text_1: 总体而言 , 抗生素 组 患者 的 呼吸机 相关 性肺炎 风险 低于 安慰剂 组 ( 风险 比 , 0.55 ; 95% CI , 0.33 ~ 0.91 ) ( 图 2B ) .
  
text_2: overall , the risk of ventilator @-@ associated pneumonia was lower among patients who received antibiotics than those who received placebo ( hazard ratio , 0.55 ; 95 % CI , 0.33 to 0.91 ) ( Figure 2B ) .
  