Does anyone know how this is handled in the USA , Canada and Europe?
Short answer - it isn't.
Longer answer:
Europe - all air ambulance flights are flown by professional crews (unless repatriating, mostly helos, the distances to the nearest hospital A&E aren't great enough)
USA - there is something similar, but
AFAIK again flown by professional crews (it's mainly biz jet owners donating time in their aircraft)
Canada - no idea