The optimal ventilation strategy during general anesthesia is unclear. This systematic review investigated the relationship between ventilation targets or strategies (eg, positive end-expiratory pressure [PEEP], tidal volume, and recruitment maneuvers) and postoperative outcomes.
PubMed and Embase were searched on March 8, 2021, for randomized trials investigating the effect of different respiratory targets or strategies on adults undergoing noncardiac surgery. Two investigators reviewed trials for relevance, extracted data, and assessed risk of bias. Meta-analyses were performed for relevant outcomes, and several subgroup analyses were conducted. The certainty of evidence was evaluated using Grading of Recommendations Assessment, Development and Evaluation (GRADE).
This review included 63 trials with 65 comparisons. Risk of bias was intermediate for all trials. In the meta-analyses, lung-protective ventilation (ie, low tidal volume with PEEP) reduced the risk of combined pulmonary complications (odds ratio [OR], 0.37; 95% confidence interval [CI], 0.28–0.49; 9 trials; 1106 patients), atelectasis (OR, 0.39; 95% CI, 0.25–0.60; 8 trials; 895 patients), and need for postoperative mechanical ventilation (OR, 0.36; 95% CI, 0.13–1.00; 5 trials; 636 patients). Recruitment maneuvers reduced the risk of atelectasis (OR, 0.44; 95% CI, 0.21–0.92; 5 trials; 328 patients). We found no clear effect of tidal volume, higher versus lower PEEP, or recruitment maneuvers on postoperative pulmonary complications when evaluated individually. For all comparisons across targets, no effect was found on mortality or hospital length of stay. No effect measure modifiers were found in subgroup analyses. The certainty of evidence was rated as very low, low, or moderate depending on the intervention and outcome.
Although lung-protective ventilation results in a decrease in pulmonary complications, randomized clinical trials provide only limited evidence to guide specific ventilation strategies during general anesthesia for adults undergoing noncardiac surgery.
- Question: Do specific ventilatory targets or strategies improve outcomes for patients undergoing general anesthesia for noncardiac surgery?
- Findings: In this systematic review and meta-analysis including 63 trials, we found that evidence to support specific ventilatory strategies during general anesthesia was limited. Methodological heterogeneity among trials was large.
- Meaning: Evidence to guide mechanical ventilation strategies during perioperative care is limited. Larger trials with less methodological heterogeneity are needed to inform clinical care.