Compact intra- and extracorporeal oxygenator developments

For patients with acute lung failure, mechanical ventila-tion entails the risk of lung tissue damage due to high oxygen pressure and concentration. Membrane oxygena-tion for one to two weeks can rest the lungs due to decreased ventilation parameters, representing a poten-tial bridge to recovery, but implies the substantial risks of blood damage, plasma leakage and infection, which often have fatal results for patients. At the Helmholtz Institute in Aachen, two types of membrane oxygenators, which aim to overcome previous limits, are under development. Both present compact designs, reduced surface and priming volumes and easier handling. HEXMO is a miniaturized extracorporeal membrane oxygenator. The integration of a small rotary blood pump into the centre of the oxygenator reduces the amount of tubing and connectors in the system. Blood is convec-tively warmed by the pump motor housing, thus, the use of a heat-exchanger can be avoided. This compact design reduces surface and priming volume and allows better handling, especially in critical situations. A second development is the intravascular oxygenator HIMOX, which is inserted directly into the vena cava. Priming volume and blood contact surface are reduced, as well as infection risk and control needs for the patient. A new cross-flow fibre configuration is used for improv-ing gas transfer within the limited space inside the vena cava. A microaxial blood pump is integrated into the device for compensating the pressure drop across the fibres and allowing venous return and physiological pressure in the organs proximal to the oxygenator. Perfu-sion (2004) 19, 251/255