The Oxygenation of Blood in Artificial Membrane Devices

The use of an extracorporeal “heart-lung machine” system to replace heart and lung function in a surgical patient is anincreasingly common event in medicine today. The most widely-used gas exchange devices (artificial lungs) in the heart-lung systems are still of the type that contact the blood directly with the gas phase, even though it is well known that prolonged exposure of blood to this high-energy interface causes toxic degradation (8, 30, 37) resulting in an unusually high mortality rate for procedures longer than a few hours duration. Presumably the reason for the continued use of gas contact devices is that rapid surgical procedures have been developed and taking into account factors such as reliability, cost, and convenience, surgeons find the gas contact devices to be adequate. For the long term support of a patient, however, it is agreed that direct gas contact devices cannot be used (15, 25, 29, 37).