Fig. 1.

Ventilator days before starting ECMO and survival rate. The majority of patients were changed to ECMO after 2–3 ventilator days; however, some patients were changed to ECMO after a longer period of ventilatory management. The survival rate decreased gradually in accordance with a higher number of ventilator days before starting ECMO. The gray bars indicate the numbers of survivors, the black bars indicate the numbers of deaths, and the white circles indicate the survival rates. ECMO, extracorporeal membrane oxygenation