Semirecumbent Positioning During Anesthesia Recovery and Postoperative Hypoxemia

Importance The efficacy of a semirecumbent position (SRP) in reducing postoperative hypoxemia during anesthesia emergence is unclear despite its widespread use. Objective To determine the differences in postoperative hypoxemia between patients in an SRP and a supine position. Design, Setting, and Participants This randomized clinical trial was performed at a tertiary hospital in China between March 20, 2021, and May 10, 2022. Patients scheduled to undergo laparoscopic upper abdominal surgery under general anesthesia were enrolled. Study recruitment and follow-up are complete. Interventions Patients were randomized to 1 of the following positions at the end of the operation until leaving the postanesthesia care unit: supine (group S), 15° SRP (group F), or 30° SRP (group T). Main Outcomes and Measures The primary outcome was the incidence of postoperative hypoxemia in the postanesthesia care unit. Severe hypoxemia was also evaluated. Results Out of 700 patients (364 men 52.0%; mean SD age, 47.8 11.3 years), 233 were randomized to group S (126 men 54.1%; mean SD age, 48.2 10.9 years), 233 to group F (122 men 52.4%; mean SD age, 48.1 10.9 years), and 234 to group T (118 women 50.4%; mean SD age, 47.2 12.1 years). Postoperative hypoxemia differed significantly among the 3 groups (group S, 109 of 233 46.8%; group F, 105 of 233 45.1%; group T, 76 of 234 32.5%; P = .002). This difference was statistically significant for groups T vs S (risk ratio RR, 0.69 95% CI, 0.55-0.87; P = .002) and groups T vs F (RR, 0.72 95% CI, 0.57-0.91; P = .007), but not for groups F vs S (RR, 0.96 95% CI, 0.79-1.17; P = .78). Severe hypoxemia also differed among the 3 groups (group S, 61 of 233 26.2%; group F, 53 of 233 22.7%; group T, 36 of 234 15.4%; P = .01). This difference was statistically significant for groups T vs S (RR, 0.59 95% CI, 0.41-0.85; P = .005). Conclusions and Relevance In this randomized clinical trial of SRP during anesthesia recovery in patients undergoing laparoscopic upper abdominal surgery, postoperative hypoxemia was significantly reduced in group T compared with group F or group S. Trial Registration Chinese Clinical Trial Registry Identifier: ChiCTR2100045087