Positive End-Expiratory Pressure During Anesthesia For Prevention Of Postoperative Pulmonary Complications

OBJECTIVE: Whether intraoperative positive end-expiratory pressure(PEEP)can reduce the risk of postoperative pulmonary complications remains controversial.We performed a systematic review of currently available literature to investigate whether intraoperative PEEP decreases pulmonary complications in anesthetized patients undergoing surgery.METHODS: We searched Pub Med,Embase,and the Cochrane Library to identify randomized controlled trials(RCTs)that compared intraoperative PEEP versus zero PEEP(ZEEP)for postoperative pulmonary complications in adults.The prespecifed primary outcome was postoperative pulmonary atelectasis.RESULTS: Fourteen RCTs enrolling 1238 patients met the inclusion criteria.Metaanalysis using a random-effects model showed a decrease in postoperative atelectasis(relative risk [RR],0.51;95% confdence interval [CI],0.35–0.76;trial sequential analyses [TSA]-adjusted CI,0.10–2.55)and postoperative pneumonia(RR,0.48;95% CI,0.27–0.84;TSA-adjusted CI,0.05–4.86)in patients receiving PEEP ventilation.However,TSA showed that the cumulative Z-curve of 2 outcomes crossed the conventional boundary but did not cross the trial sequential monitoring boundary,indicating a possible false-positive result.We observed no effect of PEEP versus ZEEP ventilation on postoperative mortality(RR,1.78;95% CI,0.55–5.70).CONCLUSIONS: The evidence that intraoperative PEEP reduces postoperative pulmonary complications is suggestive but too unreliable to allow defnitive conclusions to be drawn.