Characterization of an In Vitro Model of Extracorporeal Circulation: A New Tool for Investigating the Pathophysiological and Therapeutic Strategies in Whole Blood

Abstract

A clinically relevant extracorporeal circulation model would be a valuable tool for investigating the pathophysiological and therapeutic strategies in whole blood. Previous models were limited by issues such as large circuit area; the inability to achieve full bypass; and donor blood requirement for prime. Here we established a miniature circuit to overcome these limitations consisting of a peristaltic pump, a test cell, a blood reservoir, and an oxygenator connected via polyvinylchloride and porous platinum silicon tubing. A heparinised (10 U/mL) saline solution at pH 7.4 was used to prime the circuit and the test cell was incubated in a water bath to maintain the temperature at 37°C. Blood flow through the circuit was at 5 mL/minute rate. Haemodynamics, haemoglobin concentration, and blood gases were analysed and the circuit performance was optimised according to the levels of haemolysis at three circulation time intervals: before the start, 30 minutes, and 60 minutes. No statistically significant haemodynamics and blood gases differences were observed. We have established a miniature extracorporeal circuit consisting of asanguineous prime for CPB model that maintains clinically acceptable results regarding hemodynamic parameters, blood gases, and haemodilution. This surrogate model would be important for further use in clinically pertinent research.