symptoms have been reported in individuals with the classic form of BPD [ 23,52-56 ]. In a study of 147 adolescents born weighing less than 1500 g in the period 1977 to 1982, PFTs at a mean of 18.9 years demonstrated clinically significant reduction in airflow and deterioration in pulmonary function since the previous evaluation at eight years of age [ 16 ]. Similarly, long-term studies in children ages 6 to 15 years with BPD found persistent airway obstruction, airway hyperreactivity, and hyperinflation of the lungs [ 23,52-54,57-75 ]. Both vital capacity and FEV 1 were reduced as compared with control subjects [ 28 ]. The duration of oxygen dependence in the neonatal period may predict respiratory morbidity during early childhood [ 76 ] and possibly the long-term pulmonary outcome [ 77,78 ]. These studies reflect in part the management of premature infants 20 years ago; much less is known regarding the long-term outcome of infants managed with modern neonatal intensive care unit strategies.
Only a few studies have compared long-term outcomes of early versus late cohorts (ie, classic BPD versus new BPD). In one study, long-term pulmonary function was evaluated in two groups of subjects that were initially managed in a neonatal intensive care unit in Norway [79]. The first group was born between 1982 and 1985, prior to the use of surfactant. The second group was born between 1991 and 1992 when surfactant was used as rescue therapy for respiratory distress syndrome. As adolescents, the mean FEV1was similar between the two groups of children with BPD (81.9 and 80.8 percent predicted) and was lower than the control groups born at term during the same time periods. In a separate systematic review and meta-analysis, long-term outcomes (measured by FEV1percent predicted) for children born preterm who required supplemental oxygen at 28 days of life were substantially better for children born during the 1990s compared with earlier decades [80].
Another study measured long-term pulmonary function outcomes in individuals between 10 and 35 years of age. Although pulmonary function deficits were found in those born extremely preterm compared with those born term, these pulmonary deficits decreased with each decade of birth from 1980 to 2000 [44], suggesting that ongoing improvements in care may be able to mitigate pulmonary function deficits in children and adults born extremely preterm.
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - RESPIRATORY DISORDERS ASSOCIATED WITH BRONCHOPULMONARY DYSPLASIA
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BPD may include parenchymal lung disease, pulmonary hypertension (PH), and large airway disease. These disorders are often not found in isolation, particularly with severe disease. A study found that nearly three-quarters of infants with severe BPD had two or more of these manifestations [81].
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - RESPIRATORY DISORDERS ASSOCIATED WITH BRONCHOPULMONARY DYSPLASIA - Asthma-like symptoms
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Recurrent wheezing episodes are very common in children with BPD, beginning in the preschool years and continuing into adulthood [ Recurrent wheezing episodes are very common in children with BPD, beginning in the preschool years and continuing into adulthood [ 4,16,82-84 ]. Adolescents also experience reduced exercise tolerance, impaired ventilatory adaptation [ 53,73,85 ], and reduced gas transfer during physical activity [ 53,71,86 ]. As an example, in the EPICure study of children born less than 26 weeks gestation, 25 percent of children had the diagnosis of asthma at 11 years of age and 56 percent had abnormal spirometry [ 87 ]. In other studies, the odds of being assigned a diagnosis of "asthma" is three- to fourfold more likely in infants born less than 32 weeks gestation compared with the general population [ 34,88 ].
Although children with BPD have asthma-like symptoms, they are less likely to have the airway hyperresponsiveness that characterizes asthma and less likely to respond to bronchodilators compared with children with no history of BPD. Only 40 to 50 percent of children with BPD demonstrate significant airway hyperresponsiveness to exercise, histamine ormethacholine, or a significant response to bronchodilator administration [89,90]. Indeed, in some infants with central airway disease (tracheobronchomalacia), bronchodilators may exacerbate wheezing [28,91]. Similarly, children with BPD may respond to inhaled corticosteroids, but the effect is less consistent than in children with asthma [28,92-94].
BPD and asthma also differ in underlying pathophysiology. The lung of the older child and adult recovered from BPD can demonstrate airway wall thickening similar to individuals with asthma. However, in addition, there are morphologic changes noted on computed tomography scans of the chest, including linear and triangular opacities, mosaic perfusion, and air trapping [95], which can be compatible with a diagnosis of fixed peripheral airway narrowing. Unlike children with asthma, children with airway hyperreactivity due to BPD may not have elevated levels of exhaled nitric oxide (a marker for eosinophil-driven inflammation) [21,96] or an increased incidence of atopy [4].
Environmental factors, including tobacco smoke exposure, indoor air pollution, traffic-related pollution, and environmental allergens, may contribute to the pulmonary function abnormalities and respiratory outcomes [82,97-99]. It has been shown that very low birth weight (VLBW) infants who live with a smoker are significantly more likely to require acute care for respiratory symptoms than VLBW infants who are not exposed [100]. Preterm infants may also be susceptible to thirdhand smoke exposure. This is suggested by a study that detected nicotine metabolites in infants within a neonatal intensive care unit setting after visits from household members who smoke [101]. Among individuals with extremely low birth weights (ELBWs; <1000 g), those who smoked during adolescence were more likely to experience a decline in pulmonary function during adolescence as compared with nonsmokers [102]. Limited data from murine models suggest that exposure to nicotine-containing electronic cigarette vapor can adversely affect lung growth and reduce mucociliary clearance compared with nonexposed mice [103,104].
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - RESPIRATORY DISORDERS ASSOCIATED WITH BRONCHOPULMONARY DYSPLASIA - Pulmonary hypertension
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PH, a condition characterized by elevated pulmonary artery pressure, develops in 20 to 40 percent of infants with BPD [ PH, a condition characterized by elevated pulmonary artery pressure, develops in 20 to 40 percent of infants with BPD [ 105-107 ]. The risk for PH is highest in very premature and VLBW infants, as well as those with cardiovascular anomalies. At a minimum, all infants with moderate or severe BPD should be screened for PH using echocardiography [ 108,109 ]. Earlier screening should be performed for selected infants with severe respiratory symptoms or risk factors, or if an anesthetic procedure is planned, because PH is associated with increased risk of life-threatening complications during anesthesia. Screening procedures and management of PH in this population are discussed separately. (See "Pulmonary hypertension associated with bronchopulmonary dysplasia" .)
Infants surviving the initial stages of PH often experience improvement or resolution of the PH due to catch-up lung growth and development [110]. However, there may be subpopulations of infants with BPD who have chronic PH lasting years even if respiratory symptoms are improving [111,112]. (See"Pulmonary hypertension associated with bronchopulmonary dysplasia", section on 'Epidemiology and natural history'.)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - RESPIRATORY DISORDERS ASSOCIATED WITH BRONCHOPULMONARY DYSPLASIA - Central airway disease
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The central airways span the glottis to the lobar or segmental bronchi. Acquired damage to the airways in infancy may persist into early childhood and beyond. Infants and young children with BPD are at increased risk of developing central airway collapse or obstruction, which can lead to "BPD spells" or cyanotic or life-threatening episodes, chronic wheezing unresponsive to bronchodilator therapy, recurrent atelectasis, lobar emphysema, or failure to wean from mechanical ventilation or to tolerate tracheal extubation [ The central airways span the glottis to the lobar or segmental bronchi. Acquired damage to the airways in infancy may persist into early childhood and beyond. Infants and young children with BPD are at increased risk of developing central airway collapse or obstruction, which can lead to "BPD spells" or cyanotic or life-threatening episodes, chronic wheezing unresponsive to bronchodilator therapy, recurrent atelectasis, lobar emphysema, or failure to wean from mechanical ventilation or to tolerate tracheal extubation [ 28 ]. There has been increased use of gabapentin to treat BPD spells and neonatal irritability in infants with severe BPD [ 113 ]; however, efficacy of use in this population has not been established. In one study of preterm infants with large airway malacia, up to 30 percent required tracheostomy placement [ 114 ]. (See 'Tracheostomy' below.)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - RESPIRATORY DISORDERS ASSOCIATED WITH BRONCHOPULMONARY DYSPLASIA - Central airway disease - -Acquired tracheobronchomalacia
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This complication of BPD was more common in infants and children with classic BPD who were treated with prolonged positive pressure ventilation (PPV). Tracheobronchomalacia is characterized by abnormally compliant, collapsible central airways and may be a consequence of barotrauma, chronic or recurrent infection, chronic aspiration, and endotracheal intubation. This complication of BPD was more common in infants and children with classic BPD who were treated with prolonged positive pressure ventilation (PPV). Tracheobronchomalacia is characterized by abnormally compliant, collapsible central airways and may be a consequence of barotrauma, chronic or recurrent infection, chronic aspiration, and endotracheal intubation.
