What action should a rescuer take when encountering a victim who shows no signs of life?

When encountering a victim who shows no signs of life, the appropriate and critical action for a rescuer is to check for a pulse and, if none is detected, initiate CPR immediately. This step is essential because CPR is designed to restore circulation and provide oxygen to the body's vital organs, particularly the brain and heart, which can sustain irreversible damage within minutes without blood flow.

Checking for a pulse confirms the victim's cardiac output status, allowing the rescuer to determine the next steps accurately. If the victim has no pulse, starting chest compressions helps to manually circulate blood and increase the chances of survival until advanced medical help arrives. Initiating rescue breaths without assessing the victim’s pulse could delay crucial care, and solely monitoring the victim or leaving them in the water poses greater risks and neglects the need for immediate lifesaving measures. Therefore, assessing for a pulse and beginning CPR if necessary is a vital and lifesaving action in an emergency scenario.