High-quality cardiopulmonary resuscitation (CPR) is the most important factor influencing survival from cardiac arrest. High-quality CPR is defined by uninterrupted chest compressions. When two or more trained rescuers are present, two-rescuer CPR is the gold standard for maintaining this quality over time. This team effort allows one person to focus on compressions while the other manages the airway and rescue breaths, requiring regular switching of roles to combat rescuer fatigue.
The Standard Rescuer Switch Interval
Responders should switch roles every two minutes, or approximately five cycles of compressions and breaths. This timing is standardized across major international resuscitation guidelines, including the American Heart Association (AHA). This structured rotation proactively maintains the effectiveness of chest compressions.
The two-minute interval is a fixed procedural guideline followed regardless of whether the compressor feels tired. In adult CPR using the 30 compressions to 2 breaths ratio, this period translates to about five full cycles. Rescuers should switch roles at a natural pause point, such as after the two rescue breaths of the fifth cycle or during an automated external defibrillator (AED) analysis.
Strict adherence to this predetermined interval helps prevent the subtle decline in compression quality when a rescuer is fatigued. Delaying the switch until the compressor reports feeling tired is not recommended, as objective data shows that performance begins to decrease before the rescuer subjectively perceives exhaustion. The two-minute mark serves as a reliable, objective timer.
The Physiological Necessity of Switching
The rationale for the two-minute switch is rooted in the rapid onset of physical fatigue during the strenuous act of chest compressions. Performing compressions at the required depth and rate demands significant physical exertion, involving the rescuer’s core, arms, and back muscles. Studies consistently show that compression quality drops within two minutes of continuous effort.
This decline manifests as a reduction in compression depth and a deviation from the recommended rate. For an adult, compressions must be delivered to a depth of at least 2 inches (5 centimeters) at a steady rate of 100 to 120 compressions per minute. As fatigue sets in, the force applied decreases, causing compressions to become too shallow, which results in insufficient blood flow to the heart and brain.
Fatigue also negatively impacts the “compression fraction,” which is the percentage of time spent actively compressing the chest. Maintaining a compression fraction greater than 80% is a benchmark of high-quality CPR. When the compressor tires, they may take longer pauses, slow their rate, or fail to allow the chest to fully recoil, all of which reduce this fraction and compromise the circulation of oxygenated blood.
Minimizing the Hands-Off Time During Transition
While switching is necessary, the transition must be executed flawlessly to avoid excessive hands-off time, which is any pause in chest compressions. The goal is to keep this interruption to an absolute minimum, ideally under 10 seconds. Every second without compressions directly decreases the patient’s chance of survival by reducing blood flow to vital organs.
Efficient switching relies on clear, anticipatory communication between the two responders. The rescuer managing the airway should announce the upcoming switch, for instance, by stating “switch on the next cycle.” This verbal cue allows the incoming compressor to be ready and positioned beside the patient, often kneeling opposite the current compressor.
As the outgoing compressor finishes the final set of compressions, they should immediately disengage and move away, allowing the new compressor to take over without obstruction. The incoming rescuer must quickly establish proper hand placement and begin compressions immediately. Practicing this coordinated movement and clear verbal handoff is essential for minimizing the gap in life-sustaining chest compressions.