Tracheobronchomalacia can improve with age, as the tracheal cartilage matures and becomes less compliant [115-118]. Nonetheless, it has been noted in patients with BPD as old as 35 months [119-124]. (See"Congenital anomalies of the intrathoracic airways and tracheoesophageal fistula", section on 'Tracheomalacia'.)
Symptoms of tracheobronchomalacia may include "BPD spells" or reflex apnea (episodes of abrupt cyanosis with absent airflow that may be life-threatening) during infancy. Affected infants and children may also have chronic wheezing that does not improve or worsens with bronchodilator therapy or increased work of breathing [28]. The symptoms typically increase with crying or exertion. Tracheobronchomalacia may also be associated with poor growth as these infants may have increased caloric needs due to work of breathing [125]. In severe cases, management may require tracheostomy [81].
In one study of infants with classic BPD, tracheomalacia was found in 45 percent of those undergoing bronchoscopy and bronchomalacia was found in 34 percent [126]. In the post-surfactant era, however, acquired tracheobronchomalacia appears to be less common. This is likely due to the more prudent use of PPV and noninvasive ventilatory techniques. Although the prevalence of large airway malacia is reported to be low (2 percent) among preterm infants [114], central airway disease may be underdiagnosed because relatively few preterm infants undergo bronchoscopy [127].
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - RESPIRATORY DISORDERS ASSOCIATED WITH BRONCHOPULMONARY DYSPLASIA - Central airway disease - -Glottic and subglottic damage
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Injury to the glottis and surrounding structures has been reported after endotracheal intubation in newborns [ Injury to the glottis and surrounding structures has been reported after endotracheal intubation in newborns [ 128-137 ]. This can occur more commonly in ELBW infants who require prolong PPV with an endotracheal tube. Epithelial damage after endotracheal intubation is a common occurrence [ 132,134 ], but most superficial lesions resolve without further sequelae [ 129,130,136 ]. Acquired subglottic stenosis and laryngeal injury are seen more often in infants who have been intubated for a week or longer and who required three or more intubations [ 128,129,136 ]. The use of inappropriately large endotracheal tubes has also been implicated [ 128,136,137 ].
Postextubation stridor is the most common sign of moderate to severe subglottic stenosis or laryngeal injury [128,136]. The child may have chronic symptoms or exhibit symptoms only during acute upper respiratory tract infections. Children with BPD and stridor should be evaluated endoscopically to determine the level and cause of airway obstruction. (See"Assessment of stridor in children".)
Children with severe subglottic stenosis may require tracheostomy for management. Decannulation may be possible as the child grows larger or after reconstructive surgery. (See'Tracheostomy'below.)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - RESPIRATORY DISORDERS ASSOCIATED WITH BRONCHOPULMONARY DYSPLASIA - Central airway disease - -Tracheal and bronchial stenosis and granuloma formation
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Acquired tracheal or bronchial stenosis or granuloma formation has been reported in a subset of infants with BPD as old as 17 months [ Acquired tracheal or bronchial stenosis or granuloma formation has been reported in a subset of infants with BPD as old as 17 months [ 119,120,126,138-142 ]. Stenosis and granulation formation are probably not the result of lung disease itself but rather the result of trauma from artificial airways and suctioning techniques [ 143-146 ]. These injuries can cause long-term pulmonary problems, including acquired lobar emphysema or persistent lobar atelectasis, depending on the degree of luminal obstruction. Lobar overdistension occurs when a partial obstruction allows air to enter the lung distal to the lesion on inspiration but prevents egress of air on exhalation (ball-valve mechanism); lobar atelectasis can develop if the obstruction is complete on both phases of respiration. These complications are seen much less frequently since the practice of "deep suctioning" (passing a suction catheter until resistance is felt, then applying suction to the airway) has been abandoned by most neonatal units.
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - RESPIRATORY DISORDERS ASSOCIATED WITH BRONCHOPULMONARY DYSPLASIA - Sleep-disordered breathing
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Patients with a history of BPD are at increased risk for sleep-disordered breathing. Accordingly, polysomnography is recommended for infants, children, and adolescents with a history of BPD and symptoms of sleep-disordered breathing, including persistent snoring, failure to thrive, or persistent need for supplemental oxygen at two years of age, as outlined in a guideline from the American Thoracic Society [ Patients with a history of BPD are at increased risk for sleep-disordered breathing. Accordingly, polysomnography is recommended for infants, children, and adolescents with a history of BPD and symptoms of sleep-disordered breathing, including persistent snoring, failure to thrive, or persistent need for supplemental oxygen at two years of age, as outlined in a guideline from the American Thoracic Society [ 3 ].
Studies suggest that children with a history of prematurity may be more likely to have obstructive sleep apnea compared with the general population both as toddlers [147-149] and later in childhood [150,151]. This may persist into adulthood as chronic snoring is more common in young adults with a history of premature birth [152]. In addition, other factors predict the type of sleep-disordered breathing; in one study of young children with a history of prematurity, central apnea events were more common among participants who had more severe underlying BPD or who were White, while obstructive apnea was more common among African American or biracial participants [149].
Childhood obstructive sleep apnea is associated with deficits of cognitive and executive function and possible neuronal injury as reflected by proton magnetic resonance spectroscopic imaging [153]. Thus, untreated obstructive sleep apnea could potentially contribute to developmental delays, which are already common in infants and children with a history of prematurity. (See"Cognitive and behavioral consequences of sleep disorders in children", section on 'Sleep-related breathing disorders'.)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - RESPIRATORY DISORDERS ASSOCIATED WITH BRONCHOPULMONARY DYSPLASIA - Sleep hypoxemia
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Infants with a history of BPD are more likely to experience hypoventilation and hypoxemic episodes during sleep [ Infants with a history of BPD are more likely to experience hypoventilation and hypoxemic episodes during sleep [ 154-158 ], and these episodes may be clinically silent [ 155 ]. Many infants and children with severe BPD still require nighttime supplemental oxygen after neonatal intensive care unit discharge. Overnight polysomnography can be helpful determining the optimal time of weaning off supplemental oxygen during sleep [ 147 ].
Episodes of desaturation are more common during rapid eye movement (REM) sleep [155] when intercostal and upper airway muscle tone is reduced, leading to a reduction in both functional residual capacity (FRC) and upper airway resistance. The former leads to further closure of narrowed airways as FRC falls below closing volume, thereby producing an increase in low V/Q regions. Arousal due to hypoxemia appears to be age-dependent but may lead to decreased sleep time during REM sleep in these infants [159,160]. Other contributing factors that may play a role include inadequate autonomic response mechanisms [161] and hypoxemia-induced airway narrowing [162]. Exposure to secondhand smoke in the home may exacerbate this problem [149].
Hypoxemic episodes during sleep can also affect older children. In one study of patients aged three to five years with severe BPD, multiple prolonged episodes of desaturation occurred during sleep, especially during REM sleep, despite adequate oxygen saturation when awake [163]. In another study of 17 children (mean age nine years), there were similar findings [164]. Increased thoraco-abdominal asynchrony during sleep has also been found in children with severe BPD (age range 19 to 46 months) [165]. Sleep-related hypoxemia may also lead to decreased biventricular function [166] and impaired autonomic heart rate control in these children [167]. The incidence of sleep disordered breathing is greater in school-age children with a history of prematurity, but not necessarily of BPD, compared with those born at term [168].
