Final answer:
A person may pass out after 3 minutes without oxygen and potentially sustain brain damage within five minutes. Immediate CPR can increase survival chances, especially in cases like cold water drownings. Treating carbon monoxide poisoning quickly with oxygen also helps in recovery.
Step-by-step explanation:
How Long Until a Person Passes Out Without Oxygen?
When deprived of oxygen, a person can pass out within a very short timeframe. Typically, a human cannot survive without breathing for more than about 3 minutes. Brain damage is likely within five minutes without oxygen, and death may occur within ten minutes. In cases of drowning, particularly in cold water, the chances of recovery can be better if resuscitation is started within minutes, even after prolonged periods. Initially, the drive to breathe is more influenced by high carbon dioxide levels in the blood rather than low oxygen concentrations.
For those affected by carbon monoxide poisoning, giving oxygen via a non-rebreather mask can reduce the half-life of carbon monoxide in the body significantly, aiding recovery. It's crucial for rescuers to act swiftly when someone is unconscious due to oxygen deprivation, as administering CPR immediately can increase the chances of survival and reduce the likelihood of brain damage.