Comparative Analysis of Drug-Induced Sleep Endoscopy With Positive Airway Pressure and Therapeutic Continuous Positive Airway Pressure in the Treatment of Obstructive Sleep Apnea

Abstract

Drug-induced sleep endoscopy (DISE) is a sedated upper airway exam to assess collapse patterns contributing to obstructive sleep apnea (OSA). DISE is often performed for patients intolerant to CPAP who are exploring surgical alternatives such as hypoglossal nerve stimulation (HGNS), an implantable device that stimulates the hypoglossal nerve to maintain airway patency during sleep [1]. Recent advancements in therapeutic nasal positive airway pressure (PAP) during DISE (DISE-PAP) suggest that lower palatal opening pressures correspond to HGNS response [2]. DISE-PAP has offered improvements in patient selection for surgery and in troubleshooting residual AHI following CPAP therapy [3, 4]. However, DISE-PAP remains underutilized due to its novelty and limited availability. Considering that patients undergo a trial of CPAP prior to surgery, therapeutic pressures during CPAP may serve as a readily available surrogate for DISE-PAP pharyngeal opening pressure (PhOP). This study investigates the correlation between CPAP therapeutic pressures from home AutoPAP data and PhOP during DISE-PAP.

A retrospective review of patients with OSA at a single institution who underwent DISE-PAP and had CPAP device data available between June 2023 and May 2024 was performed. DISE-PAP PhOP was defined as the CPAP pressure at which the airway was visually open at all levels. Home CPAP therapeutic pressures (95th percentile) were obtained via ResMed data download reports. Patients with residual AHI > 10 events/hour were excluded. A subanalysis was conducted by CPAP mask type (full face mask, nasal mask, and nasal pillow). Paired t-tests and Spearman correlation were performed using R Studio. Institutional review board approval and informed consent were secured per institutional guidelines.

Thirty-three patients (mean age 57 years, 73% male, 69% Caucasian, mean BMI 30.7 kg/m²) were included (Table 1). The mean baseline AHI was 30.2 (SD = 16.8) events/hour. The average PhOP was 8.4 cmH₂0 (SD = 4.0) compared to the average CPAP therapeutic pressure of 10.5 cmH₂ (SD = 3.0). PhOP was within 3.5 cmH₂O of CPAP therapeutic pressure in 20 patients (61%) and within 2 cmH₂O in 14 patients (42%). However, PhOP was not significantly correlated to CPAP therapeutic pressure (rho = −0.033, p = 0.86), even after adjusting for AHI, BMI, and CPAP mask type.

This lack of correlation between DISE-PAP PhOP and CPAP therapeutic pressures may be due to factors beyond sample size, such as fundamental differences between the two measurements. PhOP represents a one-time measurement under sedation, whereas CPAP pressures are adjusted over time to maintain airway patency during varying sleep stages. Institutional differences in DISE-PAP protocols, such as automatic vs. manual up-titration, may also affect PhOP measurements. Moreover, Mask type also impacts PAP outcomes, as prior studies suggest nasal masks optimize airway stability [4, 5]. While a nasal CPAP mask is used to perform DISE-PAP at our institution, patients often use different mask types at home, leading to potential discrepancies. Moreover, mask leaks may increase the pressure requirements at home, which may not be reflected in DISE-PAP's controlled environment [6]. Additionally, DISE-PAP is performed in a supine, sedated state, which may not capture natural positional airway changes [7].

Despite these limitations, CPAP therapeutic pressures warrant further investigation as a tool for refining surgical candidacy. Although CPAP is the first-line treatment for OSA, adherence rates range from 17% to 54% [8]. Identifying predictors of surgical outcomes is critical as surgical options expand. Although DISE-PAP has improved patient selection, there is a need to identify accessible correlates like CPAP pressures which may serve as a low-cost adjunct as its utilization grows. Future research should involve larger, prospective studies with stratification by mask type to clarify the role of CPAP therapeutic pressures in surgical planning.

This study did not identify a significant correlation between CPAP therapeutic pressures and PhOP measured through DISE-PAP. However, this may be attributed to the study's novel approach and limited sample size. Despite this, CPAP pressures could serve as a low-cost adjunct to DISE in assessing surgical candidacy. Further investigation through prospective studies with a larger, more robust sample size is encouraged to elucidate the role of CPAP parameters in guiding patient selection for sleep surgery.

This article was presented at the 2024 AAO-HNSF Annual Meeting & OTO Experience; September 28–October 1; Miami, Florida.

This study received approval from the Institutional Review Board at Thomas Jefferson University.

M.B. reports being the Chief Medical Officer of Nyxoah. C.H. reports research support for Inspire and Nyxoah; consulting support for Inspire, Nyxoah, and Aviomed.