Sleep hypoxemia is associated with growth delay in infants with BPD [169]. The clinical consequences of sleep hypoxemia in older children with BPD has not been established, but there may be an effect on cognitive development, as has been found in children with sleep-disordered breathing and intermittent hypoxia [153]. (See'Sleep-disordered breathing'above.)
The management of infants with evidence of sleep hypoxemia is discussed separately. (See"Bronchopulmonary dysplasia (BPD): Management and outcome", section on 'Supplemental oxygen'.)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - RESPIRATORY DISORDERS ASSOCIATED WITH BRONCHOPULMONARY DYSPLASIA - Respiratory infection
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Up to 50 percent of children with BPD require rehospitalization during the first two years of life due to a respiratory illness [ Up to 50 percent of children with BPD require rehospitalization during the first two years of life due to a respiratory illness [ 170,171 ]. These infections, which are usually due to viruses, may interfere with early postnatal lung growth and can adversely affect lung function in later life [ 172 ]. Compared with children without BPD admitted with respiratory viral illnesses, those with BPD are more likely to experience in-hospital complications and mortality [ 173 ]. Respiratory infections, including respiratory syncytial virus (RSV), can cause particularly severe illness in infants and children with BPD, contribute to high rates of rehospitalization, and can be life-threatening [ 174 ]. This is especially true for those infants who still require supplemental oxygen at the time of infection [ 175 ]. Furthermore, children with BPD who had been hospitalized with an RSV infection within the first two years of life have increased health care costs and worse lung function at school age than those who did not experience an RSV-related hospitalization [ 172 ]. Increasing evidence suggests that children with a history of BPD may have alterations in airway microbiome and lymphocyte-related immunity that may influence their response to respiratory infections [ 176 ]. For these reasons, infants and children with BPD may require additional immunizations and immunoprophylaxis for RSV. (See "Respiratory syncytial virus infection: Prevention in infants and children" and "Care of the neonatal intensive care unit graduate", section on 'Immunizations' .)
Rhinovirus infection is extremely common in the general population. Although it predominately causes upper airway symptoms in healthy individuals, severe lower respiratory tract disease can occur in children with BPD [177-179]. Individuals born with ELBW remain at increased risk for complications from these and other respiratory viruses and for respiratory-related hospitalization during adolescence [180,181]. Of note, daycare attendance among infants and young children with BPD has been associated with a two- to threefold increase in emergency department visits, systemic corticosteroid use, antibiotic use, and days with difficulty breathing, which may be due to increased exposure to infectious illnesses [182].
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - RESPIRATORY DISORDERS ASSOCIATED WITH BRONCHOPULMONARY DYSPLASIA - Obstructive lung disease in adulthood
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Several studies have reported that adults with a history of BPD are more likely to exhibit airflow obstruction compared with controls [ Several studies have reported that adults with a history of BPD are more likely to exhibit airflow obstruction compared with controls [ 56,183 ]. As an example, a cohort of adults who were born with VLBW had significantly lower forced expiratory volume in one second (FEV 1 ) and FEV 1 /forced vital capacity (FVC) compared with term controls, and the subset with BPD had the lowest values [ 183 ]. Other studies suggest that dysanaptic airway growth (resulting in smaller airways relative to lung size) may be responsible for the observed airflow obstruction. In a retrospective study, young adults with VLBW, and particularly those with BPD, were more likely to have dysanaptic airways compared with term controls [ 184 ]. A separate report found that dysanaptic airways are a predictor of chronic obstructive pulmonary disease, independent of smoking status [ 185 ].
These observations raise the possibility that individuals with VLBW and BPD are at increased risk for developing chronic obstructive pulmonary disease as they age. However, the few available studies on respiratory outcomes in adults with BPD may not reflect the neonatal interventions that are currently being used to mitigate lung injury in VLBW infants. Longitudinal functional and structural studies of the lungs are needed to better understand risk factors for and prevalence of respiratory diseases in adults with a history of BPD and/or VLBW.
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - MANAGEMENT AFTER NEONATAL INTENSIVE CARE UNIT DISCHARGE
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Children, adolescents, and young adults with BPD may be followed up in a number of outpatient clinic settings. These include a pediatrician's office or a hospital-based follow-up clinic. In either case, the patient should be referred to a pulmonologist familiar with the care of these often medically fragile patients. Those with complex medical problems should optimally be managed by a team of subspecialists familiar with BPD, in addition to a pulmonologist and a general pediatrician [186]. (See"Care of the neonatal intensive care unit graduate".)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - MANAGEMENT AFTER NEONATAL INTENSIVE CARE UNIT DISCHARGE - General measures
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The following measures are appropriate for all infants and children with a history of BPD to reduce their risk for respiratory disease: The following measures are appropriate for all infants and children with a history of BPD to reduce their risk for respiratory disease:
●Close adherence to immunization schedules recommended for premature infants, especially RSV prophylaxis and influenza virus vaccines. Coronavirus disease 2019 (COVID-19) vaccinations should be given in an age-appropriate manner in children and adolescents with BPD. Caregivers should be conscientious about frequent handwashing and avoid exposing the infant and young child to respiratory infections. (See"Respiratory syncytial virus infection: Prevention in infants and children"and"Care of the neonatal intensive care unit graduate", section on 'Immunizations'and'Respiratory infection'above and"COVID-19: Vaccines".)
●Individualized advice to parents regarding daycare attendance, with reference to the age of the child, severity of lung disease, and seasonal prevalence of respiratory infectious diseases [2].
●Strict avoidance of tobacco smoke and electronic cigarette exposure. It is important to eliminate all smoking within the home, car, and daycare setting; intermediate measures to limit a child's exposure are not very effective. (See"Control of secondhand smoke exposure"and'Pulmonary function'above.)
●Anticipatory guidance to ensure that adolescents do not begin to smoke or vape, and support for cessation in those who do smoke or vape. (See'Asthma-like symptoms'above.)
In addition, all caregivers of infants with BPD should be taught cardiopulmonary resuscitation (CPR) before discharged from the hospital. We also suggest a "car seat challenge" (cardiorespiratory monitoring of an infant while in a car seat) prior to hospital discharge for all infants with BPD because BPD is a significant risk factor for apnea, bradycardia, and/or oxygen desaturation while in a car seat [187].
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - MANAGEMENT AFTER NEONATAL INTENSIVE CARE UNIT DISCHARGE - Management of specific issues
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Specific needs that are relevant to subgroups of infants are discussed below: Specific needs that are relevant to subgroups of infants are discussed below:
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - MANAGEMENT AFTER NEONATAL INTENSIVE CARE UNIT DISCHARGE - Management of specific issues - -Oxygen therapy
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Hypoxic episodes in infants and children can be linked to and worsen already impaired lung mechanics, elevated airway resistance, and obstruction [ Hypoxic episodes in infants and children can be linked to and worsen already impaired lung mechanics, elevated airway resistance, and obstruction [ 155,161,162 ]. Oxygen supplementation is known to benefit these infants by decreasing airway resistance [ 188 ] and decreasing pulmonary vascular resistance, thus reversing some components of pulmonary artery hypertension [ 189-191 ]. It can also improve central respiratory drive [ 157 ], increase sleep duration by increasing rapid eye movement (REM) sleep [ 159 ], and increase growth velocity [ 169,191,192 ].
