New York State Basic Emergency Medical Technician (EMT-B) Practice Exam

When is brain function at the highest risk due to lack of oxygen?

1. 3 minutes

2. 10 minutes

3. 15 minutes

4. 30 minutes

The correct answer is: 3 minutes

Brain function is at the highest risk due to lack of oxygen within the first few minutes of deprivation. The brain is highly dependent on a continuous supply of oxygen to maintain its vital functions and overall health. After approximately 3 minutes without oxygen, irreversible brain damage can start to occur. This critical time frame underscores the importance of rapid intervention in emergencies involving cardiac arrest or respiratory failure. Beyond this period, the risks of severe brain injury continue to increase, and the likelihood of the brain sustaining permanent damage greatly escalates. By the time 10 minutes have passed, significant damage is almost certain, and after 15 to 30 minutes, the chances of survival with full brain function become exceedingly slim. Hence, the emphasis on the initial 3-minute window as a crucial period for brain function highlights the necessity for immediate medical attention in scenarios where oxygen supply is compromised.