Preoperative oximetry-derived hypoxemia predicts postoperative cardiovascular events in surgical patients with unrecognized obstructive sleep apnea

Obstructive sleep apnea (OSA) is known to be associated with postoperative cardiovascular events in patients undergoing major non-cardiac surgery. The objective of the study is to determine whether preoperative oximetry-derived hypoxemia predicts postoperative cardiovascular events in surgical patients with unrecognized obstructive sleep apnea.The study was a planned post hoc analyses of a multicenter prospective cohort study.The inclusion criteria were patients ≥45 years old undergoing major non-cardiac surgery with cardiovascular risk factors.All patients underwent pre-operative pulse oximetry (PULSOX-300i, Konica-Minolta Sensing, Inc). The severity of OSA was classified based on oxygen desaturation index (ODI) (mild: ≥5 to <15, moderate: ≥15 to <30, and severe OSA: ≥30 events/h). The 30 days cardiovascular events were a composite of myocardial injury, cardiac death, congestive heart failure, thromboembolism, atrial fibrillation, and stroke.For 1218 patients with mild, moderate, or severe OSA (mean age: 67.2 ± 9.3 years; body mass index: 27.0 ± 5.3 kg/m2), the rate of postoperative cardiovascular events was 16.4%, 25.2%, and 29.8% respectively. The multivariable analysis showed that preoperative oxygen desaturation index (ODI) ≥30 events per hour {adjusted hazard ratio (aHR) 1.63 [95% confidence interval (CI): 1.05-2.53]}, and cumulative time spent during sleep with oxygen saturation below 80% (CT80) ≥10 min {aHR 1.79 [95% CI: 1.28-2.50]} were independent predictors of 30-day postoperative cardiovascular events.Preoperative ODI ≥30 events per hour and CT80 ≥ 10 min are associated with increased risk of postoperative cardiovascular events. Preoperative screening using oximetry helps in risk stratification for unrecognized sleep apnea.ClinicalTrials.gov Identifier: NCT01494181.