Mathematical modelling of oxygenation under veno-venous ECMO configuration using either a femoral or a bicaval drainage

BACKGROUND: The bicaval drainage under veno-venous extracorporeal membrane oxygenation (VV ECMO) was compared in present experimental study to the inferior caval drainage in terms of systemic oxygenation. METHOD: Two mathematical models were built to simulate the inferior vena cava-to-right atrium (IVC → RA) route and the bicaval drainage-to-right atrium return (IVC + SVC → RA) route using the following parameters: cardiac output (Q(C)), IVC flow/Q(C) ratio, venous oxygen saturation, extracorporeal pump flow (Q(EC)), and pulmonary shunt (PULM-Shunt) to obtain pulmonary artery oxygen saturation (S(PA)O(2)) and systemic blood oxygen saturation (SaO(2)). RESULTS: With the IVC → RA route, S(PA)O(2) and SaO(2) increased linearly with Q(EC)/Q(C) until the threshold of the IVC flow/Q(C) ratio, beyond which the increase in S(PA)O(2) reached a plateau. With the IVC + SVC → RA route, S(PA)O(2) and SaO(2) increased linearly with Q(EC)/Q(C) until 100% with Q(EC)/Q(C) = 1. The difference in required Q(EC)/Q(C) between the two routes was all the higher as SaO(2) target or PULM-Shunt were high, and occurred all the earlier as PULM-Shunt were high. The required Q(EC) between the two routes could differ from 1.0 L/min (Q(C) = 5 L/min) to 1.5 L/min (Q(C) = 8 L/min) for SaO(2) target = 90%. Corresponding differences of Q(EC) for SaO(2) target = 94% were 4.7 L/min and 7.9 L/min, respectively. CONCLUSION: Bicaval drainage under ECMO via the IVC + SVC → RA route gave a superior systemic oxygenation performance when both Q(EC)/Q(C) and pulmonary shunt were high. The VV-V ECMO configuration (IVC + SVC → RA route) might be an attractive rescue strategy in case of refractory hypoxaemia under VV ECMO. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40635-022-00434-x.