Cardiopulmonary resuscitation (CPR) circulates oxygenated blood during cardiac arrest until advanced medical intervention is available. While the rate and depth of chest compressions are widely recognized metrics, the Chest Compression Fraction (CCF) is a powerful indicator of CPR quality. CCF measures continuity, determining how much of the total resuscitation effort is spent actively moving blood throughout the body.
Defining the Chest Compression Fraction
CCF stands for the Chest Compression Fraction, representing the proportion of the total cardiac arrest time during which chest compressions are actively performed. It is calculated by dividing the total time spent delivering compressions by the total time of the resuscitation attempt, including all pauses. For example, if a ten-minute resuscitation includes four minutes of pauses, the CCF is 60%.
This metric is distinct from the compression rate, which measures the number of compressions per minute while a rescuer is on the chest. CCF accounts for all interruptions, serving as a comprehensive measure of efficiency. Current guidelines recommend that high-quality CPR maintain a CCF of at least 60%, with optimal systems aiming for 80% or higher.
The Critical Role of CCF in Patient Outcomes
The importance of a high Chest Compression Fraction is rooted in the need to maintain adequate pressure to perfuse the heart and brain. Chest compressions manually generate blood flow and pressure, but this pressure drops rapidly to zero the moment compressions stop. The pressure required to perfuse the heart muscle, known as coronary perfusion pressure (CPP), is a primary predictor of whether the heart can be successfully restarted.
Every pause, even those lasting only a few seconds, causes a drop in CPP. Once compressions resume, it takes multiple cycles to rebuild the pressure back to an effective level. This pressure “ramp-up” means that frequent interruptions lead to prolonged periods of low blood flow to the heart and brain. Maximizing the CCF is directly associated with a greater likelihood of achieving the Return of Spontaneous Circulation (ROSC) and better neurological recovery.
Strategies for Maximizing the Chest Compression Fraction
Achieving a high CCF requires minimizing all sources of interruption during resuscitation. One of the primary strategies is the efficient management of pauses required for rhythm analysis and defibrillation. Resuscitation teams must strive to keep these pre-shock and post-shock pauses to less than ten seconds, which significantly limits the drop in perfusion pressure.
Another major cause of interruption is ventilation, especially when using a traditional compression-to-breath ratio. Implementing asynchronous ventilation, where quick breaths are delivered without stopping compressions, or utilizing strategies like passive oxygenation can dramatically increase the CCF.
To combat rescuer fatigue, compressors should be rotated every two minutes with minimal transition time. The use of real-time CPR feedback devices and mechanical compression devices can help teams monitor performance and deliver consistent, uninterrupted compressions.