Week long partial pulmonary bypass with an artificial lung pumped by the right ventricle

Extracorporeal pumping PA-LA perfusions were carried out for 24 hrs in 5 awake, alert lambs by cannulating the main PA and the LA with large bore polyurethane cannulae. A mean of 42% of the basal cardiac was pumped through the membrane lung. When the PA occluder cuff was progressively inflated, up to 80% of the basal cardiac output was diverted to the extracorporeal circuit for short periods. Hemothorax remained a significant problem. Three lambs were electively perfused 12 hrs, 36 hrs, and 8 days without a roller pump, using a low resistance spiral coil membrane lung pumped by the RV. By inflating the occluder cuff, a mean of 55% of basal cardiac output was pumped by the RV through the membrane lung. The 8 day bypass lamb remained healthy and active without any bleeding or gross pathology. We did not observe air emboli, thromboemboli or gross infections in either group. We believe that such a mode of cannulation will eventually allow long-term perfusion of a low resistance membrane oxygenator driven directly by the RV.