In which scenario is CPR necessary?

CPR is necessary when there is no pulse because this indicates that the heart is not effectively pumping blood to the body's organs and tissues, leading to a lack of oxygen. The absence of a pulse signifies that the victim is in cardiac arrest, which is a critical emergency requiring immediate intervention. Performing CPR helps maintain blood flow to vital organs, particularly the brain, until professional medical help can arrive or an automated external defibrillator (AED) can be used.

In contrast, breathing that is laborious may indicate respiratory distress wherein specific support could be beneficial without the need for CPR. A conscious victim is likely still breathing and has a pulse, hence they do not require CPR. Similarly, if the victim is talking, it means they have an effective airway and circulation, indicating that CPR is not necessary in that situation.