Polysomnography in pre-operative screening for obstructive sleep apnea in patients undergoing bariatric surgery: a retrospective cohort study.

Background/objectives: To assess the impact of obstructive sleep apnea (OSA) screening with polysomnography on preventing cardiovascular and pulmonary complications in the postoperative period of bariatric surgery.

Subjects/methods: This was a single-center retrospective cohort study, including 522 adults who underwent bariatric surgery between August 2010 and May 2019. Electronic medical records were accessed to obtain variables of interest. Screening for OSA was performed as a medical indication and registered as positive if apnea-hypopnea index was ≥5 events/hour in patients who did not have previous OSA diagnosis. The primary outcome was the presence of cardiac or pulmonary events in the 30-day postoperative period. Secondary outcomes included length of stay (days), need for an intensive care unit (ICU) after surgery, length of mechanical ventilation, and time from mechanical ventilation withdrawal. Statistical analyses were performed with χ, Fisher's exact test, Student's t-test, Mann-Whitney U test, and Poisson regression.

Results: Most participants (n = 326) did not have OSA screening with polysomnography, while 196 had performed this screening. There was no difference in cardiopulmonary events between the screening and non-screening groups (4.2% vs. 2.8%; P = 0.45). Polysomnography screening could not reduce cardiovascular or pulmonary complications in the postoperative period, RR = 1.73 (95% CI: 0.68-4.14). There was no difference in ICU admission, length of stay, and time from mechanical ventilation between groups in secondary outcomes.

Conclusions: Our study suggests that OSA screening with polysomnography in the pre-operative care of bariatric surgery is a dispensable procedure, as it does not change postoperative cardiopulmonary outcomes. Indications for polysomnography should be made at the individual level.