The duration of extracorporeal circulation depends mainly on the duration of the cardiac surgery operation. Generally speaking, a cardiac operation will be completed within 3 hours of extracorporeal circulation, but for particularly complex operations, those with particularly poor preoperative cardiac function, or those where the operation does not proceed smoothly, the duration of extracorporeal circulation will be extended accordingly. Another factor that determines the duration of extracorporeal circulation is the duration of use of the membrane lung, which is currently commercially available with a guarantee of 6 hours, almost twice the duration of all extracorporeal circulation procedures. However, membrane lungs can malfunction, and if they do, then replacement will need to be suspended regardless of the duration of extracorporeal circulation. There is no maximum time for extracorporeal circulation. If it is not possible to evacuate extracorporeal circulation during a cardiac procedure, it is usually converted to ECMO and then returned to the ICU with the ECMO machine, which is a special form of extracorporeal circulation and the duration of ECMO is a continuation of the duration of extracorporeal circulation. The longest duration of extracorporeal circulation that the physician himself experienced was 630 minutes, or 10.5 hours, and because the patient was unable to evacuate the extracorporeal circulation, he was eventually converted to ECMO and returned to the ICU with the machine.