In Vivo Aerodynamic Modeling of the Upper Airway in OSA

Drug-induced sleep endoscopy (DISE) was developed in 1991 as a technique to characterize upper airway collapse in patients with OSA. With the advent of various upper airway surgeries introduced in recent years, DISE has become increasingly utilized by the sleep surgeon as a surrogate for airway collapse during natural sleep in order to tailor a surgical approach for each patient. Propofol and/or midazolam infusions are typically used for sedation in these cases, however, there is limited evidence to suggest that these anesthetics reproduce natural sleep architecture. Therefore, it cannot be assumed that the pattern of collapse observed during DISE is reflective of natural sleep.

The aim of this study is to validate whether the pattern of collapse recorded during DISE mirrors that of natural sleep. Furthermore, the investigators aim to develop a quantitative in vivo model for airway collapse in order to further our understanding of the pathophysiology of OSA. They will do this by comparing the findings from DISE with aerodynamic readings from within the upper airway during natural sleep. The proposed technique will employ technologies already approved by the FDA for clinical use. Capacitance circuitry, airflow sensors, and/or pressure transducers will be suspended within the upper aerodigestive tract along a thin, low-profile, and flexible tube. During Phase I of the study, this aerodynamic probe will be placed in the OR during DISE along the upper airway, namely in the retropalatal, retroglossal, and hypopharyngeal regions. Readings will be correlated and calibrated with DISE findings in real-time. During Phase II, these sensors will again be placed within the same patients during in-office sleep studies. The results from the sleep study will be analyzed in conjunction with OR findings in order to create an aerodynamic model for natural sleep. This will also allow the investigators to assess whether airway observations during DISE were valid representations of natural sleep.