Cardiopulmonary Resuscitation (CPR) is a time-sensitive intervention used during cardiac arrest. The primary function of chest compressions is to create artificial blood flow, generating pressure within the circulatory system. For CPR to be effective, this artificial circulation must be continuous, as interruptions severely compromise the flow of oxygenated blood. Minimizing any pause in compressions is directly linked to better survival outcomes.
The Maximum Time Limit for Interruptions
Major resuscitation organizations recommend a strict upper limit for the duration of any pause in chest compressions during CPR. This maximum threshold is established at ten seconds for any single interruption. This ten-second limit applies to all necessary breaks, including rhythm checks, ventilation, or preparing for defibrillation. Although ten seconds is the maximum acceptable duration, high-performing resuscitation teams aim to keep interruptions significantly shorter, often five seconds or less. Minimizing delay is important because every second compounds the physiological detriment to the patient.
The Physiological Impact of Pausing Compressions
Pausing chest compressions is detrimental because it immediately collapses the pressure gradient necessary to perfuse the heart muscle. This key measurement is Coronary Perfusion Pressure (CPP), which is the difference between the pressure in the aorta and the pressure in the right atrium during the relaxation phase of a compression. This pressure gradient drives blood into the coronary arteries.
Effective compressions must generate a CPP of at least 15 to 25 millimeters of mercury (mmHg) for the heart to restart. When compressions cease, the CPP instantly drops to zero, causing the heart muscle to rapidly lose its blood supply.
After a pause, it takes multiple compressions to rebuild the necessary pressure. Studies indicate that between five and fifteen compressions are required before the CPP returns to a sustainable level. Consequently, a ten-second pause significantly reduces the total blood flow the patient receives during resuscitation.
Procedures That Require Brief Pauses
Certain actions during a cardiac arrest intervention require a temporary, unavoidable stop in chest compressions to be performed accurately or safely. Analyzing the patient’s heart rhythm, typically done by a defibrillator, requires a pause to halt the electrical interference generated by compressions. Defibrillation, the delivery of an electrical shock, also requires a brief pause; compressions must stop immediately before the shock for safety. After the shock is administered, compressions must resume without delay, keeping the entire pre-shock and post-shock pause within the ten-second maximum.
When an advanced airway device is not in place, providing rescue breaths necessitates a brief interruption. Current guidelines recommend a cycle of thirty compressions followed by two breaths. This brief interruption is necessary for oxygenation but must still adhere to the strict time limit.