What is the most critical action to perform after recognizing a patient in cardiac arrest?

Starting high-quality CPR quickly is the most critical action after recognizing a patient in cardiac arrest because it directly addresses the immediate need to maintain blood circulation and oxygen delivery to vital organs. During cardiac arrest, the heart is not effectively pumping blood, which can lead to rapid organ damage and death within minutes.

High-quality CPR involves a rate of chest compressions of 100 to 120 per minute and ensuring that the compressions are deep enough to create blood flow—about 2 to 2.4 inches for adults. Additionally, it's important to allow full chest recoil between compressions to increase blood return to the heart.

While calling for help, checking for responsiveness, and attaching an AED are important components of the overall response to cardiac arrest, they do not replace the necessity of beginning CPR as soon as possible. Effective CPR can significantly increase the chances of survival until more advanced medical help arrives. The priority is to initiate high-quality chest compressions without delay to keep perfusing the brain and heart, minimizing the damage caused by the lack of blood flow.