To temporarily replace the heart’s and lungs’ gas exchange capabilities, extracorporeal membrane oxygenation is used. Rather than mending damaged organs, this technology uses a technique called extracorporeal membrane oxygenation to carry out the mechanical functions of the organs outside of the body. The device forms an uninterrupted circuit that reroutes blood, filters out carbon dioxide, replenishes oxygen levels, and then delivers the blood to the patient. Patients with life-threatening but treatable diseases can give their own cardiopulmonary systems a break with this bypass. This procedure’s function as a potent supportive intervention in critical care becomes clearer when one grasps its mechanical sequence.
Initiating the Circuit: Vascular Access and Blood Drainage
The process begins with vascular access, typically achieved by percutaneously placing large-bore cannulae into major veins or arteries. In Veno-Venous (VV) extracorporeal membrane oxygenation, used for respiratory failure, a drainage cannula in a central vein removes deoxygenated blood from the body. For cardiac failure requiring Veno-Arterial (VA) support, the configuration includes both venous drainage and arterial return. The blood moves from the patient into the circuit through these cannulas, driven by the patient’s own venous pressure or, in some systems, assisted by a small pre-pump. This marks the start of the blood’s journey outside the body.
The Core Phase: Pump-Driven Gas Exchange
Once in the circuit, the deoxygenated blood is propelled by a centrifugal pump. This pump generates a non-pulsatile flow, gently moving the blood without causing significant hemolysis. The blood then enters the namesake component: the membrane oxygenator. This device is the artificial lung, containing thousands of hollow fibers. Oxygen flows on one side of these fiber membranes, while the patient’s blood flows on the other. Gas exchange occurs by diffusion down concentration gradients; carbon dioxide moves out of the blood, and oxygen moves in. This precise control over gas levels is the defining action of extracorporeal membrane oxygenation.
Completing the Loop: Thermoregulation and Blood Return
After passing through the membrane oxygenator, the now oxygenated blood is warmed or cooled to a set temperature by an integrated heat exchanger. Precise temperature management is crucial for maintaining patient stability and metabolic rate. The blood is then returned to the patient. In VV configurations, it goes back into a central vein to circulate through the body. In VA configurations, it is returned directly into the arterial system, bypassing the heart and lungs entirely to provide both cardiac output and gas exchange. This creates a complete, life-sustaining loop that can be maintained for days or weeks.
The procedure of extracorporeal membrane oxygenation is a testament to biomedical engineering, replicating vital physiological functions through an external circuit. Its effectiveness relies on the seamless integration of multiple components to drain, pump, oxygenate, and return blood. At WEGO Medical, we view the precision required for this therapy as a guiding principle. Our commitment to developing and supplying high-fidelity medical technology is aligned with the exacting standards demanded by critical care applications such as extracorporeal membrane oxygenation.
