Factors determining collapsibility of the human upper airway during sleep and general anaesthesia [ 2004 - 2006 ]

Research Grant

Researchers: Prof Peter Eastwood (Principal investigator) ,  Prof David Hillman

Brief description 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.

Funding Amount $AUD 259,625.00

Funding Scheme NHMRC Project Grants

Notes Standard Project Grant