Stolen from a Reddit comment, but awesome nonetheless:
I did CPR on a hamster once. We got to the house fire and got a mom and ~8 year old boy out. We have a policy of asking about pets and the little boy cried and told me where their cage was.
I got inside as the first team in was putting out the fire in the kitchen and saw the cage on a table. I grabbed the cage and went outside. One of the hamsters was fine and moving, but the other was unconscious/dead.
This little boy was crushed. He picked the hamster up and held him up to me and said, you have an ambulance you fix things…please fix him.
The medic unit was doing rest and recovery for the firefighters that were working the fire an doing overhaul. The Chief looked at me and said “Try, and let the kid see what you do to give him closure”.
I put the hamster on the stretcher and grabbed a peds NRB and placed it over the top half of his little furry body. I grabbed some ears to see if I could hear a hamster heartbeat, but I could not pick anything up.
I thought…well I guess CPR works for cats and dogs, why not a hamster? I started compressions(with one fingertip) and kept the 02 flowing.
After a few minutes of this, the little guy started to twitch! He obviously was wiped out, but started moving. I kept petting him, and he was getting better.
The little boy was cheering when he saw his little friend moving around. We left him on oxygen while we cleaned up, and told him that we had no way to know if the hamster was just unconscious when we found him, or if it was worse off and needed a vets care.
We used the medic unit to transport the mom and son to a nearby friends house, and when they got out the hamster was running around in the cage. Seemed fine.