DISE and Rhinomanometry Correlates of Response to Head-of-Bed Elevation in Obstructive Sleep Apnea

To identify endoscopic and rhinomanometric correlation of response to 30° head-of-bed elevation (HOBE) in patients with obstructive sleep apnea (OSA), and to explore whether upper airway (UA) collapse patterns and nasal resistance are associated with positional improvement.

We assessed the associations between drug-induced sleep endoscopy (DISE) findings and rhinomanometric parameters with response to HOBE in OSA patients. Polysomnography was performed overnight in standardized supine, 30° HOBE, and lateral positions. HOBE response was evaluated based on percent change in apnea-hypopnea index (AHI), and correlations with VOTE collapse patterns and nasal resistance were determined.

HOBE significantly reduced AHI from 22.6 ± 5.7 to 16.4 ± 4.9 events/h (p < 0.001), with further lateral position reduction (11.7 ± 4.2, p < 0.001). OSA patients demonstrated greater AHI improvement with HOBE than controls (-31.0% vs. -14.0%, p < 0.001). Expiratory nasal resistance was significantly elevated in OSA patients (p < 0.001) and strongly correlated with percent AHI change during HOBE (r = 0.912, p < 0.001). VOTE analysis revealed more severe multilevel collapse in OSA patients; epiglottic (r = 0.903) and tongue base collapse scores (r = 0.714) were strongly associated with the HOBE response. After adjustment for BMI and sex, epiglottic and velar collapse scores remained significantly associated with HOBE response, whereas rhinomanometric associations were attenuated and no longer statistically significant.

DISE findings and expiratory rhinomanometric resistance values may help characterize positional responsivity to HOBE including patterns of UA collapse as well as nasal airflow resistance. However, results should be considered hypothesis-generating and require confirmation in larger cohorts with prospective data collection, formal model development, and external validation.