Flow Dependence of Anatomical Dead Space: Effect of Lung Volume & Bronchodilation

In this study we further investigated the effect of expired flow on the measurement of airway volume (flow-dependence of anatomical dead space) by investigating the effect of lung inflation and inhaled asthma therapy (bronchodilators) in healthy and asthmatic subjects. In both subject groups we found the flow-dependence of dead space decreased at higher lung volumes. The effect of bronchodilators was to decrease the degree of non-uniform ventilation in the healthy group but to worsen it in our asthmatic subjects. The latter finding suggests inhaled bronchodilators are preferentially distributed to lung regions served by the more patent airways resulting in a greater degree of non-uniform ventilation.

This project was completed by Honours student Mei Ming Chan. She received a 1st class Honours and the Thoracic Society of Australia and New Zealand Young Investigator Award at the annual scientific meeting in Tasmania.

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Team Members

  • Professor Haydn Walters (Senior Member)