Objective To investigate the prognostic significanceof early lactate clearance rate for severe acute respiratory failure patients on extracorporeal membrane oxygenation(ECMO).Methods Forty-three patients with severe acute respiratory failure supported by venous-venous(v-v)ECMO were enrolled from January 2007 to January 2013.Arterial blood lactate at pre-ECMO support(0 h)and at Objective To investigate the prognostic significance of early lactate clearance rate for severe acute respiratory failure patients on extracorporeal membrane oxygenation (ECMO). Methods Forty-three patients with severe acute respiratory failure supported by venous-venous (vv) ECMO were enrolled from January 2007 to January 2013.Arterial blood lactate at pre-ECMO support (0 h) and at