Currently, the main risks of traditional ECMO-therapy are blood loss, high risk of infection and substantial hemolysis. These are particularly due to large blood contact surfaces and shear stress resulting from complex systems. A new system for extracorporeal lung assist is presently being developed at the Institute of Applied Medical Engineering, Helmholtz-Institute Aachen. A rotating bundle of membrane fibers performs the function of both gas exchange and blood delivery. The pump-lung rotates by means of a gas-driven turbine. The resulting device is transportable and stand-alone and is suitable for rescue applications.
The Highly Integrated Extracorporeal Rescue Oxygenation System (HEROS) is a pneumatically-driven pump-lung. Supplied by an integrated cartridge, gas provides for gas exchange and at the same time generates rotation of an implemented turbine. A hollow cylinder consisting of membrane fibers is powered by the turbine and generates centrifugal forces to deliver blood. Gas exchange is increased by intensive blood mixing between the fibers.
Preliminary HEROS prototypes provide blood flow of approximately 3 L/min and compensate for internal resistance. Turbine design was optimized with regard to the required power supply.
The gas exchange system and the driving system are multifunctional: the fibers effect gas exchange and blood delivery, while the gas delivery system effects gas exchange and pneumatic drive, resulting in a compact system configuration. The HEROS is independent of any external energy supply due to the integrated gas cartridge. Reduction of blood-conveying components guarantees less blood contact surface, and consequently maximizes biocompatibility. All items considered, the HEROS is a promising system for pediatric lung assist.