Modeling and Experimental Identification of Peritoneal Cavity Pressure Dynamics during Oxygenated Perfluorocarbon Perfusion

This paper examines the problem of modeling the dynamics of the filling, drainage, and pressurization of the peritoneal cavity of a laboratory animal during perfusion. The paper is motivated by the potential of the peritoneal perfusion of an oxygenated perfluorocarbon (PFC) to provide a pathway for gas exchange in patients suffering from respiratory failure. Modeling cavity mechanics is important for avoiding excessive intracavity pressures that could potentially cause abdominal compartment syndrome during perfusion. Previous research in the literature examines elastic cavity behavior, but the problem of experimentally identifying models that couple this behavior with suction-assisted discharge remains relatively unexplored. Towards this goal, we performed large animal (namely, swine) experiments where we measured variables including peritoneal intracavity pressure, suction pressure, and PFC inflow. A simple state-space model fits data from the above experiment well. This model helps elucidate important preliminary insights into: (i) the role of active suction in facilitating discharge, (ii) the stiffening of the peritoneal cavity with perfusion, (iii) the linearity of cavity discharge behavior, (iv) the potential need to examine the impact of paralytics on cavity pressure dynamics as future work.