Time dependence of recruitment and derecruitment in the lung: a theoretical model

Jason H. T. Bates, Charles G. Irvin
2002 Journal of applied physiology  
Bates, Jason H. T., and Charles G. Irvin. Time dependence of recruitment and derecruitment in the lung: a theoretical model. Recruitment and derecruitment (R/D) of air spaces within the lung is greatly enhanced in lung injury and is thought to be responsible for exacerbating injury during mechanical ventilation. There is evidence to suggest that R/D is a timedependent phenomenon. We have developed a computer model of the lung consisting of a parallel arrangement of airways and alveolar units.
more » ... d alveolar units. Each airway has a critical pressure (Pcrit) above which it tends to open and below which it tends to close but at a rate determined by how far pressure is from Pcrit. With an appropriate distribution of Pcrit and R/D velocity characteristics, the model able to produce realistic first and second pressure-volume curves of a lung inflated from an initially degassed state. The model also predicts that lung elastance will increase transiently after a deep inflation to a degree that increases as lung volume decreases and as the lung becomes injured. We conclude that our model captures the time-dependent mechanical behavior of the lung due to gradual R/D of lung units.
doi:10.1152/japplphysiol.01274.2001 pmid:12133882 fatcat:eqvrxiabnnb7jo3qot3t4vr3qi