DEVELOPMENT AND INITIAL IN-VIVO TESTING OF A NEW HYDRAULIC DRIVE SYSTEM (PAEDIPUMP) FOR CIRCULATORY SUPPORT IN INFANTS

The main limitation in the use of circulatory support in children is t he lack of an adequate system with regard to size and pumping capacity . Recently two pneumatically driven ventricular support systems with l ow volume chambers for use in a pediatric population became available. We have developed a hydraulic drive system with an advantageous exact control of the stroke volume. The system enables two different modes of operation: the full-empty and the filled-empty modes. in both cases the ventricle is empty at the end of systole. This new system was tes ted in experimental animals (6 pigs, body weight 9.5-14.0 kg) with nor mal and reduced left ventricular function (MAP<45 mmHg). A 25 ml ventr icle (HIA-Medos) was implanted The full-empty and the filled-empty mod e used led to a significant load reduction, both in animals with norma l and impaired cardiac function. Plasma lactate levels, pH-values and fetal body O-2-consumption were in the normal range during circulatory support indicating adequate organ perfusion. Results showed that suff icient ventricular support was achieved during all pumping modes due t o the possibility of controlling and modifying the stroke volume of th e hydraulically driven support system employed according to necessity This is a promising feature for ifs future application in infants with congenital or acquired heart diseases.