To investigate the pathophysiology of sleep-related breathing disorders including obstructive sleep apnea and nocturnal asthma
Obstructive sleep apnea (OSA) occurs due to frequent partial or complete collapse of the pharyngeal airways during sleep. About 10% of general population have sleep apnea. OSA is associated with excessive daytime sleepiness, increased risk of heart disease, stroke, cognitive impairments, and work and car related accidents.
Asthma affects 8% of Canadians. It is characterized by intermittent airflow obstruction, cough, chest tightness, shortness of breath, and disability due to small airway inflammation and narrowing. Despite major advances in asthma treatments, 50% of asthmatics have frequent exacerbation of their symptoms during sleep. In fact, 53% of asthma attacks that led to death occur at night. And for unknown reasons, OSA is a major risk factor of nocturnal asthma.
Our goal is to investigate the mechanisms of pharyngeal and small airway narrowing in OSA and nocturnal asthma, respectively. In particular, we are interested in the role of recumbent posture, variations in hemodynamics, and physiological changes such as reductions in respiratory muscle tone on airway narrowing during sleep.
To develop convenient, accurate, and portable devices to monitor physiological signals during sleep
One of the main barriers to investigate why respiratory disorders become exacerbated during sleep is that the available technologies to perform studies are expensive, invasive, and interfere with breathing and sleep patterns. Therefore, the results may not be applicable to a wide range of people or over a long period of time to evaluate treatments and interventions. Our objective is to address this gap. Below are some examples of our research:
- Continuous measurement of fluid volumes in various body segments such as legs, thorax and neck: This is the first system to measure neck fluid volume in real time non-invasively.
- A wearable device to monitor respiratory sounds: We developed novel algorithms based on respiratory sounds for acoustic estimation of respiratory airflow, assessing OSA severity, and estimating the amount of fluid in the neck. For the first time, we have developed an acoustic model of the pharynx as a collapsible tube for snoring sound generation. This research is supported by our industrial partner, BresoTec Inc.