Undiagnosed Obstructive Sleep Apnea and Postoperative Outcomes: A Prospective Observational Study

Abstract

Background: The prevalence of undiagnosed obstructive sleep apnea (OSA) during preoperative evaluation and the best method to screen OSA and its association with postoperative complications remain unclear. Objectives: To determine the prevalence of undiagnosed OSA in preoperative Indian patients undergoing noncardiac surgery, to compare the diagnostic accuracy of the STOP-BANG questionnaire to a preoperative level III sleep study, and to assess the association of OSA with postoperative complications. Methods: A prospective cohort of 245 consecutive adults with ≥2 risk factors for OSA who underwent noncardiac surgery between July 2011 and February 2013 were studied. The STOP-BANG questionnaire was administered to all patients, and 182/245 (74.2%) patients underwent a preoperative level III sleep study. Patients were followed for postoperative complications in hospital and contacted at 30 days after surgery. Results: 70/182 (38.5%) obtained a new diagnosis of OSA, including 11/182 (6%) with moderate to severe OSA (apnea-hypopnea index ≥15/h). On logistic regression analyses, the presence of OSA was independently associated with postoperative oxygen desaturation (OR 5.96, 95% CI 2.35-15.1, p < 0.01), a postoperative complication within 7 days (OR 3.63, 95% CI 1.77-7.45, p < 0.01) and within 30 days (OR 3.5, 95% CI 1.74-7.1, p < 0.01). The STOP-BANG questionnaire did not identify 12/70 (17%) of the patients diagnosed with OSA and classified 28% of the cohort as OSA when the level III sleep study was negative. Conclusions: Unrecognized OSA is common in preoperative patients and is independently associated with postoperative complications. The STOP-BANG questionnaire had a lower performance in the diagnosis of OSA in a South Indian population than the level III sleep study.

Sleep Study and Oximetry Parameters for Predicting Postoperative Complications in Patients With OSA

“…21 Among studies reporting postoperative complications in patients with OSA, 19 studies reported on AHI, five on ODI, two on CT90, five on minimum SpO 2 , one on mean SpO 2 , and one on longest apnea duration ( Table 1). 22 The majority of studies measured short-term postoperative adverse outcomes (< 72 h). The most frequently observed events included oxygen desaturations and requirements for supplemental oxygen in the postanesthetic care unit.…”

“…However, an association has been shown between a higher AHI and increased postoperative events (Table 1). 22 Among patients with diagnosed OSA, the mean AHI in the postoperative complications groups ranged from 37 to 68 events per hour. The majority of this evidence was based on patients undergoing upper airway corrective surgery for OSA.…”

“…Of the 19 studies reporting postoperative complications and preoperative AHI, 12 showed significant associations between AHI and postoperative complications ( Table 1). 22 These studies evaluated diverse populations undergoing surgery. A number of studies were performed in patients undergoing upper airway surgery for OSA.…”

“…Four studies were identified that used preoperative overnight oximetry to evaluate postoperative complications associated with an increased ODI ( Table 1). 22 ODI is defined as the number of occurrences of an SpO 2 decrease by 3% or 4% (desaturation criteria vary from 3% to 4%) from baseline per hour. In a study of 172 patients undergoing general surgery, Hwang et al 37 patients undergoing cardiac surgery by using preoperative nocturnal oximetry to diagnose sleep apnea.…”

Clinical Practice Guidelines for the Perioperative Nutrition, Metabolic, and Nonsurgical Support of Patients Undergoing Bariatric Procedures – 2019 Update: Cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic and Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists

“…(2019*). Studies have shown prolonged hospital stays and higher complication rates after bariatric surgery in patients with OSA . Hence, routine preoperative clinical screening for OSA with confirmatory polysomnography may be considered, with further diagnostic testing and treatment of appropriate at‐risk patients .…”