What are the odds of coming off ECMO?

Good day, I understand that the ECMO machine can be a life-saving technology for those with severe respiratory or cardiac failure. However, I'm curious to know, when a patient is undergoing ECMO treatment, what are the odds of them successfully coming off the machine and recovering from their condition? Are there any factors that significantly influence these odds, such as the severity of the initial illness or the patient's overall health?