Infants beyond term and with mature retinal development should receive oxygen supplementation as needed to maintain a target saturation of 92 percent and a target of approximately 92 to 95 percent in those with pulmonary hypertension (PH) [2,108,193]. After hospital discharge, it is reasonable to use supplemental oxygen as needed to maintain an oxygen saturation target of 90 percent, as suggested in a guideline from the European Respiratory Society (low-certainty evidence) [2]. Altitude may be a risk factor for the development of BPD and dependency on supplemental oxygen [194]; infants living at higher altitudes may be more likely to require supplemental oxygen at hospital discharge [195]. As the infant's respiratory status improves, the supplemental oxygen should be slowly weaned. Adjustments should be guided by monitoring with pulse oximetry in a variety of states, recognizing that oxygenation often decreases during or after feeding [155,196], during sleep [155,157,158], and during intercurrent illnesses. Additionally, sustained growth and stamina for therapies or periods of play must be assured while supplemental oxygen is withdrawn. (See'Sleep hypoxemia'above and"Bronchopulmonary dysplasia (BPD): Management and outcome", section on 'Supplemental oxygen'.)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - MANAGEMENT AFTER NEONATAL INTENSIVE CARE UNIT DISCHARGE - Management of specific issues - -Tracheostomy
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●Management in the home setting– Infants with obstructive central and upper airway disease or who require long-term chronic ventilation may require a tracheostomy for months or even years after hospital discharge [197]. Such infants require coordinated care involving their primary clinician, pediatric otolaryngologist, pulmonologist, and provider of home care services. A speech pathologist is often helpful in the evaluation and management of swallowing and speech development. (See'Central airway disease'above.)
Prior to transition to home care, the family/caregivers must be trained in tracheostomy maintenance and emergency procedures. Two caregivers should be identified and trained in routine suctioning, cleaning and changing the tracheostomy, general respiratory assessment, and CPR of a patient with a tracheostomy including use of a ventilation bag. The caregivers must demonstrate proficiency in routine and emergency skills before the child is discharged from the health care facility to home. They should have a backup tracheostomy tube that is one size smaller (0.5 mm diameter smaller) than the one in use; this will be easier to insert in case of accidental decannulation.
For any child with a tracheostomy who is at high risk for airway complications and cannot call for help or self-correct a problem, some form of monitoring should be used when not under direct visual monitoring. Pulse oximetry is recommended over a cardiorespiratory monitor since hypoxemia will usually occur before bradycardia and a child with a critically obstructed or displaced tracheostomy tube will make ineffective breathing efforts that could delay the cardiorespiratory monitor from alarming. (See'Cardiorespiratory monitoring'below.)
Because all cardiorespiratory monitors have limitations, an awake caregiver including daily support from a skilled nurse care is considered to be a standard of care in the United States for a child living at home with a tracheostomy [198]. Minimum hours of nursing care are eight hours/day for young children with tracheostomies, with additional hours for working parents. This support allows the child to be visually monitored at least while the parent/caregiver(s) sleep. (See'Cardiorespiratory monitoring'below.)
Guidelines on the care of the child with chronic tracheostomy have been published [199]. Children with tracheostomies should undergo periodic bronchoscopy every 6 to 12 months to monitor the airway, assess tracheostomy tube size, and evaluate readiness for decannulation. Granulomas often form near the tracheostomy site and require removal; other complications include recurrent tracheitis or bronchitis, and (rarely) hemorrhage.
●Decannulation– Patient requirements for consideration of decannulation of the tracheostomy tube includeallof the following [200]:
•Successful weaning off of mechanical ventilation
•Stable respiratory status
•Low likelihood for needing mechanical ventilation during acute illnesses
•Adequate level of consciousness
•Effective cough
•Adequate ability to clear secretions
•Cuffless tracheostomy tube in place prior to decannulation
The timing for decannulation for those with a history of subglottic stenosis or other airway abnormalities should be determined by a pediatric otolaryngologist and may be based on airway patency and function, with or without surgical correction.
Direct laryngoscopy and bronchoscopy should be considered in all children prior to decannulation to identify granulomas, suprastomal collapse, and other airway issues that may preclude a successful decannulation [201].
There are no specific protocols for decannulation of children with BPD and the approach to decannulation varies [201-204]. When possible, elective decannulation should occur during the spring and summer months when respiratory viruses are less frequent in the community. Prior to decannulation, the tracheostomy tube is often downsized. The smaller tracheostomy tube should be large enough to avoid mucous plugging and unplanned decannulation. Successful downsizing of a tracheostomy tube and tolerance of a speaking valve are favorable predictors of subsequent successful decannulation.
The trial of decannulation of pediatric patients should occur in the hospital setting. Prior to decannulation, the tracheostomy tube is capped for a period of up to 24 hours while the child is closely monitored to determine readiness for decannulation. Patients who have respiratory symptoms (ie, stridor, tachypnea, increased work of breathing, hypoventilation, apnea, or desaturation) during capping trials are unlikely to be successfully decannulated [205]. Polysomnography can also be used to guide successful timing for decannulation when available [201,202]. One study reported that children with higher apnea/hypopnea indexes during a capped study were less likely to undergo successful decannulation than children with lower apnea/hypopnea indexes [206]. In addition, patients with high apnea/hypopnea indexes can sometimes benefit from an adenoid/tonsillectomy if indicated to minimize obstructive symptoms post-decannulation. Children who fail capping trials should undergo direct laryngoscopy and bronchoscopy to rule out obstructive lesions that can be addressed surgically.
In a retrospective review of 46 pediatric patients undergoing elective decannulation in the inpatient setting, the overall failure rate was 9 percent. Children who failed decannulation tended to be younger and to have vocal cord paralysis, although these findings were not statistically significant. Children who remained asymptomatic for a 24-hour observation period after decannulation were likely to remain successfully decannulated [205].
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - MANAGEMENT AFTER NEONATAL INTENSIVE CARE UNIT DISCHARGE - Management of specific issues - -Home ventilators
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Children with BPD on home ventilation have substantial mortality risks at home, as high as 18.6 percent in one single-center study [ Children with BPD on home ventilation have substantial mortality risks at home, as high as 18.6 percent in one single-center study [ 207 ]. In another study of 102 children with respiratory failure secondary to severe BPD requiring positive pressure ventilation (PPV) at home, 80 percent survived and the majority were weaned off of PPV and decannulated by six years of age, with a median age of liberation from PPV of 24 months [ 207 ]. In another retrospective study of 165 infants requiring tracheostomy and prolonged ventilator support, 58 percent had birth weights <1000 g [ 208 ]. Among the infants with birth weights <1000 g, 95 percent had BPD and 22 percent had pulmonary artery hypertension; five-year survival rate was 94 percent, and the median time to tracheostomy closure was 1.3 years.
In an attempt to guide care and reduce mortality and morbidity, guidelines have been published for the use of chronic invasive ventilation in pediatric patients, including those with BPD [198]. Children on home ventilators should have a medical home with both a generalist and a respiratory subspecialist co-managing care, an alert and attentive caregiver at all times, and at least two trained household members who also receive ongoing education. The guidelines also discuss the use of standardized discharge criteria, pulse-oximetry for monitoring, and specific pieces of essential equipment.
There are no specific guidelines for candidacy for ventilator weaning or standardized protocols for ventilator weaning. Core principles for ventilator weaning include close monitoring in an inpatient setting, but in select patients, outpatient weaning may be done with frequent clinic visits and the use of overnight polysomnography [209]. Effective management of comorbidities such as PH is essential if weaning is to be successful.
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - MANAGEMENT AFTER NEONATAL INTENSIVE CARE UNIT DISCHARGE - Management of specific issues - -Cardiorespiratory monitoring
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Routine use of cardiorespiratory monitors is generally not indicated for children with BPD after hospital discharge. However, cardiorespiratory monitors may be appropriate for the following groups of infants: Routine use of cardiorespiratory monitors is generally not indicated for children with BPD after hospital discharge. However, cardiorespiratory monitors may be appropriate for the following groups of infants:
●Preterm infants with a history of persistent apneas and bradycardias (see"Management of apnea of prematurity")
●Infants who require home supplemental oxygen
●Infants with tracheostomies, with or without supplemental oxygen
For the latter two groups, we suggest use of a pulse oximeter rather than a cardiorespiratory monitor. This is because a cardiorespiratory monitor will only detect changes in heart rate (bradycardia and tachycardia) and central apneas but not obstructive apneas. Pulse oximetry provides earlier warning of an obstructive event or loss of supplemental oxygen because it measures changes in oxygen saturation. (See"Use of home cardiorespiratory monitors in infants".)
