Can Side Holes in Returning Cannula Improve VV-ECMO Effectiveness?

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is a life-saving therapy used for patients with respiratory failure; however, its effectiveness may be compromised by high recirculation rates. Recirculation occurs when oxygenated blood from the returning cannula is drawn back into the ECMO circuit by the drainage cannula. In this study, we compared the recirculation rates between a returning cannula with 2 and 12 side holes for ECMO flow of 4 L/min using computational modeling of blood flow and oxygen diffusion. Simulations were computed using a patient-specific model of the right atrium, superior and inferior vena cava derived from the CT scan. For both cannulas, the recirculation rate was 12% and oxygen saturation was 86%, suggesting negligible influence of side holes on VV-ECMO efficacy. Further studies are needed to assess whether different designs could improve VV-ECMO performance. The pipeline used here can be used to evaluate and optimize such designs.