High vs Low PEEP for Postoperative Pulmonary Complications in Obese Individuals

Postoperative pulmonary complications in obese individuals given general anesthesia for surgery did not improve with the use of an intraoperative mechanical ventilation strategy with alveolar recruitment maneuvers and higher levels of positive end-expiratory pressure (PEEP), according to a study recently published in the Journal of American Medical Association.

The Protective Intraoperative Ventilation With Higher vs Lower Levels of Positive End-Expiratory Pressure in Obese Patients (PROBESE; ClinicalTrials.gov Identifier: NCT02148692) conducted between July 2014 and February 2018 included 1976 adult participants undergoing nonneurologic, noncardiac surgery with general anesthesia, all of whom were at significant risk for postoperative pulmonary complications. All had a body mass index of ≥35; participants were randomly assigned to high PEEP (n=989; 12 cm H2O with alveolar recruitment maneuvers) or low PEEP (n=987; 4 cm H2O). Volume-controlled ventilation with a 7 mL/kg of predicted body weight tidal volume was administered to all participants.

The study’s primary outcome was the number of pulmonary complications (including acute respiratory distress syndrome, respiratory failure, new pulmonary infiltrates, aspiration pneumonitis, atelectasis, pneumothorax, bronchospasm, pulmonary infection, pleural effusion, and cardiopulmonary edema) in the first 5 days after surgery. Kaplan-Meier survival curves were used to assess time until postoperative complications.

Pulmonary complications occurred in 21.3% (n=211) of participants in the group with high PEEP vs 23.6% (n=233) in the low-PEEP group (risk ratio, 0.93;95% CI, 0.83-1.04; P =.23). Pleural effusion varied significantly, with 4.3% (n=43) vs 2.1% (n=21) in the high- vs low-PEEP groups (risk ratio, 1.35; 95% CI, 1.14-1.62; P =.005). In addition, significantly fewer participants in the high-PEEP group compared with the low-PEEP group had hypoxemia (5.0% vs 13.6%, respectively; P <.001). However, in terms of the 9 secondary outcomes, 6 were not significantly different between the high- and low-PEEP groups.

Limitations to this study included a lack of blinding among intraoperative anesthesiologists, stepwise increases in tidal volume of the alveolar recruitment maneuver, a lack of individual titration in PEEP level, a lack of standardized respiratory management between sites, differing levels of severity between events, and an inability to distinguish incisions in the upper vs lower abdomen.

The study researchers concluded that in “obese patients undergoing surgery under general anesthesia, an intraoperative mechanical ventilation strategy with a higher level of PEEP and alveolar recruitment maneuvers, compared with a strategy with a lower level of PEEP, did not reduce postoperative pulmonary complications.”

Disclosures: Dr Bluth reports receiving personal fees from Comen Electronics Technology Co, Ltd; Dr Neto reports receiving personal fees from Drager; Dr Gama de Abreu reports receiving grants and personal fees from Drӓgerwerk AG and GlaxoSmithKline as well as personal fees from GE Healthcare.

Reference

Bluth T, Serpa Neto A, Schultz MJ, Pelosi P, Gama de Abreu M; for the Clinical Trial Network of the European Society of Anaesthesiology. Effect of intraoperative high positive end-expiratory pressure (PEEP) with recruitment maneuvers vs low PEEP on postoperative pulmonary complications in obese patients: a randomized clinical trial [published online June 3, 2019]. JAMA. doi:10.1001/jama.2019.7505