The effect of high-frequency ventilation on non-Newtonian properties of bronchial mucus.

We have investigated the changes in the non-Newtonian properties of human bronchial mucus brought about by in vitro high frequency ventilation. This type of ventilation brought about changes in viscous properties, measured during creep and oscillation of the mucus, which would be expected to reduce mucus clearance in vivo. We suggest that any beneficial effects of clinical high-frequency ventilation on respiratory mucus clearance in patients are not brought about by long-term (more than a few seconds) changes in the viscous properties of the mucus itself.