How long can a patient survive before cardiac arrest causes irreversible brain damage?

The time frame in which a patient can survive before cardiac arrest leads to irreversible brain damage is quite critical, with three minutes often being cited as the guideline. This is due to the fact that the brain requires a continuous supply of oxygen to function adequately. When the heart stops beating, blood flow ceases, and the brain can begin to suffer significant damage within a short period.

At around the three-minute mark, neurons can start to die because they are deprived of oxygen, leading to the potential for irreversible brain injury. However, the degree of damage can vary based on several factors, including the individual's overall health, the presence of any prior neurological deficits, and the immediate actions taken following cardiac arrest, such as the initiation of CPR.

Options that suggest longer survival times, such as seven, ten, or thirteen minutes, do not align with established medical understanding around the urgency of restoring circulation and oxygenation after cardiac arrest to minimize the risk of permanent brain damage. Therefore, the correct answer regarding the duration before irreversible brain injury occurs is three minutes.