In situ enhancement of pulmonary surfactant function using temporary flow reversal

Glindmeyer HW 4th, Smith BJ, Gaver DP 3rd. In situ enhancement of pulmonary surfactant function using temporary flow reversal. J Appl Physiol 112: 149-158, 2012. First published October 13, 2011; doi:10.1152/japplphysiol.00643.2011.-Acute respiratory distress syndrome is a pulmonary disease with a mortality rate of similar to 40% and 75,000 deaths annually in the United States. Mechanical ventilation restores airway patency and gas transport but leads to ventilator-induced lung injury. Furthermore, surfactant replacement therapy is ineffective due to surfactant delivery difficulties and deactivation by vascular proteins leaking into the airspace. Here, we demonstrated that surfactant function can be substantially improved (up to 50%) in situ in an in vitro pulmonary airway model using unconventional flows that incorporate a short-term retraction of the air-liquid interface, leading to a net decrease in cellular damage. Computational fluid dynamic simulations provided insights into this method and demonstrated the physicochemical hydrodynamic foundation for the improved surfactant microscale transport and mobility. This study may provide a starting point for developing novel ventilation waveforms to improve surfactant function in edematous airways.