Investigation Of Interfacial Instabilities In Compliant Airway Models
Acute respiratory distress syndrome (ARDS) is a pulmonary disease caused by surfactant dysfunction as a result of various types of trauma including sepsis and smoke inhalation. ARDS has a mortality rate of ~40% and affects ~150,000 people in the United States annually. Mechanical ventilation is a necessary life sustaining therapy to reopen collapsed airways. However, without a sufficient amount of active surfactant, the pressure required to reopen the airway increases significantly. Unfortunately, conventional ventilation, while necessary, can cause ventilator-induced lung injury. Atelectrauma is a type of lung injury that occurs at low volumes, and involves a repeated recruitment and de-recruitment (RecDer) of lung airways that induces mechanical stress on the epithelial lining. Our goal is to elucidate the fluid mechanics of RecDer in compliant airway models designed to mimic pulmonary airways. Here we design and build an apparatus that allows us to evaluate airway model compliance. Secondly, we characterize “tube laws” of these compliant airway models using this apparatus and identify suitable lab-manufactured airway models for experimentation. Finally, we investigate the RecDer phenomena in these models by measuring the frequency of de-recruitment as a result of the change in tube angle orientation and find a maximum frequency associated with angle orientation and reopening velocity. This research may provide a starting point for investigating further implications of RecDer, both mechanically and biologically, as well as developing novel ventilation waveforms to improve outcomes in ARDS patients.