Factors determining collapsibility of the human upper airway during sleep and general anaesthesia

Funded Activity Summary

Obstructive sleep apnoea (OSA) is common, affecting between 2-4% of middle-aged adults. It is characterised by repetitive partial or complete collapse of the upper airway during sleep. Each episode is accompanied by transient hypoxemia, hypertension and arousal. The repetitive arousals disrupt sleep resulting in excessive daytime tiredness and lethargy, which have major consequences for social well-being and productivity in our community. OSA is an independent risk factor for vascular disease. Central to understanding OSA is knowledge of the mechanisms responsible for vulnerability to upper airway collapse. It remains unclear to what extent this vulnerability relates to abnormalities in the underlying structure and passive physical characteristics of the upper airway, versus abnormalities in activity of upper airway muscles. Making this distinction has been problematic because current methods of testing upper airway collapsibility in sleeping humans tend to result in changes in muscle activity and-or sleep state, affecting the measurements. It is, however, possible to suppress upper airway muscle activity and eliminate measurement-related changes in muscle activity and state with general anaesthesia, while maintaining normal spontaneous breathing. We have developed and refined this method and propose to use it in novel investigations to (a) relate the behaviour of the flaccid airway (no muscle activity) under anaesthesia to its behaviour during sleep (when muscle activity is variable but quantifiable), and (b) determine the effect of changes in body habitus (posture and lung volume) on airway collapsibility. These studies will allow examination of the exciting possibility that measurements made under brief general anaesthesia could be used to define propensity to obstruction during sleep. They will also allow examination of the contribution of common changes in body habitus toward vulnerability to upper airway collapse.

Funded Activity Details

Start Date: 01-01-2004

End Date: 01-01-2006

Funding Scheme: NHMRC Project Grants

Funding Amount: $259,625.00

Funder: National Health and Medical Research Council

Research Topics

ANZSRC Field of Research (FoR)

Respiratory Diseases

ANZSRC Socio-Economic Objective (SEO)

There are no SEO codes available for this funding activity

Other Keywords

daytime sleepinessand fatigue | diagnosis of upper airway dysfunction | genioglossus muscle | obstructive sleep apnoea | sleep and general anaesthesia | somnolence | upper airway | upper airway collapse

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