Perioperative management of calves undergoing implantation of a left ventricular assist device

Objective-To describe perioperative management of calves that underwent lef t lateral thoracotomy, aortic cross-clamping, partial left heart bypass and implantation of a left ventricular assist device. Sample Population-A total of 43 healthy castrated male calves, weighing 121 +/- 24 kg. Results-Diazepam (mean +/- SD, 0.26 +/- 0.07 mg/kg), ketamine (5.9 +/- 2.17 mg/kg) and isoflurane were used in the anesthetic management of calves und ergoing implantation of a left ventricular assist device in the descending thoracic aorta. Other adjunctive agents administered were fentanyl (11 +/- 5.4 mu g/kg), lidocaine (4.9 +/- 3.19 mg/kg), bupivacaine (0.75%) and butor phanol (0.49 +/- 0.13 mg/kg). None of the calves regurgitated at induction or during intubation. A tube was used to drain the rumen and prevent bloat during the procedure, Partial left heart bypass was used to perfuse the caudal half of the body d uring the period of aortic cross clamp and device implantation. Initial mea n systemic blood pressure was 96 +/- 25 mm Hg, and pressures measured in th e auricular artery increased during aortic cross-clamping and bypass. Vasoc onstrictor therapy was required to treat caudal arterial hypotension during the procedure in 9 calves. Mean systemic arterial pressures returned to ba seline values by the end of the anesthetic period. Initial mean pulmonary a rterial pressures (PAP) were 22 +/- 3 mm Hg. A significant but transient in crease in pulmonary arterial pressure occurred after both heparin and prota mine administration. Conclusions-The described anesthetic protocol was effective for thoracotomy and implantation of an intra-aortic left ventricular assist device in norm al calves. Partial left ventricular bypass was a useful adjunct during the period of aortic cross clamp. The doses of heparin and protamine administer ed were effective. Responsibility to monitor oxygenation of the cranial hal f of the animal continues during the bypass period as hypoxemia due to pulm onary dysfunction will not be detected by the perfusionist. (C)Copyright 20 00 by The American College of Veterinary Surgeons.