Oxygenator

An oxygenator is a medical device used to supplement or replace the oxygen exchange function of the lungs. It removes carbon dioxide from blood and adds oxygen by passing the blood across a semipermeable membrane or through a series of gas-permeable surfaces. Oxygenators are employed during cardiothoracic surgery, in extracorporeal membrane oxygenation (ECMO) circuits, and in various intensive care situations where the patient's lungs are unable to maintain adequate gas exchange.

The first practical blood oxygenator was developed during the 1930s and 1940s. Early models were large and primed with air, but advances in polymer science and membrane design during the 1960s and 1970s led to smaller, more efficient devices. Modern oxygenators use hollow-fiber or sheet-membrane technology, allowing high gas transfer rates while minimizing hemolysis or clotting risks.

Oxygenators are classified by the patient circuit they support. Veno-venous (VV) oxygenators provide respiratory support for patients with intact hearts, while veno-arterial (VA) oxygenators also deliver circulatory support for those with cardiac failure. In cardiopulmonary bypass, oxygenators temporarily replace lung function during open heart surgery. ECMO oxygenators have become critical in treating severe acute respiratory distress syndrome, postoperative pulmonary failure, and as a bridge to lung transplantation or recovery.

Key design goals include low priming volume, low resistance to blood flow, and high oxygen transfer efficiency. Complications can arise from clot formation, hemolysis, membrane failure, or gas embolism. Continuous monitoring of pressures, dissolved gases, and filter integrity is essential for safe operation. Research continues toward developing smaller, less thrombogenic membranes and integrating sensors for real-time gas exchange monitoring, which would improve both patient safety and device performance.