Cardiopulmonary resuscitation (CPR) is an emergency procedure performed when a person’s heart stops beating, helping maintain vital blood flow to the brain and heart. Chest compressions are the core of CPR. For CPR to be most effective, continuous compressions are critical, and any pauses should be kept to a minimum.
The Critical Role of Continuous Compressions
Continuous chest compressions are important because each compression builds pressure to circulate oxygen-rich blood to the brain and heart. Even brief pauses cause a significant drop in blood pressure and reduce oxygen delivery. It takes several compressions to rebuild this pressure after an interruption, leading to lost time and reduced overall effectiveness.
The concept of “coronary perfusion pressure” (CPP) highlights the importance of continuous compressions. CPP is the pressure gradient driving blood flow to the heart muscle during CPR. Maintaining an adequate CPP, typically at least 15 mmHg, ensures the heart receives enough blood flow to restart, making successful resuscitation less likely. Interruptions can severely lower this pressure.
Specific Instances Requiring Pauses
While continuous compressions are the goal, certain situations necessitate brief pauses during CPR performed by a lay rescuer.
Rescue Breaths
One common reason is to deliver rescue breaths in conventional CPR. After 30 chest compressions, the rescuer pauses briefly, typically for no more than 10 seconds, to deliver two rescue breaths. These breaths should be given quickly, about one second per breath, with the chest visibly rising.
AED Use
Another instance involves the use of an Automated External Defibrillator (AED). When the AED analyzes the heart rhythm, compressions must be paused so the device can accurately assess the heart’s electrical activity. If the AED determines a shock is necessary, compressions are paused immediately before and during the shock delivery to ensure safety and effective energy transfer. After the shock, compressions should resume immediately.
Role Switching and Patient Movement
Rescuers may also need to pause compressions briefly when switching roles due to fatigue. To maintain high-quality compressions, rescuers should aim to switch every two minutes, with the transition ideally taking less than five seconds. In rare cases, if the patient must be moved for safety reasons or to a firmer surface, compressions may be briefly interrupted for the shortest possible duration.
Strategies for Minimizing Pause Time
Minimizing the duration of necessary pauses is crucial for maximizing “hands-on” time, also known as the chest compression fraction (CCF). The goal is to achieve a CCF of at least 60%, with an ideal target of 80% or higher.
One strategy for reducing pause time with an AED is to pre-charge the device during the last few compressions before rhythm analysis, if the AED model allows. This reduces the “peri-shock pause” when no compressions are occurring.
When multiple rescuers are present, coordinating seamless switches in compression roles helps reduce interruptions. Rescuers can prepare to take over compressions just as the current compressor approaches the two-minute mark, ensuring a smooth transition without a significant break in blood flow. For conventional CPR, delivering rescue breaths efficiently, taking about one second per breath, minimizes the pause associated with ventilations. For lay rescuers uncomfortable or unable to provide breaths, “hands-only” CPR is an alternative. This eliminates pauses for breaths entirely, and has been shown to be as effective as conventional CPR in the first few minutes of an out-of-hospital cardiac arrest for adults.