Why do patients get ECMO?

Could you explain the reasons behind why patients might require ECMO treatment? Are there specific medical conditions or emergencies that typically necessitate the use of ECMO? Additionally, what are the benefits of ECMO for patients with severe respiratory or cardiac failure, and how does it help support their vital organ functions? Lastly, are there any potential risks or complications associated with ECMO therapy that patients and their families should be aware of?