The filmmaker Dan Wooley went to Survivor-mode after being trapped under the tons of wreckage in the lobby of his hotel by the January 12 earthquake that hit Haiti.
Wooley used the technology at hand to assess his wounds, treat them as best he could and stay alive until rescue workers dug him out. He first opened his DSLR camera to light the wreckage and his surroundings. After finding a safe spot in an elevator shaft, he turned to his iPhone and one of his apps to treat himself - Pocket First Aid and CPR (iTunes link).
Suffering from a leg and head injury, Wooley used his clothes to make a tourniquet for his leg and stop the bleeding from his head wound. The app also instructed him not to fall asleep, so he set his iPhone's alarm to go off every 20 minutes.
He scribbled goodbye notes to his wife and children in a notebook and kept himself alive until a group of French rescue workers found him. He attributes his survival to divine providence.
Wooley was shooting a film about the impact of poverty on the people of Haiti. The filmmaker was trapped for over 65 hours under the rubble until rescue workers dug him out. He's now safe and sound in Miami’s Jackson Memorial Hospital.
Source: Today (news link)
Health-related iPhone apps are plentiful in the AppStore. I've personally reviewed iMobile Care, that's cheaper than what Mr. Wooley used. Still, have your pick and perhaps share what you're using on your own iPhone.