What should you do immediately after you determine that a person is unresponsive and has no pulse?

When you determine that a person is unresponsive and has no pulse, the immediate course of action is to begin CPR. This is because the absence of a pulse indicates that the heart is not functioning effectively to circulate blood, which is vital for delivering oxygen to the brain and other organs. CPR helps maintain blood flow to the organs and can be crucial in preserving brain function until advanced medical help arrives.

Starting chest compressions helps create artificial circulation, providing the body with the oxygen it needs, especially the brain, which can begin to suffer irreversible damage within minutes without oxygen. Therefore, initiating CPR as soon as possible is vital for improving the person's chances of survival and recovery.

Calling 911 is certainly important, but it should happen either simultaneously with or immediately after beginning CPR, rather than delaying the start of chest compressions. Checking for breathing is also a necessary step in the assessment but should not delay the initiation of CPR; if the person is unresponsive and has no pulse, the priority is to start CPR without delay. Waiting for help to arrive would be inappropriate as it could lead to a greater risk of severe outcomes.