Gas exchange across native lungs and extracorporeal membrane in neonates and pigs during extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a commonly used treatment modality for severe neonatal respiratory failure. The aim of the present study was to evaluate the relationship between ECMO blood flow and gas exchange across the native lungs and the extracorporeal membrane. In three healthy pigs, the ECMO flow correlated significantly with oxygen transfer (VO2) across the membrane (n = 12, r = .90, P < .001) and inversely with VO2 across the lungs (n = 12, r = -.75, p < .005). In three pigs with acute respiratory distress syndrome induced by repeated bronchoalveolar lavage, flow also significantly correlated with VO2 across the membrane (n = 9, r = .93, P < .001) and inversely with VO2 across the lungs (n = 9, r = -.97, P < .001). Eight neonates had measurements taken at different time intervals and different flow rates during ECMO. The ECMO flow correlated significantly with VO2 across the membrane (n = 45, r = .61, P < .001) and inversely with VO2 across the lungs (n = 15, r = -.54, P < .05). The relationship between carbon dioxide transfer (VCO2) and ECMO flow rates had the same trend as VO2 on all occasions. It is concluded that the ECMO flow rate is one of the main determinants of gas exchange across the lungs and the membrane.