Cardiorespiratory monitors have limitations that should be considered and discussed with the caregivers prior to implementation: Cardiorespiratory monitors will only provide indirect evidence of airway compromise and alarms are often delayed. In addition, cardiorespiratory monitoring and pulse oximetry can result in many false alarms, which may lead to caregiver desensitization to alarms. For infants with tracheostomies, cardiorespiratory monitoring and pulse oximetry does not substitute for an "awake" caregiver who is trained in tracheostomy management and resuscitation because preventable tracheostomy events are a significant source of mortality in pediatric patients who are on mechanical ventilators at home [210]. (See'Tracheostomy'above.)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - MANAGEMENT AFTER NEONATAL INTENSIVE CARE UNIT DISCHARGE - Management of specific issues - -Pulmonary hypertension
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Infants who continue to have a need for supplemental oxygen should be screened for PH before hospital discharge, as described in a separate topic review. Infants diagnosed with PH require close follow-up with a PH specialist. Follow-up is particularly important during the first few months after discharge and during respiratory viral season. (See Infants who continue to have a need for supplemental oxygen should be screened for PH before hospital discharge, as described in a separate topic review. Infants diagnosed with PH require close follow-up with a PH specialist. Follow-up is particularly important during the first few months after discharge and during respiratory viral season. (See "Pulmonary hypertension associated with bronchopulmonary dysplasia" and "Pulmonary hypertension associated with bronchopulmonary dysplasia", section on 'Management after hospital discharge' .)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - MANAGEMENT AFTER NEONATAL INTENSIVE CARE UNIT DISCHARGE - Management of specific issues - -Asthma and asthma-like symptoms
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Wheezing and airway hyperresponsiveness are common among children and adolescents with a history of BPD, as noted above (see Wheezing and airway hyperresponsiveness are common among children and adolescents with a history of BPD, as noted above (see 'Asthma-like symptoms' above). Steps to minimize risk include avoidance of tobacco smoke exposure and other inhaled irritants, avoidance of relevant environmental allergens, adherence to routine immunization schedule including annual influenza vaccine, and prompt detection and treatment of respiratory infections. (See "Care of the neonatal intensive care unit graduate", section on 'Immunizations' .)
For children with a history of moderate or severe BPD, it is helpful to perform a baseline assessment using spirometry and to repeat this measure annually and if symptoms develop. For those who develop asthma-like symptoms, spirometric measures can be used to determine responsiveness to bronchodilators. If the symptoms and spirometric measures are consistent with reactive airways disease, it is appropriate to use standard management techniques for asthma. However, children with BPD are less likely to respond to bronchodilators or steroids than children with asthma. (See'Asthma-like symptoms'above and"An overview of asthma management in children and adults".)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - MANAGEMENT AFTER NEONATAL INTENSIVE CARE UNIT DISCHARGE - Management of specific issues - -Obstructive sleep apnea
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Children and young adults with a history of prematurity are at increased risk for obstructive sleep apnea and should be evaluated if they have suggestive signs or symptoms, such as apneic pauses with sleep, loud snoring, restless sleep, daytime irritability, morning headaches, etc. Polysomnography is also indicated for infants or children with BPD and symptoms of upper airway obstruction during sleep as primary snoring may be difficult to distinguish from obstructive sleep apnea by history alone [ Children and young adults with a history of prematurity are at increased risk for obstructive sleep apnea and should be evaluated if they have suggestive signs or symptoms, such as apneic pauses with sleep, loud snoring, restless sleep, daytime irritability, morning headaches, etc. Polysomnography is also indicated for infants or children with BPD and symptoms of upper airway obstruction during sleep as primary snoring may be difficult to distinguish from obstructive sleep apnea by history alone [ 211 ]. (See "Evaluation of suspected obstructive sleep apnea in children" .)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - SOCIETY GUIDELINE LINKS
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Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See"Society guideline links: Pulmonary hypertension in children"and"Society guideline links: Bronchopulmonary dysplasia".)
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complications-and-long-term-pulmonary-outcomes-of-bronchopulmonary-dysplasia - SUMMARY AND RECOMMENDATIONS
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●Overview– Early lung injury in infancy due to bronchopulmonary dysplasia (BPD) can have lifelong consequences, manifested by altered pulmonary function, upper and lower airway disease, and pulmonary hypertension (PH). Infants with extremely low birth weight (ELBW; birth weight <1000 g) are especially vulnerable. (See'Respiratory disorders associated with bronchopulmonary dysplasia'above.)
●Pathogenesis of BPD– In the modern era, the most important feature of BPD is impaired alveolar development, with decreased septation and alveolar hypoplasia leading to fewer and larger alveoli and dysmorphic pulmonary vasculature. The lungs often undergo "catch-up" alveolar growth throughout infancy and childhood, so that many affected individuals develop nearly normal lung function and pulmonary reserve with time.
In infants who were born before the advent of modern neonatal intensive care unit management techniques, BPD is typically characterized by airway injury with inflammation and alveolar septal fibrosis, known as "classic" BPD. These changes are usually associated with oxygen toxicity, barotrauma/volutrauma, and infection. (See'New versus classic bronchopulmonary dysplasia'above.)
●Issues arising during long-term management
•General care– To optimize lung function, it is important to minimize lung injury by avoiding recurrent respiratory infections, minimize feeding-related aspiration, and optimize nutrition, particularly during the first two years of life. (See'General measures'above.)
•Asthma-like symptoms– Recurrent wheezing episodes are common in children and adolescents with a history of BPD, but the underlying pathophysiology differs from asthma. If spirometry suggests obstructive lung disease, a trial of standard asthma management techniques is appropriate. Bronchodilators are effective in approximately one-half of these patients. Similarly, children with BPD may respond to inhaled corticosteroids, but the effect is less consistent than in children with asthma. In general, the use of bronchodilators and inhaled corticosteroids should be limited to specific subgroups of patients with BPD, based on European and American guidelines. (See'Asthma and asthma-like symptoms'above.)
•Associated PH– All infants with moderate or severe BPD should be screened for PH using echocardiography. For most infants, the initial echocardiogram should be performed at the time the formal diagnosis of BPD is made. Earlier screening should be performed for selected infants with severe respiratory symptoms or risk factors, or if an anesthetic procedure is planned, because PH is associated with increased risk of complications during anesthesia. (See"Pulmonary hypertension associated with bronchopulmonary dysplasia", section on 'Screening'.)
•Central airway disease– Infants with BPD, and especially those with "classic" BPD, are at risk for central airway collapse due to tracheobronchomalacia, which can exacerbate underlying thoracic airway disease. Clinical manifestations include "BPD spells" (cyanotic or life-threatening episodes), chronic wheezing unresponsive to bronchodilator therapy, propensity for atelectasis, and long-term dependence on mechanical ventilation and/or tracheostomy. (See'Central airway disease'above.)
ACKNOWLEDGMENT— The UpToDate editorial staff acknowledges Leslie L Harris, MD, and James M Adams, Jr, MD, who contributed to an earlier version of this topic review.
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - SUMMARY AND RECOMMENDATIONS
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●Pathophysiology– CDH is a developmental defect in the diaphragm that allows abdominal viscera to herniate into the chest, thereby compressing the lung and interfering with normal fetal lung development. With increased compression of the developing lung by the herniated abdominal contents, there are corresponding decreases in bronchial and pulmonary arterial branching, resulting in increasing degrees of lung hypoplasia and pulmonary arterial muscle hyperplasia (pulmonary hypertension). (See'Pathogenesis and embryology'above and'Impact on cardiopulmonary development'above.)
●Epidemiology– Reported prevalence rates of CDH range from 2 to 3 cases per 10,000 live births. It is slightly more common in males than females. (See'Prevalence'above.)
●Presentation– In many cases, the diagnosis of CDH is known at the time of birth based upon the prenatal ultrasound. Patients not diagnosed prenatally generally present with respiratory distress in the first few hours or days after birth. Physical examination may reveal a barrel-shaped chest, a scaphoid-appearing abdomen because of loss of the abdominal contents into the chest, and the absence of breath sounds on the ipsilateral side. (See'Postnatal findings'above.)
Less commonly, a small subset of patients with CDH have minimal or no symptoms in the newborn period and present later in life. (See'Late presentation'above.)
