Quantifying recirculation in extracorporeal membrane oxygenation: a new technique validated.

Rationale: The efficacy of veno-venous extracorporeal membrane oxygenation is limited by the phenomenon of recirculation, which is difficult to quantify. Existing measurement techniques using readily available equipment are unsatisfactory.

Objectives: 1) To compare the accuracy of measurements of recirculation made using equations comparing blood oxygen content or saturation alone at different points in an ex vivo circuit; 2) to validate a new step-change technique for quantifying recirculation in vivo.