Effect of pharyngeal wall compliance on passive collapsibility of retropalatal airway in patients with obstructive sleep apnea

Abstract

Objective: To evaluate the pharyngeal compliance of patients with obstructive sleep apnea with complete muscle relaxation. And to study the relationship between the pharyngeal wall compliance and the mechanical load of the retropalatal airway.

Methods: The static mechanical load of the retropalatal pharynx was determined by critical closing pressure (P_crit) of the segment during general anesthesia in 30 patients. The size/dimensions of the pharynx were measured while intraluminal pressure was controlled at 3–20 cmH₂O.

Results: A total of 30 participants (age: 37.6 ± 7.6 years, 27 males) were studied. The mean apnea-hypopnea index was 51.6 ± 23.9 events/h. The retropalatal mean P_crit was 12.68 ± 4.13 cmH₂O. There was a significant difference in the length of the obstruction segment (F = 26.028, p < 0.001) among groups with different pharyngeal collapsibility. The correlation between the mechanical load of retropalatal airway and pharyngeal compliance in the level of the hard palate (r = −0.448, p = 0.015) and the uvula level (r = −0.462, p = 0.026) were significant.

Conclusions: Increased retropalatal mechanical loads were related to abnormal passive compliance of the pharyngeal wall. The contribution of each pharyngeal wall to airway collapse was varied.

Keywords

obstructive sleep apnea / P_crit / pharyngeal compliance / upper airway

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