Cardiopulmonary resuscitation (CPR) is an emergency procedure performed when a person’s heart has stopped beating effectively. It combines chest compressions with rescue breaths to manually maintain blood flow until further medical intervention is available. The primary goal is to circulate oxygenated blood to the brain and heart muscle, preventing tissue damage and increasing the chance of survival from sudden cardiac arrest.
The Importance of Continuous Chest Compressions
Even brief interruptions in chest compressions significantly reduce the effectiveness of CPR. This is due to coronary perfusion pressure, which is the pressure that drives blood flow to the heart muscle. During compressions, this pressure gradually builds up with each push.
When compressions stop, the coronary perfusion pressure immediately drops to zero within seconds. It takes several compressions, often 6 to 10 or more, to rebuild this pressure to a level that supports a spontaneous heartbeat. The time during which no compressions are delivered is known as “hands-off time,” and minimizing this period is vital for high-quality CPR.
Pauses Required by Standard CPR Protocols
Pauses in chest compressions are necessary only to perform specific, protocol-mandated interventions that improve the patient’s chance of survival. One required pause occurs when delivering rescue breaths in the standard compression-to-ventilation ratio. For example, a single adult rescuer without an advanced airway uses 30 compressions followed by two breaths. These breaths should be delivered quickly, and compressions must resume immediately afterward.
The most common and impactful required pause occurs with the use of an automated external defibrillator (AED) or manual defibrillator. Compressions must be briefly stopped so the device can analyze the heart’s electrical rhythm, and again just before the electrical shock is delivered. Current guidelines emphasize keeping the pause before the shock, known as the pre-shock pause, to less than ten seconds. Studies have shown that even a one-second increase in the pre-shock pause can decrease the likelihood of achieving a spontaneous circulation return.
Another necessary interruption in a team setting is the planned rotation of the rescuer performing compressions. High-quality compressions are physically demanding, and quality deteriorates significantly after about two minutes due to fatigue. Rescuers are instructed to switch positions approximately every two minutes, and this transition must be coordinated to limit hands-off time to seconds. Less frequent pauses may be needed for the placement of advanced airway devices, but these should also be kept brief.
Common Sources of Unnecessary Compression Interruptions
Many pauses during a resuscitation attempt are not mandated by protocol and represent logistical or human errors. One frequent source of unnecessary downtime is the delay in initiating compressions immediately upon recognition of cardiac arrest. Hesitation or waiting for an AED to arrive before starting wastes valuable time before blood flow is established.
Poor communication and coordination among a resuscitation team can also lead to avoidable pauses. For example, if roles are not clearly assigned, multiple providers may attempt to perform the same task, or equipment may not be ready when needed. Checking for a pulse when it is not required by the algorithm is another frequent, non-protocol-driven cause of interruption. These unnecessary pulse checks should be limited to no more than ten seconds.
Other common interruptions include delays in preparing and attaching the defibrillator pads or momentarily stopping compressions to move the patient a short distance. Establishing intravenous access to administer medications has been linked to prolonged pauses when not properly coordinated with ongoing compressions. These logistical missteps reduce the time the patient receives blood flow, negatively impacting the outcome.
Techniques for Minimizing Compression Interruption Time
Strategies employed in high-performance CPR focus on reducing the duration of every pause, both necessary and unnecessary. One effective technique is to pre-charge the defibrillator while compressions are still being delivered. This ensures the electrical shock is ready the moment compressions stop for rhythm analysis, significantly shortening the pre-shock pause.
For planned rescuer rotations, teams use a countdown or a clear verbal cue, such as “switch on the count of five,” to ensure a seamless transition. When an advanced airway is placed, continuous compressions can be maintained, and breaths are delivered asynchronously. This means the compressor does not need to pause for ventilation. The goal of these efforts is to maximize the chest compression fraction, which is the percentage of total resuscitation time spent performing compressions. Guidelines recommend achieving a compression fraction of at least 80%.