Different PEEP Methods Create Similar Outcomes for Patients With Obesity

There is no significant difference in outcomes between the use of positive end-expiratory pressure (PEEP) of more than 5 cm H₂O and PEEP of 5 cm H₂O or less in patients with obesity who receive procedures requiring general anesthesia and mechanical ventilation, according to a report published in Obesity (Silver Spring).

Investigators in the United States conducted a review to assess the efficacy of PEEP of more than 5 cm H₂O in preventing intraoperative atelectasis in patients with obesity and found little difference in outcomes.

Data from 4 randomized controlled trials were analyzed, which included a total of 2116 participants. The selected studies all included participants who had a body mass index (BMI) of greater than 30 and were aged 18 years or older, who had received mechanical ventilation with general endotracheal anesthesia, had low tidal volume of 6 to 8 mL/kg of predicted body weight, and who received procedures of 2 hours in duration. Studies included direct comparison between the use of high PEEP (>5 cm H₂O) with low PEEP (1-5 cm H₂O).

The authors defined complications as postoperative pulmonary complications (PPC), including acute respiratory distress syndrome, atelectasis, bronchospasm, cardiopulmonary edema, new pulmonary infiltrates, pleural effusion, pneumonitis, pneumothorax pulmonary infection, and respiratory failure.

The authors additionally looked at secondary measures, including extrapulmonary complications, intraoperative hypotension, need for vasoactive medications, duration without hospital readmission, and mortality during a hospital stay.

The authors used Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines and employed the Covidence review manager when selecting studies. They employed the Cochrane ReviewManager (RevMan) version 5.4 for analysis. Multiple statistical analyses were used for data, including subgroup analyses of laparoscopy versus laparotomy and tobacco smoking versus no tobacco smoking.

The researchers found no statistically significant difference in the incidence of PPCs between the PEEP of 5 cm H₂O or less and PEEP of more than 5 cm H₂O groups (risk ratio, 2.21 [95% CI, 0.41-11.83; P = .35]). They identified significant heterogeneity within included studies (I² = 53%).

According to the investigators, the heterogeneity of PPCs between studies was a significant study limitation, which may affect the validity of this report’s statistical results.

“It is unclear whether PEEP of more than 5 cm H₂O improves the postoperative clinical outcome in patients with obesity, which is in contrast to previously established evidence that it reduces atelectasis in patients with obesity,” the study authors wrote. They indicated there is a need for additional research on the comparative effects of low- and high-level PEEP in individuals with obesity.