Home sleep study nasal airflow patterns and epiglottic collapse during drug induced sleep endoscopy

Obstructive sleep apnea (OSA) is characterized by collapse of various portions of the pharynx. Epiglottic collapse is difficult to diagnose and may affect treatment tolerance. Previous research shows a distinct nasal airflow pattern during epiglottic obstruction characterized by signal discontinuities. It was hypothesized that primary epiglottic collapse characterized during drug-induced sleep endoscopy (DISE) correlates with nasal airflow discontinuity signals seen on home sleep studies.

Patients with clinical records of undergoing both DISE and home portable sleep studies with raw data available from December 2016 to August 2021 were screened for epiglottic collapse or no epiglottic collapse using the VOTE scoring system. Any patient with tongue base collapse was excluded. Characterization of nasal airflow signals as discontinuities was based on previously published data. Acute flow discontinuities were scored by two blinded observers (AS, JN) from home cardiorespiratory studies using nasal pressure cannulas (Apnea Link Plus). Breath statistics (total number of breaths and flow limited breaths) for each patient were captured by the home cardiorespiratory device. DISE was performed under propofol anesthesia to a Ramsay level 5. Epiglottic collapse was described by shape, direction (AP or lateral), and timing (prolonged or intermittent).

The home sleep studies and DISE of 18 patients being considered for surgical therapies were retrospectively analyzed. Patients included had either complete (n=11) or no epiglottic collapse (n=7). The mean AHI was 21.3 and 19.7, respectively. There was a significant difference between nonepiglottic and epiglottic collapse groups in the total discontinuity breaths (median 7 vs 29, p=0.002), discontinuity breaths/hour (median 0.91 vs 5.3, p=0.001), and fraction of discontinuity breaths over total flow limited breaths (0.5% vs 1.9%, p=0.001). Morphological changes in epiglottic collapse did not affect discontinuities.

The data from this study demonstrates nasal airflow signals from home sleep studies correlate with DISE epiglottic collapse.