IN-VIVO EVALUATION OF AN EXTRACORPOREAL PEDIATRIC CENTRIFUGAL BLOOD PUMP

This paper summarizes the authors' in vivo experience in evaluating a miniature centrifugal blood pump designed for pediatric/neonatal ventr icular support. Left ventricular bypass was accomplished in two adult sheep and five juvenile lambs (5.5-80.0 kg) via either central (left v entricle to carotid artery) or peripheral (jugular vein to carotid art ery) cannulation. Animals were weaned from mechanical ventilation and continuously monitored. Hemodynamic parameters remained within a norma l range over the duration of the bypass. Two of five lambs were electi vely killed at 8, and 76 hours; the remaining three lambs died from re spiratory complications at 33, 44, and 156 hours. There were no mechan ical complications, and blood seal integrity was confirmed beyond 6 da ys. The pump speed was maintained at 3,000-4,500 rpm with pump flow ra tes between 0.4-1.5 L/min. Average plasma free hemoglobin was below 20 mg/dl in the five lamb experiments. Renal, hepatic, and hematologic i ndices also remained within physiologic ranges. Histopathologic analys es of major organs revealed renal cortical infarctions in two of five lambs. Examination of the pump surfaces after explant indicated small areas of thrombus in the housing adjacent to the outflow ports in two experiments. These encouraging results support further testing and ref inement of this miniature centrifugal pump.