Recirculation in venovenous extracorporeal membrane oxygenation.

Recirculation, a phenomenon in which reinfused oxygenated blood is withdrawn by the drainage cannula without passing through the systemic circulation, decreases the efficiency with which venovenous extracorporeal membrane oxygenation (ECMO) provides oxygenation. The precise amount of recirculation may be difficult to quantify. However, interventions should be attempted to reduce recirculation when oxygen delivery is suboptimal and recirculation is suspected. Several techniques, including the use of dual-lumen cannulae, have been successful in minimizing recirculation in venovenous ECMO. This article will provide an overview of the factors that affect recirculation, methods that may be used to quantify recirculation, and interventions that may reduce recirculation, thereby increasing ECMO efficiency.