Clinical polysomnographic methods for estimating pharyngeal collapsibility in obstructive sleep apnea

Abstract

Study Objectives Obstructive sleep apnea has major health consequences but is challenging to treat. For many therapies, efficacy is determined by the severity of underlying pharyngeal collapsibility, yet there is no accepted clinical means to measure it. Here we provide insight into which polysomnographic surrogate measures of collapsibility are valid, applicable across the population, and predictive of therapeutic outcomes. Methods Seven promising polysomnography-derived surrogate collapsibility candidates were evaluated: Vpassive (flow at eupneic ventilatory drive), Vmin (ventilation at nadir drive), event depth (depth of the average respiratory event), oxygen desaturation slope and mean oxygen desaturation (events-related averages), Fhypopneas (fraction of events scored as hypopneas), and apnea index. Evaluation included 1) validation by comparison to physiological gold-standard collapsibility values (critical closing pressure, Pcrit), 2) capacity to detect increased collapsibility with older age, male sex, and obesity in a large community-based cohort (Multi-Ethnic Study of Atherosclerosis, MESA), and 3) prediction of treatment efficacy (oral appliances and pharmacological pharyngeal muscle stimulation using atomoxetine-plus-oxybutynin). Results Pcrit was significantly correlated with Vmin (r=-0.54), event depth (r=0.49), Vpassive (r=-0.38), Fhypopneas (r=-0.46), and apnea index (r=-0.46; all p<0.01) but not others. All measures detected greater collapsibility with male sex, age, and obesity, except Fhypopneas and apnea index which were not associated with obesity. Fhypopneas, and apnea index were associated with oral appliance and atomoxetine-plus-oxybutynin efficacy (both p<0.05). Conclusions Among several candidates, event depth, Fhypopneas, and apnea index were identified as a preferred pharyngeal collapsibility surrogates for use in the clinical arena.

Variability in the response to atomoxetine and oxybutynin for OSA: Highlighting the need for personalized medicine

“…Indeed, support for this argument can also be gleaned directly from the polysomnographic data presented by Kinouchi et al In their study, the proportion of respiratory events 9 that were hypopnoeas (Fhypopnoeas) was approximately 40%. By contrast, the Fhypopnoeas in the Taranto‐Montemurro et al trial was ~85%.…”

“…By contrast, the Fhypopnoeas in the Taranto‐Montemurro et al trial was ~85%. Notably, Vena et al have recently demonstrated that this polysomnographic measure can be used as a surrogate measure for airway collapsibility (i.e., the lower the proportion, the more collapsible the airway) 9 . Furthermore, while there was no clear reduction in the total AHI in the Kinouchi study, there was a significant increase in the fraction of respiratory events that were hypopneas (or reduction in proportion of apnoeas).…”

Atomoxetine and fesoterodine combination improves obstructive sleep apnoea severity in patients with milder upper airway collapsibility

“…V ACTIVE was defined as the level of ventilation at maximum drive (i.e., arousal threshold). V MIN 20 was the ventilation at the lowest drive (i.e., first decile). All traits, except for loop gain, which is dimensionless, were expressed as percent of V EUPNOEA , namely unobstructed ventilation during sleep at normal ventilatory drive (see Figure 2, right panel).…”

A single dose of noradrenergic/serotonergic reuptake inhibitors combined with an antimuscarinic does not improve obstructive sleep apnoea severity

“…V passive is the level of ventilation at eupneic ventilatory drive and reflects the passive airway, while V active is the ventilation achieved just prior to the termination of a respiratory event when V drive is at its peak and the airway is maximally stimulated. The V min provides an alternative measure of collapsibility and is based on the ventilation observed at the minimal level of V drive (calculated from the lowest decile instead of median V eupnea , Vena et al, 2022 ). A lower value denotes a more collapsible airway.…”

“…How to cite this article: Thomson, L. D. J., Landry, S. A., Joosten, S. A., Mann, D. L., Wong, A-M, Cheung, T., Adam, M., Beatty, C. J., Hamilton, G. S., & Edwards, B. A.…”