Do Patients with Obstructive Sleep Apnea have an Increased Risk of Desaturation During Induction of Anesthesia for Weight Loss Surgery?

BACKGROUND Obstructive sleep apnea (OSA) is an independent risk factor to develop perioperative complications during weight loss surgery, but the mechanisms are unclear. It is possible, that patients with OSA have a higher incidence of desaturation during induction of anesthesia. METHODS We enrolled 100 morbidly obese (body mass index: 53+/-10) adult patients undergoing open bariatric surgery in a prospective study. At least 1 h before induction of anesthesia, peripheral oxygen saturation (SpO(2)) was measured by an oximetry finger probe in the sitting and supine positions, and Mallampati score was taken. Oxygen saturation was recorded also during induction of anesthesia, and nadir values were analyzed, and the STOP-BANG questionnaire was applied. RESULTS Thirty-six patients presented with clinical suspicion of OSA. Body weight predicted oxygen saturation in the supine and sitting position, prior to induction of anesthesia. Nadir oxygen saturation during induction of anesthesia was considerably higher in patients with clinical suspicion of OSA, a significant finding that persisted as a trend after correction for age, gender and BMI. The Mallampati score was an independent predictor of OSA, even in morbidly obese patients scheduled for weight loss surgery. CONCLUSIONS Morbidly obese patients presenting for weight loss surgery have a significant risk to desaturate during induction of anesthesia. A history of OSA does not independently increase the risk of desaturation during induction of anesthesia, if the appropriate precautions are being taken.