The Rules of Three: Air

Priority #1
Three minutes without air.

  Any condition or circumstance that is IDLH (Immediately Dangerous to Life and Health) will have to be taken care of first.
If you or someone around you is in the middle of some type of medical crises or any type of IDLH situation this would be a priority. If your the one not breathing though you probably won't have worry about the rest of the rules.
   I carry a simple first aid kit in my vehicle and one in my pack when I'm out but you can improvise. Even more important get some type of first aid/CPR training, a little knowledge can go a long way. Think about situations before they happen and ways you can improvise items around you to get things under control so to speak.

I'm in no position to give any type of first aid advice but here is good article on The ABC's of Trauma By Dr. Mountaintop

Stay Safe
Bob