Experimental Validation of an Extended Kalman Filter for Retained Fluid Volume Estimation in Peritoneal Perfusion Applications

This paper is motivated by peritoneal perfusion: the circulation of fluid through the abdomen of a patient or laboratory animal. Peritoneal perfusion applications include dialysis, drug delivery, and potentially providing supplemental oxygen to patients with respiratory failure. If an excessive fluid volume is retained in the abdomen during perfusion, medical complications, such as intra-abdominal hypertension and abdominal compartment syndrome, may arise. Previous work by the authors presents a state-space model of the abdominal cavity pressure dynamics causing such complications and proposes an extended Kalman filter (EKF) that uses these dynamics for retained volume estimation. In this paper, the authors aim to validate the EKF's performance using data from clinical experiments on two Yorkshire swine, which are different from the animal originally used for system identification and EKF design. In both experiments, the EKF runs online as perfusion takes place. The EKF-based volume estimate is then compared to a weight sensor-based estimate of the total fluid supplied to the animal plus the tubing connected to the animal. The two volume estimates correlate linearly, with an encouraging coefficient of determination of 91.6% for both animal experiments.