Repeatability of Pharyngeal Opening Pressure Under Drug-Induced Sleep Endoscopy

Introduction: Pharyngeal opening pressure (PhOP) obtained during drug induced sleep endoscopy (DISE) has been associated with surgical outcomes in the treatment of obstructive sleep apnea (OSA). The stability of PhOP during the course of DISE remains unclear. The goal of this study is to compare repeat measures of PhOP during DISE.

Methods: This study is part of an ongoing IRB approved prospective clinical trial assessing the effects of negative pressure ventilation on airway collapse during DISE. As part of that protocol, patients (June 2022 - January 2023) had continuous positive airway pressure (CPAP) titration performed under DISE before and after the negative pressure ventilation run. PhOP measures were calculated for both CPAP runs and compared to each other using test re-test coefficient analysis. Additionally, sedation depth was measured from frontal EEG using the SedLine® Brain Function Monitoring and reported as the patient sedation index (PSI). A repeated measures correlation comparing average PSI and PhOP between CPAP runs was also performed to determine the influence of sedation depth on PhOP.

Results: Seventeen subjects completed the DISE evaluation. Mean time between CPAP runs was 11:52 minutes. Mean PSI of CPAP run 1 was 46.21 and run 2, 38.28 (p=0.17), respectively. Test-retest analysis showed excellent correlation of both PhOP values (ICC 0.91 p< 1^-08). Repeated measures correlation of thirteen subjects trended towards a negative correlation between PSI and PhOP, however this relationship is not statistically significant (r= -0.46, p-value 0.09).

Conclusions: DISE-PhOP is an objective and reproducible technique to measure airway collapse pattern and remains stable over time. Although there was a trend toward negative correlation between PSI and PhOP, it was not statistically significant. The results suggest that airway collapsibility under DISE remains relatively stable over the course of sedation.