CPR, or Cardiopulmonary Resuscitation, is an emergency procedure performed during cardiac arrest when the heart has stopped beating. The technique combines chest compressions with artificial ventilation to manually circulate oxygenated blood. The goal of CPR is to prevent irreversible damage to the brain and vital organs until medical treatment can restore a natural heartbeat. The decision to stop CPR, or “call time of death,” is a complex process governed by protocols based on the rescuer’s training and the clinical setting.
When Lay Rescuers Should Stop CPR
For a bystander without professional medical training, the decision to stop CPR is based on practical circumstances, not medical judgment. The primary instruction is to continue performing high-quality chest compressions without interruption until professional help arrives.
A lay rescuer should cease compressions immediately when Emergency Medical Services (EMS) personnel or other trained first responders arrive and take over the effort. Another valid reason to stop involves the scene becoming unsafe for the rescuer, such as the presence of fire or hazardous environments.
Physical exhaustion is a practical reason for a lay rescuer to stop performing CPR, especially if alone. Effective chest compressions require significant effort, and if the rescuer is too tired to maintain quality, cessation is appropriate. If a second person is present, rescuers should alternate every two minutes to maintain compression quality. A final reason for stopping is the clear return of signs of life, such as the person beginning to move or breathe normally.
Medical Protocols for Terminating Resuscitation
The decision to terminate resuscitation efforts by medical professionals is guided by strict, evidence-based protocols that differ between out-of-hospital and in-hospital settings. For Emergency Medical Services (EMS) responding to out-of-hospital cardiac arrest (OHCA), termination of resuscitation (TOR) rules apply after a specific duration of unsuccessful advanced life support. Many protocols suggest considering termination after 20 to 30 minutes of continuous, high-quality CPR without the return of spontaneous circulation (ROSC).
Protocols rely on factors such as whether the arrest was witnessed by EMS, if bystander CPR was provided, and the initial cardiac rhythm. For example, an unwitnessed arrest with a non-shockable rhythm (asystole or PEA) combined with a lack of ROSC strongly predicts futility. In the hospital setting, the treating physician makes the decision based on broader clinical data, including the patient’s underlying health status and the duration of the attempt.
Objective clinical measures, such as monitoring end-tidal carbon dioxide (ETCO2) levels, are used to assess futility. Persistently low ETCO2 values (below 10 or 15 mmHg after 20 minutes) indicate poor circulation to the lungs and a poor prognosis. If advanced measures fail to produce ROSC after an appropriate time, the medical team formally ceases efforts.
Criteria for Pronouncing Death
The act of “calling time of death” is a formal, legal pronouncement made after resuscitation efforts have been terminated or were never initiated. This declaration is typically made by a physician or authorized medical personnel. The recorded time of death is the exact moment the healthcare provider declares life extinct.
The presence of a valid Do Not Resuscitate (DNR) order or advance directive preempts any resuscitation attempt. Medical personnel must honor this legally binding document and will not initiate or will immediately cease CPR. Similarly, if obvious and irreversible signs of death are present upon arrival, CPR is considered futile and will not be started.
Definitive signs of death include dependent lividity (pooling of blood causing skin discoloration) and rigor mortis (stiffening of joints and muscles). Catastrophic injuries incompatible with life, such as decapitation, also justify non-initiation of CPR and immediate pronouncement. If a full resuscitation attempt fails to achieve ROSC, pronouncement is made after confirming the absence of a pulse, breathing, and response to stimuli.