In the US and probably the rest of the English speaking countries, typically only medical professionals and first responders are required to render aid, but the law does protect "good samaritans" from legal culpability if they do help.
From a actual lawsuit: Someone without the proper training started an IV which later caused sepsis and death. Since the patient was admitted to an hospital it was not clear if an improply placed IV caused the death or an improper care in the hospital.
In nearly all the situations the staff in the building told the sick people outside to call 911 to get transported inside two feet inside the door.
The hospital workers and by that I mean nurses and doctors were unwilling to help even though the people outside were very ill.
I ask because I once walked my relative into an ER and they were attended to, no problem.
I can understand some concerns of staff but to flat out refuse seems to go against the ethics of being in the medical trade.
I also suspect it's government bureaucracy and union rules, paperwork trumps life I guess.
http://www.cbc.ca/news/health/hospital-er-call-help-1.368630...
Even if you are a paramedic with the local fire department, in uniform and walking down the street, unless you are on-duty, you do not have to act. You'd be a massive dick if you didn't, but there is no legal requirement.