●Associated conditions– Associated congenital abnormalities are seen in approximately 50 percent of newborns with CDH. The most common associated condition is congenital heart disease, which occurs in 15 to 20 percent of cases and can be severe. A wide range of noncardiac abnormalities can also be seen. Approximately 5 to 10 percent of newborns with CDH have an identified underlying genetic syndrome or chromosomal abnormality. (See'Associated conditions'above.)
●Diagnosis– The diagnosis is often made prenatally with ultrasound examination. Among infants in whom CDH is not diagnosed in utero, the diagnosis is made by chest radiography showing herniation of abdominal contents (image 1). (See"Congenital diaphragmatic hernia: Prenatal issues", section on 'Prenatal diagnosis'.)
All neonates with CDH should undergo echocardiography early in the postnatal course to detect any associated cardiac anomalies, evaluate ventricular function, and to assess for pulmonary hypertension (PH) (image 2A-B). (See'Echocardiography'above.)
●Differential diagnosis– The differential diagnosis of neonatal CDH includes other causes of neonatal respiratory distress, including infections (sepsis, pneumonia) and noninfectious etiologies (table 1). CDH is differentiated from these conditions by the characteristic chest radiograph finding of herniated abdominal contents into the thorax (image 1). (See"Overview of neonatal respiratory distress and disorders of transition".)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - INTRODUCTION
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Congenital diaphragmatic hernia (CDH) is a developmental defect of the diaphragm that allows abdominal viscera to herniate into the chest. Affected neonates usually present in the first few minutes to hours after birth with respiratory distress that can range from mild to life-threatening. With improvements in antenatal diagnosis and neonatal care, survival has improved. However, infants with CDH continue to have a considerable risk of mortality and morbidity.
The clinical manifestations and diagnosis of CDH in the newborn will be reviewed here. Related topics include:
●Pathogenesis, anatomy, prenatal detection, and prenatal management of CDH. (See"Congenital diaphragmatic hernia: Prenatal issues".)
●Postnatal management and outcome of CDH in the newborn. (See"Congenital diaphragmatic hernia (CDH) in the neonate: Management and outcome".)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - PREVALENCE
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Reported prevalence rates of CDH range from 2 to 3 cases per 10,000 live births [1,2]. It is more common in males than females, with a male-to-female ratio of 1.4 to 1 [2]. Approximately 5 to 10 percent of cases are associated with a chromosomal abnormality or genetic syndrome [2]. (See'Associated conditions'below.)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - PATHOGENESIS AND EMBRYOLOGY
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CDH results from failure of normal closure of the pleuroperitoneal folds during the fourth to tenth weeks postfertilization, which allows herniation of viscera into the thoracic cavity. This interferes with normal lung development and has other adverse consequences. The reason for failure of normal diaphragmatic closure is not fully understood. The embryology, pathogenesis, and anatomy of CDH are discussed in greater detail separately. (See"Congenital diaphragmatic hernia: Prenatal issues", section on 'Pathogenesis'and"Congenital diaphragmatic hernia: Prenatal issues", section on 'Anatomic findings'.)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - IMPACT ON CARDIOPULMONARY DEVELOPMENT
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Because herniation occurs during a critical period of lung development, clinical manifestations of CDH result from the pathologic effects of the herniated viscera on lung development. With rising severity of lung compression, there are corresponding decreases in bronchial and pulmonary arterial branching, resulting in increasing degrees of pulmonary hypoplasia. Pulmonary hypoplasia is most severe on the ipsilateral side. However, pulmonary hypoplasia may develop on the contralateral side if the mediastinum shifts and compresses the lung. Arterial branching is reduced, resulting in muscular hyperplasia of the pulmonary arterial tree, which contributes to the increased risk of pulmonary hypertension (PH) [3].
In addition, hypoplasia of the left ventricle and other left heart structures (aortic valve, transverse aortic arch, aortic isthmus) contribute to adverse outcomes in CDH [4-7]. (See"Hypoplastic left heart syndrome: Anatomy, clinical features, and diagnosis".)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - CLINICAL MANIFESTATIONS - Prenatal presentation
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Many patients with CDH are identified through routine prenatal ultrasound. Prenatal ultrasound can also identify other associated anomalies (eg, cardiac abnormalities). Prenatal presentation and diagnosis are discussed in greater detail separately. (See Many patients with CDH are identified through routine prenatal ultrasound. Prenatal ultrasound can also identify other associated anomalies (eg, cardiac abnormalities). Prenatal presentation and diagnosis are discussed in greater detail separately. (See "Congenital diaphragmatic hernia: Prenatal issues", section on 'Prenatal diagnosis' .)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - CLINICAL MANIFESTATIONS - Postnatal findings - -Presentation
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Postnatally, infants with CDH most often present with respiratory distress in the first few minutes after birth. Less commonly, a small subset of patients with CDH have minimal or no symptoms in the newborn period and present later in life. (See Postnatally, infants with CDH most often present with respiratory distress in the first few minutes after birth. Less commonly, a small subset of patients with CDH have minimal or no symptoms in the newborn period and present later in life. (See 'Late presentation' below.)
In patients who present as neonates, the degree of respiratory distress depends upon the severity of lung hypoplasia and the development of pulmonary hypertension (PH). Following delivery, hypoxemia, hypercarbia, and acidosis increase the risk of PH by inducing a reactive vasoconstrictive element to the preexisting fixed arterial muscular hyperplasia component. In some cases, pulmonary hypoplasia is so severe as to be incompatible with life. (See"Persistent pulmonary hypertension of the newborn (PPHN): Clinical features and diagnosis", section on 'Pathogenesis'and"Congenital diaphragmatic hernia (CDH) in the neonate: Management and outcome", section on 'Survival'.)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - CLINICAL MANIFESTATIONS - Postnatal findings - -Physical findings
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Physical findings in the newborn include a barrel-shaped chest, a scaphoid-appearing abdomen (because of loss of the abdominal contents into the chest), and absence of breath sounds on the ipsilateral side. In patients with a left-sided CDH, the heartbeat is displaced to the right because of a shift in the mediastinum. Physical findings in the newborn include a barrel-shaped chest, a scaphoid-appearing abdomen (because of loss of the abdominal contents into the chest), and absence of breath sounds on the ipsilateral side. In patients with a left-sided CDH, the heartbeat is displaced to the right because of a shift in the mediastinum.
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - CLINICAL MANIFESTATIONS - Postnatal findings - -Laterality
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In most cases of CDH, herniation occurs on the left. Right-sided CDH occurs in approximately 15 percent of cases and bilateral herniation in 1 to 2 percent [ In most cases of CDH, herniation occurs on the left. Right-sided CDH occurs in approximately 15 percent of cases and bilateral herniation in 1 to 2 percent [ 8-10 ]. There may be a higher incidence of pulmonary complications associated with right- versus left-sided CDH [ 9 ]. Bilateral herniation is associated with a high mortality rate [ 10 ]. (See "Congenital diaphragmatic hernia (CDH) in the neonate: Management and outcome", section on 'Outcome' .)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - CLINICAL MANIFESTATIONS - Associated conditions
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Associated congenital abnormalities are seen in approximately 50 percent of newborns with CDH. In some cases, the associated abnormalities are identified prenatally. However, in many cases, the full extent of associated abnormalities is not appreciated until after delivery. (See Associated congenital abnormalities are seen in approximately 50 percent of newborns with CDH. In some cases, the associated abnormalities are identified prenatally. However, in many cases, the full extent of associated abnormalities is not appreciated until after delivery. (See "Congenital diaphragmatic hernia: Prenatal issues", section on 'Associated fetal abnormalities' .)
