Extracorporeal life support

Once venous is blood is removed via the venous cannula, the ECLS pump (either a roller head pump or a centrifugal pump may be used) circulates blood forward to a semi-permeable membrane lung. In the membrane lung, gradient-related diffusion of gases, namely oxygen and carbon dioxide, occurs. Oxygen diffuses from the sweep gas being applied to the membrane into the blood; carbon dioxide diffuses from the blood into the sweep gas. The now-oxygen rich blood is warmed during its flow through a heater and infused into the aorta via the carotid artery cannula placed to provide venoarterial ECLS. In the case of venovenous ECLS, this oxygen-rich blood is infused into the right atrium via the infusion lumen of the double lumen venous cannula. During venoarterial ECLS, the central venous oxygen saturation can be continuously monitored by a fiber-optic catheter placed in the venous side of the circuit. (Provided and reproduced courtesy of the Extracorporeal Life Support Organization; contributed by Dr. Heidi J Steflik.)