Early in vivo Evaluation of Ventricular Assistance with a Miniature Centrifugal Blood Pump (TinyPump) in Rabbits

We have developed an ultraminiature centrifugal pump, TinyPump, with a priming volume of 5 ml. The in vivo performance of TinyPump was compared with that of HPM-05 for left ventricular support. Each pump group included seven rabbits weighing 3.4–3.8 kg. One rabbit in the TinyPump group and two rabbits in the HPM-05 group died of unsuccessful cannulation. The remaining rabbits (six in the TinyPump group and five in the HPM-05 group) were instrumented and observed for 240 minutes. The pump flow was maintained at around 200 ml/min. The priming volumes of the entire circuits were 25 and 45 ml for TinyPump and HPM-05, respectively. TinyPump required a higher rotation speed (2214 ± 47 vs. 1261 ± 87 rpm, p