●Congenital heart disease– Congenital heart disease is the most common type of associated congenital abnormality in infants with CDH [11-13]. In a meta-analysis of 51 observational studies including >15,000 newborns with CDH, 17 percent of patients had associated congenital heart disease [12]. The most common defects were:
•Ventricular septal defects (accounting for 24 percent of all congenital heart defects in these reports) (see"Isolated ventricular septal defects (VSDs) in infants and children: Anatomy, clinical features, and diagnosis")
•Atrial septal defects (21 percent) (see"Isolated atrial septal defects (ASDs) in children: Classification, clinical features, and diagnosis")
•Single-ventricle defects, including hypoplastic left heart syndrome (12 percent) (see"Hypoplastic left heart syndrome: Anatomy, clinical features, and diagnosis")
•Coarctation of the aorta (9 percent) (see"Clinical manifestations and diagnosis of coarctation of the aorta")
•Tetralogy of Fallot (5 percent) (see"Tetralogy of Fallot (TOF): Pathophysiology, clinical features, and diagnosis")
Because of the strong association between CDH and congenital heart disease, all newborns with CDH should undergo postnatal echocardiography. (See'Echocardiography'below.)
●Noncardiac abnormalities– A wide range of noncardiac abnormalities can be seen in newborns with CDH, including [14]:
•Neural tube defects (see"Neural tube defects: Overview of prenatal screening, evaluation, and pregnancy management")
•Central nervous system malformations (eg, agenesis of the corpus callosum, hydrocephalus)
•Genitourinary defects (eg, hydronephrosis, megaureter, hypospadias, solitary kidney, cystic kidneys) (see"Overview of congenital anomalies of the kidney and urinary tract (CAKUT)")
•Esophageal atresia (see"Congenital anomalies of the intrathoracic airways and tracheoesophageal fistula", section on 'Tracheoesophageal fistula and esophageal atresia')
•Polysplenia
•Cryptorchidism (see"Undescended testes (cryptorchidism) in children: Clinical features and evaluation")
•Skeletal abnormalities (eg, supernumerary ribs, limb abnormalities, hemivertebrae)
●Genetic syndromes– Approximately 5 to 10 percent of newborns with CDH have an identified underlying genetic syndrome or chromosomal abnormality [2,15-17]. An underlying genetic syndrome is more likely if there are other associated malformations (eg, congenital heart disease) and/or the newborn has bilateral CDH. Examples include:
•Fryns syndrome, which is characterized by CDH, pulmonary hypoplasia, craniofacial abnormalities, and distal limb deformities. It is usually lethal in the neonatal period.
•Donnai-Barrow syndrome(LRP2 mutation), which is characterized by CDH, facial dysmorphisms (prominent brow, short nose, hypertelorism), ocular abnormalities, and sensorineural hearing loss.
•Others – Numerous other genetic syndromes are occasionally associated with CDH. Examples include theCHARGE association,Apert syndrome,Coffin-Siris syndrome,Emanuel syndrome,Cornelia De Lange syndrome,Goldenhar syndrome(also called hemifacial microsomia),Beckwith-Wiedemann syndrome,Pallister Killian syndrome,Stickler syndrome,Wolf-Hirschhorn syndrome, and others [15-17].
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - DIAGNOSIS - Prenatal
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Many cases of CDH are diagnosed prenatally by routine antenatal ultrasound screening. This is discussed separately. (See Many cases of CDH are diagnosed prenatally by routine antenatal ultrasound screening. This is discussed separately. (See "Congenital diaphragmatic hernia: Prenatal issues", section on 'Prenatal diagnosis' and 'Chest imaging' below.)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - DIAGNOSIS - Postnatal
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While most infants with CDH are diagnosed prenatally, a small subset present postnatally with respiratory distress. In these newborns, stabilization efforts in the delivery room take precedence over diagnostic testing. Once the newborn is stabilized, chest imaging and echocardiography are performed. While most infants with CDH are diagnosed prenatally, a small subset present postnatally with respiratory distress. In these newborns, stabilization efforts in the delivery room take precedence over diagnostic testing. Once the newborn is stabilized, chest imaging and echocardiography are performed.
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - DIAGNOSIS - Postnatal - -Initial stabilization
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Postnatally, newborns with CDH often present with severe respiratory distress within the first few minutes after birth. Stabilization in the delivery room includes intubation, placement of a nasogastric tube, and other measures to support the newborn’s respiratory and hemodynamic status. These interventions are discussed in greater detail separately. (See Postnatally, newborns with CDH often present with severe respiratory distress within the first few minutes after birth. Stabilization in the delivery room includes intubation, placement of a nasogastric tube, and other measures to support the newborn’s respiratory and hemodynamic status. These interventions are discussed in greater detail separately. (See "Congenital diaphragmatic hernia (CDH) in the neonate: Management and outcome", section on 'Initial interventions' and "Neonatal resuscitation in the delivery room" .)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - DIAGNOSIS - Postnatal - -Chest imaging
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Chest radiograph findings include: Chest radiograph findings include:
●Herniation of abdominal contents (usually air- or fluid-containing bowel) into the hemithorax with little or no visible aerated lung on the affected side (image 1)
●Displacement of mediastinal structures (eg, heart) towards the contralateral lung
●Compression of the contralateral lung
●Reduced size of the abdomen with decreased or absent air-containing intra-abdominal bowel
●If the CDH is right sided, the liver may be the only herniated organ, appearing as a large thoracic soft tissue mass with absent intra-abdominal liver shadow
The diagnosis may be facilitated by placing a naso- or orogastric tube. Chest radiography will show deviation from the tube's expected anatomic course, typically showing the tube within the thoracic cavity [18].
Cross sectional imaging (eg, with computed tomography [CT]) is only necessary in rare cases when the diagnosis is uncertain.
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - DIAGNOSIS - Postnatal - -Echocardiography
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All neonates with CDH should undergo echocardiography early in the postnatal course to detect any associated cardiac anomalies, evaluate ventricular function, assess the size of the patent ductus arteriosus, assess the degree and direction of ductal and intracardiac shunting, and to assess for pulmonary hypertension (PH) ( All neonates with CDH should undergo echocardiography early in the postnatal course to detect any associated cardiac anomalies, evaluate ventricular function, assess the size of the patent ductus arteriosus, assess the degree and direction of ductal and intracardiac shunting, and to assess for pulmonary hypertension (PH) ( image 2A-B ).
●Congenital heart disease– Approximately 15 to 20 percent of patients with CDH have associated congenital heart defects [12]. (See'Associated conditions'above.)
Infants with associated severe cardiac anomalies are at considerably higher risk for morbidity and mortality, and these findings may have an impact on management decisions [11,19-21]. The prognosis is particularly poor for infants with comorbid hypoplastic left heart syndrome (HLHS). (See"Hypoplastic left heart syndrome: Management and outcome", section on 'Outcome'.)
●PH and ventricular function– In addition to evaluating cardiac anatomy, the echocardiogram assesses ventricular function and estimates the right ventricular pressure to establish if there is evidence of PH (image 2B). The echocardiographic assessment for determining the presence and severity of PH in neonates is discussed separately. (See"Persistent pulmonary hypertension of the newborn (PPHN): Clinical features and diagnosis", section on 'Severity of PH'.)
Neonates with severe biventricular dysfunction often require extracorporeal membrane oxygenation (ECMO) support and have a high risk of morbidity and mortality [22,23]. (See"Congenital diaphragmatic hernia (CDH) in the neonate: Management and outcome", section on 'Extracorporeal membrane oxygenation'.)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - LATE PRESENTATION
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Infrequently, mild CDH defects present after the neonatal period. In a case series of 15 children who presented late with CDH, the mean age at presentation was 18 months (range 38 days to 10 years) [24]. The main presenting symptoms were respiratory complaints in 40 percent of patients, gastrointestinal (GI) symptoms in 40 percent, and both respiratory and GI symptoms in 20 percent. One-third of the patients had failure to thrive. The diagnosis was made by chest radiography in six patients, and the other patients were diagnosed by gastrointestinal contrast series or computed tomography (CT). Primary repair was successful in all patients, and all patients were alive and clinically well at an average follow-up of two years.
