Pharyngeal Manometry and Upper Airway Collapse During Drug-Induced Sleep Endoscopy

Abstract

Importance: Drug-induced sleep endoscopy (DISE) is used to guide therapeutic management of obstructive sleep apnea (OSA), depending on the levels and patterns of pharyngeal collapse. However, the collapsibility of specific pharyngeal sites remains unknown.

Objective: To assess collapse sites in patients with OSA undergoing DISE and whether number and location are associated with differences in airway collapsibility; and to quantify differences in collapsibility between primary and secondary sites in multilevel collapse.

Design, setting, and participants: This cohort study assessed adult patients (≥18 years) with OSA undergoing DISE with manometry and positive airway pressure (PAP) titration at a tertiary care center from November 2021 to November 2023. Patients with an AHI score greater than 5 were included; those with less than 1 apnea event during DISE or incorrect catheter placement were excluded. Data were analyzed from September 28, 2022, to March 31, 2024.

Exposure: DISE with manometry and PAP titration.

Main outcomes and measures: Active pharyngeal critical pressure (Pcrit-A) and pharyngeal opening pressure (PhOP) were used to quantify airway collapsibility, adjusted for covariates (age, sex, race, and body mass index [BMI]).

Results: Of 94 screened, 66 patients (mean [SD] age, 57.4 [14.3] years; BMI, 29.2 [3.9]; 51 [77.3%] males) with a mean (SD) apnea-hypopnea index (AHI) of 31.6 (19.0) were included in the analysis. Forty-seven patients (71.2%) had multilevel collapse, 10 (15.2%) had single-level nasopalatal collapse, and 9 (13.6%) had single-level infrapalatal collapse. Groups did not differ in demographic characteristics or established measures of OSA severity. The single-level nasopalatal group had substantially elevated levels of airway collapsibility (Pcrit-A and PhOP covariate adjusted mean, 2.4; 95% CI, 1.1 to 3.8; and 8.2; 95% CI, 6.4 to 9.9 cmH2O) compared to the single-level infrapalatal group (-0.9; 95% CI, -2.4 to 0.5 cmH2O; and 4.9; 95% CI, 3.0 to 6.8 cmH2O, respectively) and similar to the level among the multilevel group (1.3; 95% CI, 0.7 to 2.0; and 8.5; 95% CI, 7.7 to 9.3 cmH2O). The multilevel group had more negative inspiratory pressure (-24.2; 95% CI, -28.1 to -20.2 cmH2O) compared to the single-level nasopalatal group (-9.8; 95% CI, -18.3 to -1.28 cmH2O). In patients with multilevel collapse, airway collapsibility was significantly higher at the primary nasopalatal compared to secondary infrapalatal site (mean difference, 13.7; 95% CI, 11.3 to 16.1 cmH2O).

Conclusions and relevance: The findings of this cohort study suggest that intervention should target the primary site of pharyngeal collapse, and secondary sites only if they are nearly as collapsible as the primary site. Future work is needed to precisely define the difference in primary and secondary collapsibility that necessitates multilevel treatment.

Figure 1.. Endoscopic, Manometric and Physiologic Study Methods

A, Sagittal drawing of pharyngeal catheter placement showing catheter placed just distal to the soft palate (green) obtained nasopalatal pressure (P-NP), while the catheter posterior to the epiglottic petiole in the supraglottic space (blue) obtained infrapalatal pressure (P-IP). B, Endoscopic image showing the location of each catheter within the airway. C, Illustrative pressure-flow curve obtained during drug-induced sleep endoscopy, where active pharyngeal critical pressure (Pcrit-A) is the highest pressure without nasal airflow and pharyngeal opening pressure (PhOP) is the lowest nasal mask pressure with nonflow-limited breathing. TB indicates tongue base, and e, epiglottis.

Figure 2.. Differences Between Collapse Pattern Groups

Differences between collapse pattern groups with 95% CIs for active pharyngeal critical pressure (Pcrit-A), pharyngeal opening pressure (PhOP), and peak inspiratory pressure (P-IP) nadir, adjusted for age, sex, race, and BMI. IP indicates single-level infrapalatal; NP, single-level nasopalatal; ML, multilevel. ^aTable 2 shows between-group effect sizes and 95% CIs for comparisons.

Figure 3.. Collapsibility of Primary Nasopalatal and Secondary Infrapalatal Pharyngeal Sites

Collapsibility of primary nasopalatal and secondary infrapalatal pharyngeal sites in patients with multilevel collapse, adjusted for age, sex, race, and BMI, demonstrated a broad range of collapsibility at the secondary infrapalatal site. Note that the IP site can resist collapse in some patients down to markedly negative intraluminal pressures (P-IP′ less than −10 to −40 cmH₂O), well outside the normal physiologic inspiratory pressure range. BMI indicates body mass index calculated as weight in kilograms divided by height in meters squared; IP, single-level infrapalatal; Pcrit-A, active pharyngeal critical pressure; and P-IP′, secondary infrapalatal collapse pressure.