Miniature undulation pump for the study of renal circulation

Background: In order to investigate the concept of the distributed artificial heart (D-AH), the undulation pump with one-half scale model was designed for use as a renal artificial heart. Method: This pump can generate arbitrary flow pattern: continuous flow, pulsatile on continuous flow and complete pulsatile flow. The outer diameter, thickness and priming volume of the pump were 38 mm, 11 mm and 3.2 mL, respectively. The total size and weight of the constructed miniature undulation pump with motor was 38 mm in diameter, 32 mm in length and 67.5 g, respectively. The maximum output was 5 L min^-1 against 100 mmHg of pressure load in a mock circulation loop, using water as a fluid at 3600 rpm of the motor speed. We performed animal experiments with goats. The pump was connected between the left atrium and the left renal artery. Results: It was confirmed that the pump performed well enough as a renal artificial heart and could generate an arbitrary flow pattern and a blood flow rate greater than control flow. Discussion: The miniature undulation pump is suitable for studying the renal circulatory physiology. The most difficult task in the animal experiment was connecting the pump output cannula to the renal artery. We are planning to develop a new cannula and to perform a chronic animal experiment on kidney perfusion in the goat.