Airway changes in obstructive sleep apnoea patients associated with a supine versus an upright position examined using cone beam computed tomography

OBJECTIVE: This study aimed to describe total volume and cross-sectional area measurement changes in obstructive sleep apnoea patients associated with a supine versus an upright position. METHOD: A retrospective chart review of patients who underwent cone beam computed tomography in upright and supine positions was performed, and the images were analysed. RESULTS: Five obstructive sleep apnoea patients (all male) underwent both upright and supine cone beam computed tomography imaging. Mean age was 35.0 ± 9.3 years, mean body mass index was 28.1 ± 2.7 kg/m2 and mean apnoea-hypopnoea index was 39.3 ± 23.0 per hour. The airway was smaller when patients were in a supine compared with an upright position, as reflected by decreases in the following airway measurements: total volume; posterior nasal spine, uvula tip, retrolingual and tongue base (not significant) cross-sectional areas; and site of the minimum cross-sectional area (of the overall airway). Total airway volume decreased by 32.6 per cent and cross-sectional area measurements decreased between 32.3 and 75.9 per cent when patients were in a supine position. CONCLUSION: In this case series, the airway of obstructive sleep apnoea patients was significantly smaller when patients were in a supine compared with an upright position.