Is ECMO covered by insurance?

Could you please clarify for me whether or not ECMO, or extracorporeal membrane oxygenation, is typically covered by health insurance policies? I understand that it's a highly specialized and potentially costly procedure, so I'm wondering if it's generally considered a covered service under most insurance plans. I'm hoping to get a better understanding of the financial implications associated with this type of treatment in the event that it may be necessary for a loved one or myself in the future.