The Aachen MiniHLM - A Miniaturized Heart Lung Machine for Neonates with Congenital Heart Defect

摘要

Predominantly standard adult Heart Lung Machines (HLMs) are used for pediatric cardiac surgery, only with individually downsized components. Downsizing is limited, e.g. by the required gas exchange surface, etc. In order to diminish complications we developed a new miniaturized heart lung machine (Aachen MiniHLM) for neonates, with significantly reduced priming volume and blood contact surface by integration of all major system components in one single device. In particular, the MiniHLM is a Heart-Lung-Machine with the rotary blood pump centrically integrated into the oxygenator and the cardiotomy reservoir with integrated heat exchanger is directly connected. Thus, tubing is only necessary between patient and MiniHLM. In 2007 we first introduced this new concept of the Aachen MiniHLM [1], After a first animal test series several design optimizations appeared to be necessary. These design optimizations resulted in a highly integrated system with 102 ml priming volume (incl. arterial filter and a/v line) and reduced blood contact surface. To validate the over all concept and the design optimizations we conducted several in vitro and in vivo test series. These tests confirm the concept of the MiniHLM. Its low priming volume and blood contact surface may significantly reduce known complications related to cardiopulmonary bypass in neonates (e. g. inflammatory reaction and capillary leak syndrome).