A Numerical Analysis of Mechanical Ventilation in Newborns

Background: Mechanical ventilation can be lifesaving procedure but has also been associated with lung injury. In order to better understand the application mechanical ventilation to newborns a numerical study has been performed based on a physiological/physical model. The model consists of the time integration of a quasi-static engineering pressure loss approach to simulate dynamic respiratory parameters during pressure control mode mechanical ventilation. The effects of pressure target, inhalation:exhalation ratio, lung compliance, and endotracheal tube (ETT) size on peak inspiratory and expiratory flow rates, tidal volume and tidal volume retained at the end of exhalation are determined. Also simulations of an ETT obstruction and a comparison of pressure to volume control mode are performed. In an appendix in vivo measurements and the results of a numerical analysis of the effects of fluid property variation on dynamic ventilation parameters in pressure control mode during xenon anesthesia are compared, thus providing a validation of the numerical method. The in vivo measurements were taken prior to surgery during the wash-in phase of xenon anesthesia in adults. This in silico study provides quantitative insight to mechanical ventilation of newborns, a vulnerable patient group where in vivo data are often difficult to obtain.