DESIGN AND PERFORMANCE OF A PHYSIOLOGICAL PULSATILE FLOW NEONATE-INFANT CARDIOPULMONARY BYPASS SYSTEM

The authors have designed an alternative infant cardiopulmonary bypass (CPB) system using the University of Texas neonatal pulsatile pump, w hich produces physiologic pulsatile flow and allows a low priming volu me. This system has been tested with normothermic CPB (n = 8), and dee p hypothermic circulatory arrest (n = 14) in 3 kg piglets. Data obtain ed during these studies suggest that this system can produce flow char acteristics that approximate normal physiologic values. Unlike other p ulsatile pumps, this pump can produce a very small stroke volume, rang ing 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 s ystem is designed to cause minimal hemodilution and minimal exposure o f blood to foreign surface areas. The pump does not produce negative p ressure, 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 w ith this system using a 10 Fr aortic cannula in 3 kg piglets; and seco nd, that a significant reduction in priming volume and hemodilution ca n be obtained using this system.