[Development of a novel artificial heart-lung system for long-term cardiopulmonary support--experimental evaluation in goats with total cardiopulmonary bypass].

A novel cardiopulmonary support (CPS) system for long-term use was designed and evaluated. The CPS system consists of an air-driven ventricular assist device (VAD) and a newly developed compact membrane oxygenator (MO). The VAD had proven durable and antithrombogenic in over 200 clinical uses. The membrane oxygenator, with a membrane area of 1.2 m2 and priming volume of 140 ml, is compact and designed to be interposed in the VAD conduit. It is made with a special hollow fiber membrane, in which micropores are blind-ended so that serum leakage can be prevented during prolonged use. The blood contacting surface of the MO is heparinized with a newly developed covalent bonding technique that ensures good thrombus resistance. Chronic animal experiments of total CPS were carried out for up to 336 hr in seven goats weighing from 28 to 36 kg. Venoarterial bypass was instituted with the CPS system in which all venous blood was drawn from both the right atrium and ventricle and returned to the aorta. No systemic anticoagulant therapy was used, except for a heparin-added fluid infusion to keep the monitoring lines open. Blood flow rate ranged between 107 to 130 ml/kg/min, oxygen transfer between 142 to 174 ml/min, and carbon dioxide removal between 78 to 148 ml/min. No plasma leakage was observed at the hollow fiber membrane. Substantial changes were not found in platelet count or other coagulation factors. And no perceptible thromboembolism was found at necropsy in any case. These results indicate that the system is competent enough to be used for long-term CPS, such as a bridge to lung or heart-lung transplantation.