Development of the oxygenator: past, present, and future.

From the 1950s to the 1980s, the most widely used oxygenator in the clinical field was the disposable bubble oxygenator. However, membrane oxygenators have become the preferred clinical choice over the years. In the United States, membrane oxygenators used in cardiopulmonary bypass operations account for the majority of clinical oxygenator use. Membrane oxygenators have an equal capability for oxygenating venous blood compared with other type of oxygenators such as the bubble type and film type; however, the membrane oxygenator requires a smaller volume for priming to achieve a sufficient gas transfer rate and results in less blood trauma such as hemolysis because it uses a similar mechanism to the natural lung. In the 1980s, the first capillary-type oxygenator adopted the system of intracapillary blood perfusion. However, this induced high pressure resistance in the module and caused hemolysis. Thus, at present, capillary oxygenators commonly adopt the system of extracapillary blood perfusion. Microporous hollow-fiber membranes are primarily used for short-term cardiopulmonary bypass application, whereas nonmicroporous hollow-fiber membranes are primarily used for long-term extracorporeal membrane oxgenation application.