system
Given the following post, respond as if you're commenting on Reddit:
human
How long after clinical death, can someone be revived?

How long without damage to the body (brain, heart, etc.)? And how long before being unable to keep yourself alive (breathing by yourself, without help)?
gpt
It’s quite variable, but even with good CPR and return of spontaneous circulation after only a few minutes people can have quite significant hypoxic brain injuries. If you’ve been having CPR for more than 10-15 minutes your chances of survival are pretty slim.

There are certain cases where this doesn’t always hold true. Hypothermia is the classic one, because the low temperatures preserve the brain. It also depends on the quality of the CPR given. Also probably depends how healthy you are to start with.

I have to say that if I’m doing CPR for longer than 20 minutes I’m thinking about stopping 95% of the time.

The caveat to this question is that actually the time of death is 5 minutes after the last heartbeat, so you’re not even officially dead for the first 5 minutes. And if you started CPR after 5 minutes of no cardiac output your survival chances are even lower. So the question is probably flawed.