[Recent progress and future prospect of the prolonged extracorporeal lung assist for respiratory failure]

Extracorporeal membrane oxygenation (ECMO) is becoming an accepted therapeutic option for acute respiratory failure in both infants and adults. ECMO has been applied for relatively short-term support and numerous centers have reported satisfactory results with emphasis on patient selection, techniques of cannulation and perfusion, and prevention of complications. To use ECMO for a prolonged support, however, new type of artificial lung and system need to be developed. Most of the membrane oxygenators have the possibility of serum leakage through micropores. To prevent this problem, several dense membrane oxygenators have been developed and clinically used with good gas exchange. A low heparin dosage during ECMO results in reduced bleeding complication. Full systemic heparinization can be avoided during ECMO by using heparin-coated perfusion equipment. Respiratory support by means of pumpless PA-LA extracorporeal membrane oxygenation driven by pulmonary arterial pressure is attractive because of its simplicity and might be suitable for prolonged use. Further studies are necessary to develop an oxygenator for long-term ECMO.