Design and Construction of a Mock Human Circulatory System

INTRODUCTION Congestive heart failure (CHF) contributes to more than 300,000 deaths every year in the United States [1]. CHF is a condition that causes the heart to inadequately distribute blood to the rest of the body, resulting in heart failure, poor perfusion, and ultimately, multisystem organ failure. Approximately 70,000 patients may benefit from a heart transplant, however, with only 2000 hearts available, patients must seek other alternatives [1]. Patients can improve their quality of life with support from a left ventricular assist device (LVAD). In order to comply with current FDA requirements, prior to in vivo testing in animal models, there must be a way to test LVADs and assure a functioning, reliable assist device in vitro, in an experimental flow loop. Models for circulation are becoming more popular and set the standard for testing pumps while varying hemodynamic parameters. Circulatory loop models must accurately represent important parameters in the human circulatory system under dynamic conditions. The American Society for Artificial Internal Organs (ASAIO) and the Society of Thoracic Surgeons (STS) suggest variables to be accounted for in a circulatory model [2]. Required testing also includes worst-case physiologic conditions. The purpose of this paper is to describe the construction of a mock circulatory loop and explain results obtained from preliminary in vitro testing with a centrifugal flow pump.