DENVER — All candidates for gastric bypass surgery should be evaluated for obstructive sleep apnea, Brian Abaluck, M.D., said at the annual meeting of the Associated Professional Sleep Societies.
The prevalence of this sleep disorder is extremely high among the morbidly obese. Indeed, Dr. Abaluck reported that the rate was 70% in a series of 139 consecutive patients scheduled for gastric bypass surgery who underwent overnight polysomnography and completed the Epworth Sleepiness Scale and the Multivariable Apnea Prediction questionnaire.
It's important to identify and treat affected patients because obstructive sleep apnea (OSA), if untreated prior to gastric bypass surgery, can cause numerous perioperative complications, explained Dr. Abaluck of the University of Pennsylvania, Philadelphia.
Particularly striking in this patient series was the high rate of REM-related obstructive sleep apnea as defined by an apnea-hypopnea index (AHI) higher than 10 during REM sleep and an AHI higher than 20 during non-REM sleep. REM-related OSA was diagnosed in 78% of patients and was rated as severe in 44% of the study population. Of note, in many patients with severe REM-related obstructive sleep apnea, the total AHI was only mildly elevated.
The higher a patient's body mass index, the greater the apnea-hypopnea index tended to be. A higher AHI also correlated with a higher Multivariable Apnea Prediction score and with female gender. However, no correlation was found between body mass index and the score on the Epworth Sleepiness Scale.
Dr. Abaluck and his colleagues are now trying to identify screening tools that will permit more selective use of overnight polysomnography—which is costly and inconvenient—in patients preparing for gastric bypass surgery.