Risk stratification for postoperative hypoxemia among bariatric surgery patients.

Background: Patients with obesity, especially those suffering from obstructive sleep apnea (OSA), are prone to postoperative respiratory hypoxemia. The PRODIGY (prediction of opioid-induced respiratory depression in patients monitored by capnography) Score is used to predict respiratory complications that factor in sleep-disordered breathing. Data on the impact of OSA on the frequency and timing of postoperative desaturation trends after bariatric surgery are lacking.

Methods: This cohort study included 195 patients who underwent robotic-assisted bariatric surgery between June 2022 and December 2023. Patients underwent were classified by OSA status (yes/no) and PRODIGY Risk Score (high/intermediate/low). All patients received low or opioid sparing anesthesia and were continuously monitored postoperatively using the Masimo Rad-97 device (Masimo, Irvine, CA, USA). Postoperative monitoring averaged 14.5 hours, including tracking several variables and SpO2 values. We documented desaturations and opioid usage in 2-hour intervals. Patients also underwent 30-day postoperative follow up. Descriptive statistics were analyzed based on OSA status and PRODIGY scores using Student's t-test, ANOVA, and Fisher's Exact Test.

Results: Most study patients (57.4%) had OSA, were significantly older, and were predominantly female. Patients with OSA had substantially more prolonged exposure to SpO2 ranges between 80-95% and experienced more frequent desaturation events between 10 and 14 hours after Post-Anesthesia Care Unit (PACU) discharge. Patients with high PRODIGY scores (>15) had significantly more desaturation events compared to intermediate and low-score groups.

Conclusions: Postoperative desaturation rates are significantly higher among patients with OSA with high PRODIGY scores, especially in the delayed postoperative period. Continuous extended postoperative monitoring is warranted for these high-risk patients after bariatric surgery.