Which of the following is a crucial sign during a cardiac arrest?

During a cardiac arrest, grey pallor is a critical sign because it indicates a lack of adequate blood flow and oxygen to the tissues. This pallor is often due to the body shutting down its circulation, prioritizing blood flow to vital organs while resulting in diminished perfusion to the skin and extremities. It is a visual cue that can help responders quickly assess the severity of the situation.

In contrast, a rapid pulse might indicate other conditions such as anxiety, fever, or shock rather than a direct sign of cardiac arrest. A persistent cough is generally associated with respiratory issues and not a direct sign of cardiac arrest. Elevated temperature typically suggests infection or inflammation rather than providing immediate evidence of cardiovascular collapse. Therefore, grey pallor serves as a more definitive indicator of cardiac arrest, highlighting the critical need for immediate intervention.