Ventilation with high versus low peep levels during general anaesthesia for open abdominal surgery does not affect postoperative spirometry: A randomised clinical trial.

Abstract

Invasive mechanical ventilation during general anaesthesia for surgery typically causes atelectasis and impairs postoperative lung function. We investigated the effect of intraoperative ventilation with high positive end-expiratory pressure (PEEP) and recruitment manoeuvres (RMs) on postoperative spirometry. This was a preplanned, single-centre substudy of an international multicentre randomised controlled trial, the PROVHILO trial. University hospital from November 2011 to January 2013. Nonobese patients scheduled for major abdominal surgery at a high risk of postoperative pulmonary complications (PPCs). Intraoperative low tidal volume ventilation with PEEP levels of 12 cmH2O and RM (the high PEEP group) or with PEEP levels of 2 cmH2O or less without RM (the low PEEP group). Time-weighted averages (TWAs) of the forced expiratory volume in 1 s (FEV1) and the forced vital capacity (FVC) up to postoperative day five. Thirty-one patients were allocated to the high PEEP group and 32 to the low PEEP group. No postoperative spirometry test results were available for 6 patients. In both groups, TWA of FEV1 and FVC until postoperative day five were lower than preoperative values. Postoperative spirometry test results were not different between the high and low PEEP group; Data are median [interquartile range], TWA FVC 1.8 [1.6 to 2.4] versus 1.7 [1.2 to 2.4] l (P = NS) and TWA FEV1 1.2 [1.1 to 2.5] versus 1.2 [0.9 to 1.9] l (P = NS). Patients who developed PPCs had lower FEV1 and FVC on postoperative day five; 1.1 [0.9 to 1.6] versus 1.6 [1.4 to 1.9] l (P = 0.001) and 1.6 [1.2 to 2.6] versus 2.3 [1.7 to 2.6] l (P = 0.036), respectively. Postoperative spirometry is not affected by PEEP and RM during intraoperative ventilation for open abdominal surgery in nonobese patients at a high risk of PPCs, but rather is associated with the development of PPCs. ClinicalTrials.gov NCT01441791.