Obstructive sleep apnea (OSA) is characterized by recurrent upper airway obstruction due
to inadequate muscle tone during sleep leading to nocturnal hypercapnia, repeated
oxyhemoglobin desaturations and arousals. Continuous positive airway pressure (CPAP) is
the therapeutic mainstay for OSA, but adherence remains poor.
Currently, there exist 3 classes of surgical therapy for OSA, each addressing a specific
pathologic structure: skeletal surgery (target: jaw bones), neurostimulation (target:
tongue), and soft tissue (target: soft palate). Unfortunately, there is a critical
knowledge gap in terms of accurately identifying a patient's underlying mechanism of
obstruction; as a result, the efficacy of surgical treatment is limited.
Drug-induced sleep endoscopy (DISE) represents an opportunity to evaluate the upper
airway in sleep-like conditions. In its current clinical form, however, DISE does not
routinely determine the functional impact of anatomic and neuromuscular factors on
airflow obstruction. In June 2020, the investigators implemented a pilot protocol (IRB #
833511) to utilize measures of airflow, pressure catheters, and ultrasound to enhance
DISE exams. Over the course of 100 patients, they refined the research protocol to
generate a safe, efficient, and comprehensive physiologic exam of the upper airway in the
clinical setting (Dedhia et al, ORL, 2021, in press).
Upper airway pressure-flow and pressure-area relationships will be characterized during a
standard-of-care DISE by stepping through a range of nasal pressure (CPAP) levels to
derive functional determinants of upper airway obstruction during sleep. The
investigators' preliminary work in this area has shown patients requiring lower pressures
to restore airflow experience improved outcomes with neurostimulation surgery. Their
overall hypothesis is that upper airway pressure-flow/area relationships can be used to
predict response to all 3 major classes of sleep surgery: skeletal, neurostimulation, and
soft tissue. They will address this hypothesis by characterizing upper airway
pressure-flow and pressure-area relationships while utilizing objective anatomic
measurements from CT and ultrasound. These findings will allow investigators to
streamline the upper airway exam during DISE, and will further the goal of developing
personalized solutions that address specific pathogenic mechanisms of pharyngeal collapse
and airflow obstruction during sleep.
