When should CPR be initiated?

CPR should be initiated when there are indications that the patient is unresponsive and not breathing normally, typically leading to a situation in which they may be in cardiac arrest. A valid living will, which may specify a patient's wishes regarding resuscitation effort, can impact the decision to begin CPR. In a scenario where such a document is unavailable, healthcare providers generally are compelled to perform CPR to ensure that the patient receives appropriate emergency care until further directives can be obtained or medical personnel determine that resuscitation shouldn't continue due to other legal or ethical considerations.

In contrast, starting CPR during a heart attack or when a patient is breathing normally is not appropriate, as both situations do not typically indicate the need for CPR. If someone has fainted but is still breathing and has a pulse, CPR is also not indicated until those vital signs deteriorate. Thus, the context surrounding the lack of a living will emphasizes the importance of erring on the side of preserving life during emergencies where clear instructions are not available.