The authors have designed an alternative infant cardiopulmonary bypass (CPB) system using the University of Texas neonatal pulsatile pump, which produces physiologic pulsatile flow and allows a low priming volume. This system has been tested with normothermic CPB (n = 8), and deep hypothermic circulatory arrest (n = 14) in 3 kg piglets. Data obtained during these studies suggest that this system can produce flow characteristics that approximate normal physiologic values. Unlike other pulsatile pumps, this pump can produce a very small stroke volume, ranging from 0.5 to 7.1 ml with a pump rate of 120 beats/min. These stroke volumes correspond to our target value of 1 ml/kg body weight. This system is designed to cause minimal hemodilution and minimal exposure of blood to foreign surface areas. The pump does not produce negative pressure, and therefore the venous reservoir is not essential, and only a cardiotomy reservoir is required. Conclusions after in vivo testing are, first, that physiologic pulsatile flow can be achieved readily with this system using a 10 Fr aortic cannula in 3 kg piglets; and second, that a significant reduction in priming volume and hemodilution can be obtained using this system.
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