Changing Upper Airway Collapsibility via Mouth Closure During DISE-PAP

Introduction: The influence of mouth opening in the pathogenesis of obstructive sleep apnea (OSA) is still debated. Drug-induced sleep endoscopy with positive airway pressure (DISE-PAP) titration enables objective measurement of upper airway collapsibility. Herein, we examined the effect of mouth closure on metrics of pharyngeal collapsibility during DISE-PAP titration.

Methods: This is a prospective cohort study of PAP-alternative patients undergoing DISE-PAP between June 2020 and June 2022. Patients underwent two PAP-titration runs during DISE, one with the mandible in natural position, and another after a chin-lift maneuver without head or neck extension. Pharyngeal critical pressure (PCRIT) and pharyngeal opening pressure (PhOP) were obtained before and after mouth closure. Paired t-tests were used to evaluate whether there were significant changes in collapsibility.

Results: Forty-eight patients underwent DISE-PAP titrations before and after the mouth closure maneuver. On average, patients were middle-aged (55.7+/-14.6 years), overweight-obese (29.5+/-4.1 kg/m2), and 73% were males. Mouth closure led to significant reductions in both PCRIT (mean [95% CI] change = -2.25 [-3.77,-0.74] cmH2O; p=0.005) and PhOP (-1.69 [-2.72, -0.67] cmH2O; p=0.002). Mouth closure decreased PhOP and PCRIT values for 62.2% and 65.2% of patients, respectively.

Conclusions: Our data indicate that mouth closure decreases upper airway collapsibility during drug-induced sleep. However, instead of improvement, approximately one-third of patients responded with an increase in collapsibility. Further work is required to establish anatomical predictors of the strength and direction of collapsibility responses.