RESUMO
BACKGROUND: Veno-venous extracorporeal membrane oxygenation has several advantages over veno-arterial support for patients with severe reversible respiratory failure. However, recirculation can limit oxygen delivery as pump flow increases. This could be ameliorated by placing the return catheter in the right ventricle instead of the central veins. We compared recirculation in veno-right ventricular support with that in conventional veno-venous support and its relationship with pump flow. METHODS: Five greyhound dogs were sequentially cannulated percutaneously for both veno-venous and veno-right ventricular support. Recirculation was measured by comparing oxygen levels in the circuit drainage and return lines before and immediately after a sudden increase in circuit oxygenation at pump flows between 0.5 L/min and 4 L/min for both modalities. RESULTS: Recirculation was reduced in veno-right ventricular support compared with conventional veno-venous support at 4 L/min pump flow (8.4% versus 37.9%, p=0.0076) and increased less with increases in pump flow (2.9% per 1 L/min vs. 11.1% per 1 L/min, p<0.0001). CONCLUSIONS: Recirculation can be dramatically reduced by returning blood into the right ventricle, which improves oxygen delivery to the lungs and the systemic circulation. The design of specialized catheters may facilitate percutaneous ventricular cannulation, improve safety and further reduce recirculation.
