In-Vitro and Predicted In-Vivo Performances of a Pneumatically Regulated Artificial Ventricle

Abstract

An all-pneumatic driving system is presented which provides close duplication of the Starling’s cardiac regulation function to an artificial left ventricle in mock circulation. The system, built from commercially available fluid operated devices, uses atrial pressure feedback to adjust the ventricle pumping air pressure, with the aid of a hydraulic/pneumatic pressure transducer developed especially for the application. A simple linear mathematical model for the physiological circulatory system is used to compare the simulated in-vivo performance of the system with Starling’s response of the natural left heart for different systemic resistances and compliances. The model is valid for output flows from 1 to 10 l/min and atrial pressure from 1 to 8 mmHg. It shows close agreement in ventricle output, arterial and atrial pressure changes between the artificial ventricle and the natural left heart for systemic resistance changes from about 5 × 104 to 5 × 105 kN-s/m5 and for typical venous to arterial compliance ratios of 24 to 37.