Effects of positive end-expiratory pressure/recruitment manoeuvres compared with zero end-expiratory pressure on atelectasis in children: A randomised clinical trial.

Abstract

BACKGROUNDAtelectasis is a common postoperative complication. Peri-operative lung protection can reduce atelectasis; however, it is not clear whether this persists into the postoperative period.OBJECTIVETo evaluate to what extent lung-protective ventilation reduces peri-operative atelectasis in children undergoing nonabdominal surgery.DESIGNRandomised, controlled, double-blind study.SETTINGSingle tertiary hospital, 25 July 2019 to 18 January 2020.PATIENTSA total of 60 patients aged 1 to 6 years, American Society of Anesthesiologists physical status 1 or 2, planned for nonabdominal surgery under general anaesthesia (≤2 h) with mechanical ventilation.INTERVENTIONSThe patients were assigned randomly into either the lung-protective or zero end-expiratory pressure with no recruitment manoeuvres (control) group. Lung protection entailed 5 cmH2O positive end-expiratory pressure and recruitment manoeuvres every 30 min. Both groups received volume-controlled ventilation with a tidal volume of 6 ml kg−1 body weight. Lung ultrasound was conducted before anaesthesia induction, immediately after induction, surgery and tracheal extubation, and 15 min, 3 h, 12 h and 24 h after extubation.MAIN OUTCOME MEASURESThe difference in lung ultrasound score between groups at each interval. A higher score indicates worse lung aeration.RESULTSPatients in the lung-protective group exhibited lower median [IQR] ultrasound scores compared with the control group immediately after surgery, 4 [4 to 5] vs. 8 [4 to 6], (95% confidence interval for the difference between group values −4 to −4, Z = -6.324) and after extubation 3 [3 to 4] vs. 4 [4 to 4], 95% CI −1 to 0, Z = −3.161. This did not persist from 15 min after extubation onwards. Lung aeration returned to normal in both groups 3 h after extubation.CONCLUSIONSThe reduced atelectasis provided by lung-protective ventilation does not persist from 15 min after extubation onwards. Further studies are needed to determine if it yields better results in other types of surgery.TRIAL REGISTRATIONChictr.org.cn (ChiCTR2000033469).