INTRATHORACIC AND INTRAABDOMINAL WALL IMPLANTATION OF A CENTRIFUGAL BLOOD PUMP FOR CIRCULATORY ASSIST

An implantable centrifugal pump (ICP) 320 mi in volume and 830 g in we ight has been developed for prolonged circulatory assist. The antithro mbogenicity of the ICP is provided by a balancing hole in the center o f the impeller. The watertightness and histocompatibility of the ICP a re supported by its silicone ring seal and its casing of titanium and acrylic resin, respectively. The total efficiency of the ICP was 30% a t a 5 L/min flow rate and a 100 mm Hg head. The heat generation, water tightness, and anatomical fitting of the ICP were assessed in an intra thoracic implantation in a goat (66 kg) and in an intraabdominal wall implantation in a goat (70 kg). Warfarin was given for anticoagulation in each experiment to keep the prothrombin time around 1.7 times that of the control. The temperatures of the pump surface, the pleura, and the room were measured every 3 h. Anatomical fitting was evaluated by pathological observation after the termination of the experiment. The ICP could run for 40 days in the chest cavity and for :il days in the abdominal wall. The temperature of the motor remained about 1.8 degre es C higher than the reference in both experiments. The ICP was comple tely covered by a layer of smooth fibrous tissue. The moisture content of the seals remained normal. Although a small amount of atelectasis was found in the lingula, neither lung adhesion nor necrotic change of the chest wall was observed. The inflammation of the surrounding tiss ue including foreign body reaction and thermal burn was minimal. In co nclusion, the ICP has satisfied in vivo testing of its watertightness, exothermicity, and anatomical fitting.