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - DIFFERENTIAL DIAGNOSIS
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The differential diagnosis of neonatal CDH includes other causes of neonatal respiratory distress, including infections (sepsis, pneumonia) and noninfectious etiologies (table 1). CDH is differentiated from these conditions by the characteristic chest radiograph finding of herniated abdominal contents into the thorax (image 1). (See"Overview of neonatal respiratory distress and disorders of transition".)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - SOCIETY GUIDELINE LINKS
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Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See"Society guideline links: Pulmonary hypertension in children".)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - INFORMATION FOR PATIENTS
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UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5thto 6thgrade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10thto 12thgrade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see"Patient education: Congenital diaphragmatic hernia (The Basics)")
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-clinical-features-and-diagnosis - SUMMARY AND RECOMMENDATIONS
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●Pathophysiology– CDH is a developmental defect in the diaphragm that allows abdominal viscera to herniate into the chest, thereby compressing the lung and interfering with normal fetal lung development. With increased compression of the developing lung by the herniated abdominal contents, there are corresponding decreases in bronchial and pulmonary arterial branching, resulting in increasing degrees of lung hypoplasia and pulmonary arterial muscle hyperplasia (pulmonary hypertension). (See'Pathogenesis and embryology'above and'Impact on cardiopulmonary development'above.)
●Epidemiology– Reported prevalence rates of CDH range from 2 to 3 cases per 10,000 live births. It is slightly more common in males than females. (See'Prevalence'above.)
●Presentation– In many cases, the diagnosis of CDH is known at the time of birth based upon the prenatal ultrasound. Patients not diagnosed prenatally generally present with respiratory distress in the first few hours or days after birth. Physical examination may reveal a barrel-shaped chest, a scaphoid-appearing abdomen because of loss of the abdominal contents into the chest, and the absence of breath sounds on the ipsilateral side. (See'Postnatal findings'above.)
Less commonly, a small subset of patients with CDH have minimal or no symptoms in the newborn period and present later in life. (See'Late presentation'above.)
●Associated conditions– Associated congenital abnormalities are seen in approximately 50 percent of newborns with CDH. The most common associated condition is congenital heart disease, which occurs in 15 to 20 percent of cases and can be severe. A wide range of noncardiac abnormalities can also be seen. Approximately 5 to 10 percent of newborns with CDH have an identified underlying genetic syndrome or chromosomal abnormality. (See'Associated conditions'above.)
●Diagnosis– The diagnosis is often made prenatally with ultrasound examination. Among infants in whom CDH is not diagnosed in utero, the diagnosis is made by chest radiography showing herniation of abdominal contents (image 1). (See"Congenital diaphragmatic hernia: Prenatal issues", section on 'Prenatal diagnosis'.)
All neonates with CDH should undergo echocardiography early in the postnatal course to detect any associated cardiac anomalies, evaluate ventricular function, and to assess for pulmonary hypertension (PH) (image 2A-B). (See'Echocardiography'above.)
●Differential diagnosis– The differential diagnosis of neonatal CDH includes other causes of neonatal respiratory distress, including infections (sepsis, pneumonia) and noninfectious etiologies (table 1). CDH is differentiated from these conditions by the characteristic chest radiograph finding of herniated abdominal contents into the thorax (image 1). (See"Overview of neonatal respiratory distress and disorders of transition".)
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congenital-diaphragmatic-hernia-cdh-in-the-neonate-management-and-outcome - SUMMARY AND RECOMMENDATIONS
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●Initial medical management– Initial management of the neonate with congenital diaphragmatic hernia (CDH) includes the following measures (see'Initial interventions'above):
•Intubation– All newborns with CDH are immediately intubated in the delivery room (or upon diagnosis if the neonate is diagnosed postnatally) to prevent further dilation of abdominal contents. Oral/nasal bag-mask ventilation should beavoidedsince this leads to gastric distension and further compression of the lung. (See'Initial interventions'above.)
•Mechanical ventilation– The mechanical ventilation strategy should avoid high pressures to minimize lung injury. For most neonates, we suggest conventional mechanical ventilation (CMV) with pressure-limited breaths initially rather than other modalities (Grade 2C). High frequency ventilation (HFV) may be preferred for patients with more severe defects; HFV is also used for patients who fail CMV. (See'Mechanical ventilation'above.)
•Gastric decompression– A nasogastric tube is placed in the delivery room and connected to continuous suction for decompression of the stomach and intestines. (See'Initial interventions'above.)
•Hemodynamic support– Hemodynamic support includes isotonic fluids and inotropic agents (eg,dopamine). The goal is to maintain blood pressure (BP) at the upper limits of normal (ie, mean BP 45 to 55 mmHg) to minimize right-to-left shunting. In some cases,hydrocortisonemay be used for neonates with refractory shock. These interventions are discussed separately. (See"Neonatal shock: Management"and"Persistent pulmonary hypertension of the newborn (PPHN): Management and outcome", section on 'Hemodynamic support'.)
•Pulmonary vasodilator therapy– For patients with pulmonary hypertension (PH) that is associated with significant hypoxemia from right-to-left shunting (ie, preductal SpO2<85 percent or pre- to postductal SpO2differential >10 percent) despite optimizing ventilatory support and sedation, we suggest a trial ofinhaled nitric oxide(iNO) (Grade 2C). (See'Management of pulmonary hypertension'above.)
The approach to using iNO in this setting is similar to the management of neonates with PH due to other causes, as discussed separately. (See"Persistent pulmonary hypertension of the newborn (PPHN): Management and outcome", section on 'Inhaled nitric oxide (iNO)'.)
●Refractory respiratory and/or hemodynamic instability– For infants who have refractory respiratory and/or hemodynamic instability despite optimal medical therapy (including ventilatory support, inotropic support, and iNO), we suggest extracorporeal membrane oxygenation (ECMO) (Grade 2C). Specific eligibility and exclusion criteria for ECMO are provided above. (See'Extracorporeal membrane oxygenation'above.)
●Timing of surgery– The timing of surgical repair is based upon the degree of pulmonary hypoplasia and PH (see'Timing of repair'above):
•Patients without pulmonary hypoplasia or PH– For patients with only mild respiratory impairment requiring minimal support, we suggest early repair (typically within 48 to 72 hours after birth) (Grade 2C). (See'Patients without pulmonary hypoplasia or PH'above.)
•Patients with reversible PH (not requiring ECMO)– For patients with mild to moderate pulmonary hypoplasia and reversible PH who are managed without ECMO, we suggest deferring surgery until PH is resolved rather than early repair (Grade 2C). In most cases, repair can be successfully completed after 5 to 10 days. (See'Patients with reversible PH (not requiring ECMO)'above.)
•Patients who require ECMO– For infants who require ECMO, the optimal timing of operative repair is uncertain. When feasible, we suggest deferring surgery until after the infant's pulmonary status has improved, PH has resolved, and they are off ECMO (Grade 2C). However, repair on ECMO may be necessary if the defect causes significant mediastinal shift resulting in impaired ECMO flow or if the neonate's pulmonary hypoplasia is so severe that weaning ECMO is expected to be impossible without surgical repair. (See'Patients who require ECMO'above.)
●Surgical repair– Surgical repair consists of reduction of the abdominal viscera and closure of the diaphragmatic defect (picture 1). The size of the defect determines the type of repair. Smaller defects may be repaired with sutures alone (primary repair). Large CDHs require patch or muscle flap repair. Potential perioperative complications include PH exacerbations, bleeding, infection, and chylothorax. (See'Type of repair'above and'Perioperative complications'above.)
●Outcome
•Survival– In the contemporary era, survival rates for live-born infants with CDH range from 70 to 92 percent. Risk factors for mortality include prematurity or low birth weight, large size of the defect, associated cardiac defects, severe PH, need for ECMO, birth at a nontertiary center, and poor gas exchange in the early postnatal period. (See'Survival'above.)
•Long-term complications– Long-term complications in survivors of CDH include chronic lung disease, gastroesophageal reflux, growth failure, CDH recurrence, neurodevelopmental impairment, and chest wall deformities (pectus excavatum, pectus carinatum, and scoliosis). (See'Long-term complications'above.)
●Follow-up– Structured follow-up, often involving a multidisciplinary team, facilitates early recognition and treatment of the associated complications. (See'Follow-up'above.)
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