Cardiopulmonary Resuscitation (CPR) is a time-sensitive procedure performed when the heart has stopped beating. The most important component of modern CPR protocols is the delivery of high-quality chest compressions. These manual compressions temporarily take over the heart’s function, pushing oxygenated blood to the brain and other vital organs. Because continuous blood flow is paramount for survival and neurologic recovery, the primary goal of any rescuer is to minimize the duration of any necessary interruption.
Minimizing Interruptions for Essential Tasks
The effectiveness of CPR is measured by the compression fraction, the percentage of total resuscitation time spent actively performing chest compressions. Current guidelines emphasize that rescuers should strive for a compression fraction of at least 60% to maintain adequate blood pressure and perfusion. Even brief pauses allow blood pressure to drop significantly, and it takes several compressions to rebuild that pressure once CPR is resumed. Therefore, the core rule for almost all planned interruptions during resuscitation is that they must not exceed 10 seconds in duration.
Trained rescuers performing conventional CPR must pause compressions to deliver rescue breaths to the patient, typically following a 30:2 compression-to-ventilation ratio for adults. The two breaths should be delivered quickly, with the entire ventilation sequence lasting less than 10 seconds before compressions are immediately resumed.
Another planned pause occurs when rescuers must switch positions due to fatigue. High-quality compressions are physically demanding, and a single rescuer’s effectiveness begins to decline significantly after about two minutes. To maintain the proper depth and rate, rescuers should switch out approximately every two minutes, or sooner if the compressor shows signs of tiring. This transition should be executed with maximum efficiency, ideally taking less than five seconds to ensure minimal blood flow interruption.
Temporary Stoppage for Patient Assessment
Stoppages are required for critical patient assessments, often involving advanced equipment like an Automated External Defibrillator (AED).
When an AED is brought to the scene, compressions must be halted temporarily so the device can accurately analyze the patient’s heart rhythm. The AED will verbally prompt the rescuer to stop touching the patient during this analysis period.
If a shockable rhythm is detected, compressions must be paused again immediately before and during the shock delivery to ensure the safety of the rescuers. The moment the shock is delivered, or if the AED advises “no shock,” the rescuer must immediately resume compressions without waiting for any further assessment. The entire pause for rhythm analysis and shock delivery must be kept to less than 10 seconds.
Trained professionals may also stop compressions briefly to check for the Return of Spontaneous Circulation (ROSC), which is indicated by a definitive pulse or normal breathing. This check is typically performed after every two minutes of CPR, but this assessment, like all others, must be completed quickly. If no signs of life are detected within 10 seconds, the rescuer must immediately restart chest compressions. Pausing for the placement of advanced airway devices by trained personnel is necessary, but this pause must also be kept as short as possible, ideally under 10 seconds.
Criteria for Ending CPR Efforts
Chest compressions are permanently stopped only when one of several definitive criteria is met, marking the end of the resuscitation attempt by the rescuer.
The most positive reason to stop is the definitive presence of ROSC (Return of Spontaneous Circulation), meaning the patient begins to move, speak, or breathe normally. At this point, the rescuer should cease compressions and monitor the patient until emergency medical services (EMS) arrive.
The most common reason for a lay rescuer to stop CPR is the arrival of advanced medical personnel, such as paramedics or emergency medical technicians. Once these trained professionals arrive and assume responsibility, the initial rescuer can stop compressions. Continuing to perform compressions when a highly-trained team has taken charge is unnecessary unless directed otherwise.
If a rescuer is alone and becomes physically unable to continue delivering effective compressions, it is acceptable to stop. High-quality CPR is physically exhausting, and ineffective compressions are not beneficial to the patient. Similarly, if the scene becomes unsafe for the rescuer due to changing circumstances, the rescuer should move to safety and stop compressions. While professional medical personnel follow specific protocols regarding Do Not Resuscitate (DNR) orders, lay rescuers should generally continue CPR until one of the other definitive stopping criteria is met.