MOCK CIRCULATORY SYSTEM FOR THE CONTINUOUS FLOW TOTAL ARTIFICIAL HEART

Abstract

Purpose: A mock circulatory loop was designed to be used as a platform for testing feedback control strategies for the continuous flow total artificial heart (TAH). Methods: The mock circuit comprises both systemic and pulmonary circulations. The TAH consists of 2 axial flow pumps. The atria are flexible and collapse under excessive negative pressure. Pulmonary and systemic vascular resistances are adjusted to approximately 4 and 20 Wood units, respectively, using tubing clamps. The respective compliances are modeled with sealed cylinders containing air. During normal operation, approximately 80% of the fluid volume is in the systemic circulation. Pressure signals are filtered with anti-aliasing filters. Aortic and pulmonary arterial pressures, left and right atrial pressures, and flow rates are sampled at 1 kHz. Results: A wide range of hemodynamic conditions were simulated. Baseline aortic and pulmonary arterial pressures were maintained at 80 and 20 mm Hg, respectively, while atrial pressures were kept at approximately 0 mm Hg. Flow rate in the left pump was slightly higher than in the right due to the bronchial shunt. The mock circuit was successfully used for testing physiologic feedback control strategies for the dual-pump system. Conclusions: Normal and pathologic conditions, including atrial collapse, can be readily simulated in the mock circuit, making it a suitable platform for testing feedback control algorithms aimed at correcting hemodynamic abnormalities in patients with TAHs.