SUBCHRONIC USE OF THE ST-JUDE CENTRIFUGAL PUMP AS A MECHANICAL ASSISTDEVICE IN CALVES

The purpose of this experiment was to study the effects of the St, Jud e Lifestream centrifugal pump on hemodynamic and hematologic parameter s and the incidence of postmortem findings in a subchronic ex vivo lef t ventricular assist animal model. Five calves were implanted with the pump as a left ventricular assist device (left atrial to thoracic aor ta bypass) and studied for 96 h of continuous pumping under identical conditions. Heparin (100 IU/kg) was administered only in the initial s aline pump prime. Throughout the protocol, mean arterial and central v enous pressures averaged 102.1 +/- 4.6 and 3.4 +/- 2.2 mm Hg, respecti vely. Pump flow was 47.8 +/- 8.4 ml/kg/min at a mean pump speed of 1,6 76.3 +/- 106.1 rpm. No clinical abnormalities or mechanical malfunctio ns attributable to the pump were detected during the 96 h of continuou s pumping for each calf. Mean plasma-free hemoglobin after 96 h was 3. 9 +/- 3.7 mu mol/L (p = 0.337 compared to baseline). At post mortem, r enal infarctions were detected in 1 calf. No other pump-associated les ions were detected in any of the other calves. We have concluded that the St. Jude Lifestream centrifugal pump functions reliably during 96 h of continuous left heart bypass in a calf model.