When should CPR be performed?

CPR, or cardiopulmonary resuscitation, should be performed when there is no pulse. This is because the absence of a pulse indicates that the heart is not effectively pumping blood, which can lead to a lack of oxygen being delivered to vital organs. Initiating CPR helps to manually pump blood and maintain some level of circulation to the brain and other organs until advanced medical help arrives.

While an unconscious victim may require CPR, being unconscious alone does not guarantee that there is no pulse or that resuscitation is needed. It's crucial to assess the victim's responsiveness and pulse before initiating CPR. The other choices—requesting CPR or the presence of severe pain—do not provide appropriate criteria for performing CPR, as they do not directly address the critical need for circulation and oxygenation in life-threatening situations.