system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: if someone is strangled but can still be revived with CPR - why can their body not start breathing again on its own ?
gpt
When someone is strangled the problem is not lack of oxygen (or excess CO2), since the body can handle that for a few minutes. Instead, blocking the respiratory tract results in a strong negative pressure in the lungs as they try to breathe against the blockage. This pulls fluid out of the veins and into the air sacs, so it’s much more like drowning.

Thus cardiac resuscitation alone won’t work, because the lungs are full of fluid that is hard to remove.