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

Source abstract

Abstract 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.