- When a doctor -- or some other appropriate emergency medical provider -- tells you to stop.
- When you become exhausted and cannot continue (this gets messy, as we'll see below).
- When the victim begins yelling at you to stop hitting him in the chest (this really happened to me). In other words, when the victim gets better.
Stopping CPR in Civilization
When the paramedics or emergency medical technicians arrive at the scene, they are going to take over CPR. Just because they've walked in the door, however, don't stop immediately. The first responders probably still have a few tools to set up before they can jump in where you are going to leave off. When they're ready, they'll tell you to stop CPR.
If a doctor is available, he or she might tell you to stop CPR because a medical provider is going to take over, or because there's nothing left to do and it's time to stop.
Stopping CPR When Far from Professional Help
When you're alone, though, is the toughest time to make this decision. Let's go back to the Amazon rainforest for a moment. You and Dr. Livingston (no "e" -- Livingstone was in Africa) are tromping around in the bush when Livingston collapses in sudden cardiac arrest. You begin CPR right away. Whether or not CPR alone is enough (and it very well might be), you don't give up hope and continue to pump on Doc L's chest for more than 15 minutes to no avail. When, pray tell, do we end this thing?
There won't be any ambulances coming along in the jungle. There isn't any 911 for you to call. No doctor is going to parachute in just to give you the A-OK to discontinue heroic measures (fancy medical talk for "stop CPR").
So, how do we know? Well, how tired -- still in the rainforest and now very much alone -- can you afford to become? Are you still going to have the energy to find shelter and walk back to civilization after two hours of vigorous chest compressions? There's an emotional question to consider here as well: How tired do you have to be before you'll forgive yourself for quitting?
Only you can decide that.
On the other hand, if the good doctor opens his eyes, grabs your hand and asks you politely to quit pushing on his chest, then oblige the poor man and let's get on with our exploration of the Amazon. Fine work!