Development and initial testing of a pediatric centrifugal blood pump

We are developing a miniaturized centrifugal blood pump for use as a temporary cardiac assist device in neonatal and pediatric sized patients. This pump has a very low priming volume of 13 mL. A small motor stator has also been designed, which resulted in a device that can be placed very close to the patient, thereby minimizing overall circuit volume. Testing to date has included in vitro hemodynamic performance, in vitro hemolysis generation, and in vivo evaluation in 5 lambs weighing 5.5 to 21 kg. Two lambs underwent peripheral cannulation from external jugular vein to carotid artery, whereas 3 others were cannulated from left atrium to carotid artery. In vitro data demonstrated pump capacity spanning 0.3 to 3.0 L/min and very low hemolysis generation at these conditions. In vivo, the pump functioned satisfactorily for periods up to 148 hours, and the bypass appeared to be well tolerated by the animals. Plasma free hemoglobin levels remained less than 25 mg/dL during all animal experiments. All devices were thrombus-free at explantation. We conclude that this device has merit as an alternative to current oversized systems used for neonatal and pediatric cardiac assistance. In addition, a chronic neonatal lamb model in which to evaluate pediatric circulatory assist devices has been developed successfully.