Die Aachener MiniHLM - Eine miniaturisierte Herz-Lungen-Maschine für neugeborene mit angeborenem Herzfehler

The operation of congenital heart defects in neonates often requires the use of heart-lung machines (HLM) to provide perfusion and oxygenation. This is prevalently followed by serious complications i. a. caused by hemodilution and extrinsic blood contact surfaces. Thus, one goal of developing a HLM for neonates is the reduction of priming volume and contact surface. The currently available systems offer reasonable priming volumes for oxygenators, reservoirs, etc. Although, the necessary tubing system bears the highest volumes within the whole system. This is due to the use of roller pumps and the hence resulting placement of the complete HLM between 1 and 2 m away from the operation table and due to connective tubing between the components. Therefore, we persued a novel approach for a miniaturized HLM (MiniHLM) by integrating 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 heat exchanger integrated into the cardiotomy reservoir which is directly connected to the pump inlet. Thus, tubing is only necessary between patient and MiniHLM. A total priming volume of 104 ml (incl. arterial filter and a/v-line) could be achieved. To validate the overall concept and the specific design we conducted several in-vitro and in-vivo test series. All tests confirm the novel 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).