What indicates that tissue damage during cardiac arrest becomes significant?

The indication that tissue damage during cardiac arrest becomes significant after 4 minutes is based on the understanding of how quickly brain and organ tissues begin to suffer from a lack of oxygen when blood circulation ceases. After approximately 4 minutes without adequate blood flow, irreversible damage to brain cells can start to occur due to hypoxia. This relatively short timeframe highlights the critical importance of rapid response and intervention in cases of cardiac arrest.

While brain cells are particularly vulnerable, other tissues and organs can also begin to experience damage, though the brain is typically highlighted as the most sensitive to prolonged oxygen deprivation. As every minute passes in cardiac arrest, the risk of severe outcomes increases sharply. Thus, a response within 4 minutes is crucial to mitigate potential consequences of tissue damage.