Cardiac output (CO) monitoring is important in patient connected to extracorporeal membrane oxygenation (ECMO) either Veno-Venous (VV) ECMO or veno- arterial (VA) ECMO - In VV ECMO patient's adequate oxygenation is achieved with ECMO flow above 60 % of cardiac output and in VA ECMO patients adequate hemodynamic is maintained with ECMO flow 50-70 ml / kg/min.