Persistent Snoring Under Conscious Sedation During Colonoscopy is a Predictor of Obstructive Sleep Apnea

Background: Obstructive sleep apnea (OSA) is characterized by cessation of breathing during sleep. Conscious sedation (CS) induces sleep and may uncover sleep-related breathing disorders.

Objective: To determine whether snoring during CS is a sensitive predictor of OSA.

Design: Matched cohort study.

Setting: University-based ambulatory endoscopy center.

Patients: Consecutive patients undergoing colonoscopy completed a detailed sleep questionnaire and physical examination geared toward detecting OSA (body mass index [BMI], neck circumference, and the presence of craniofacial abnormalities). The endoscopist was blinded to the information.

Interventions: Portable nocturnal polysomnography.

Main Outcome Measurements: Patients who snored during CS in the left lateral decubitus position for 10 seconds or longer were referred for polysomnography. Sex- and BMI-matched patients who did not snore served as control subjects.

Results: A total of 131 patients were enrolled, and 24 (18.3%) of them snored. These patients (22 men, 2 women) had a predominance of Mallampati grade III/IV, higher Stanford and Epworth scale scores, and greater BMI and neck circumference and were more likely to report daytime sleepiness, decreased vigilance, and personality and mood changes (all P values <.05). All investigated patients who snored during CS had evidence of OSA versus 4 of 18 control subjects (mean apnea-hypopnea index: 40 events vs 5 events; P < .0001) (100% positive predictive value; 77.8% negative predictive value). Moderate or severe OSA was detected in 14 of 20 patients versus 1 of 18 control subjects (P < .001; 70% positive predictive value; 94.4% negative predictive value, 93% sensitivity, 74% specificity). Data obtained from sleep questionnaires and physical examination failed to accurately predict OSA.

Limitations: Single-center nature and relatively small number of patients developing the outcome variable.

Conclusions: Snoring during CS is a strong predictor of OSA. Given the medical and financial burden of undiagnosed OSA, these patients should be carefully identified and referred for sleep medication evaluation.