Cardiopulmonary resuscitation (CPR) is a manual intervention performed during cardiac arrest to circulate oxygenated blood to the brain and other organs until professional medical help arrives or the heart resumes beating. CPR is defined by a set of precise, measurable standards known as “High-Quality CPR.” This gold standard requires strict adherence to specific parameters for compression rate, depth, and technique. Delivering CPR that meets these standards is the single most important factor influencing a patient’s outcome following cardiac arrest.
The Standard Rate of Compression
The recommended rate for chest compressions in high-quality CPR is universally set at 100 to 120 compressions per minute for all age groups, including adults, children, and infants. The guideline provides a minimum threshold of 100 compressions per minute to ensure adequate blood movement.
The upper limit of 120 compressions per minute is just as important as the lower one for maintaining effective circulation. When rescuers exceed this maximum rate, the quality of the compressions often decreases. Specifically, faster rates can lead to an inadequate compression depth and can also prevent the chest from fully expanding between pumps.
Survival rates decrease significantly when the compression rate falls outside of this 100 to 120 per minute window. Audio feedback devices and metronomes are often used in professional settings to help maintain this consistent rhythm and avoid the detrimental effects of compressing too quickly or too slowly.
Optimizing Blood Flow and Perfusion
The 100 to 120 compressions per minute rate is tied to the physiological goal of CPR: creating artificial circulation to perfuse the brain and heart. Chest compressions work by increasing the pressure within the chest cavity, which squeezes the heart between the sternum and the spine, propelling blood into the arteries.
When the compression rate is too slow, for example below 100 per minute, the total volume of blood circulated over time is insufficient to sustain the vital organs. This reduced circulation quickly leads to a lack of oxygen and nutrients, which diminishes the chances of a successful resuscitation. Conversely, if compressions are performed too rapidly, the heart does not have enough time to completely refill with blood before the next compression begins.
Coronary perfusion pressure (CPP) is generated during the relaxation phase—the moment the chest recoils between compressions—and supplies oxygen to the heart muscle. If the compression rate is too fast, the duration of this relaxation phase is shortened, which significantly lowers the CPP. A reduced CPP means the heart muscle becomes starved of oxygen, making it less likely to respond to defibrillation or resume a natural rhythm. The 100 to 120 rate ensures sufficient pumps while allowing adequate time for the heart to refill and perfuse itself.
Additional Components of High-Quality CPR
High-quality CPR includes several other important components besides rate that must be maintained to maximize patient survival. The first is ensuring adequate compression depth. For an adult, the chest must be compressed at least 2 inches (5 centimeters), but not more than 2.4 inches (6 centimeters). Compressions that are too shallow fail to create the necessary pressure to circulate blood, while compressions that are too deep can increase the risk of injury.
Full chest recoil must be allowed after every compression. This means the rescuer must completely lift their weight off the patient’s chest to allow the chest wall to spring back to its normal resting position. Full recoil creates a negative pressure within the chest, which is necessary to draw blood back into the heart from the veins. Failing to allow for this full recoil significantly impairs the heart’s refilling process, which decreases the effectiveness of the next compression.
Minimizing interruptions is the third main component, quantified by the chest compression fraction (CCF). The CCF measures the proportion of resuscitation time spent actively performing compressions. High-quality CPR aims for a CCF of at least 60%, with many professional guidelines recommending a goal of over 80%. Pauses for interventions like ventilation, checking for a pulse, or preparing a defibrillator must be kept extremely brief, ideally under 10 seconds. Even short interruptions cause a rapid drop in blood pressure and perfusion, which requires a lengthy period of continuous compressions to rebuild.