A coma is an emergency medical condition. If you are with a person who develops signs and symptoms of a coma, call 911 or your local emergency number immediately. When you arrive at the hospital, emergency room staff will need as much information as possible from family and friends about what happened to the affected person before the coma.
https://www.mayoclinic.org/diseases-conditions/coma/diagnosis-treatment/drc-20371103

