Oxygéenateurs : évolution et nouveautés Oxygenators : evolution and update

Abstract

The ideal extracorporeal oxygenator transfers oxygen into and carbon dioxyde out of the body at physiologic blood flow rates without blood trauma and a small priming volume. Compared with natural lungs, artificial lungs have much smaller surface areas and are limited by diffusion. Despite improved oxygenators designs that offset these differences somewhat, the maximum oxygen transfer of even the most efficient artificial lungs is less than half that of normal lungs. Nevertheless the progress realized for 50 years allowed a considerable improvement of oxygenators. From more than two liters, the priming volumes reache now less than 200 ml of bloodless solutions.

The biocompatibility was recently improved by the complete suppression of the blood-air interface because of continuous polymethylpentene membranes employment with gaz transfers of 02 and C02 equal to those of the microporous polyethylene membranes. The coated surfaces by heparin, phosphorylcholine or cyclosiloxane decrease the cell and the non cell blood activation. The devices of deairing by trap and filter are optimized in the oxygenator, enhancing the safety . The miniaturization of the cardio pulmonary bypass circuits goes on with the incorporation of a centrifugal pump head in the design of the oxygenator.