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

Abstract

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.

Keywords: Obstructive sleep apnea; anesthesia.; bariatric surgery; obesity; oximetry.

Fig. (1)

Means and standard deviations of peripheral oxygen saturation (SpO₂) before and during induction of anesthesia. In the sitting and supine positions, patients with history of OSA was significantly lower SpO₂. Nadir SpO₂ was remarkably lower in patients without history of OSA.

Fig. (2)

Nadir peripheral oxygen saturation (SpO2) during induction of anesthesia. Box plots of quartiles (boxes), median (line within box), 10^th, and 90^th percentiles (error bars, outliers’ ID is given as open circles). Median of nadir oxygen saturation is significantly higher in patients with a history of OSA.