When should CPR be stopped to perform a rhythm check for potential defibrillation (defibrillator) in a cardiac arrest scenario?

When to Stop CPR for Rhythm Check and Defibrillation

CPR should be stopped for rhythm checks every 2 minutes (or after approximately 5 cycles of 30:2 compressions-to-ventilations), and immediately when a defibrillator is ready to analyze the rhythm for potential shock delivery.

Timing of Rhythm Checks During CPR

The 2020 American Heart Association (AHA) guidelines for cardiopulmonary resuscitation provide clear recommendations on when to interrupt CPR for rhythm analysis:

Standard 2-Minute CPR Cycles

• Perform continuous CPR for 2 minutes (approximately 5 cycles of 30:2 compressions-to-ventilations) before pausing for rhythm analysis 1
• Minimize all interruptions in chest compressions, including those for rhythm checks
• After each 2-minute cycle, briefly pause CPR to check rhythm and determine if defibrillation is needed 1

When Using an AED

• When an AED becomes available, apply it immediately and follow the device prompts
• The AED will prompt to pause CPR for rhythm analysis
• If a shockable rhythm is detected, the AED will charge and prompt to deliver a shock 1
• Resume CPR immediately after shock delivery without checking for a pulse, beginning with chest compressions 1

When Using a Manual Defibrillator

• When a manual defibrillator reveals VF/VT, the first provider should resume CPR while the second provider charges the defibrillator 1
• Once charged, pause CPR briefly to "clear" the patient and deliver the shock
• Resume CPR immediately after shock delivery without checking for a pulse or rhythm 1

Rationale for Minimizing Interruptions

The 2005 AHA guidelines marked a significant change in approach, emphasizing the importance of minimizing interruptions in chest compressions 1:

• Modern biphasic defibrillators have high first-shock efficacy (>90%)
• After defibrillation, most victims demonstrate a non-perfusing rhythm for several minutes
• Immediate resumption of CPR after shock delivery is crucial for maintaining coronary perfusion
• Research shows that the majority of patients remain pulseless for over 2 minutes following defibrillation attempts 2

Common Pitfalls to Avoid

1. Checking for pulse immediately after defibrillation

   • This is a common error made by 54.2% of ACLS providers in one study 3
   • Always resume CPR immediately after shock delivery without checking for pulse

2. Excessive interruptions for rhythm checks

   • Limit rhythm checks to every 2 minutes unless there is a clinical change
   • Each interruption in compressions decreases coronary perfusion pressure

3. Delayed resumption of CPR after shock

   • Even a few seconds delay between shock and resuming compressions can decrease the probability of shock success 1
   • The shorter the interval between the last compression and shock delivery, the more likely the shock will be successful

Special Considerations

• In specific in-hospital settings with continuous monitoring, the sequence may be modified at the physician's discretion 1
• For pediatric patients, the same principles apply: perform CPR for 2 minutes between rhythm checks 1
• When an advanced airway is in place, provide continuous chest compressions without pausing for ventilations (10 breaths/minute) 1

By following these guidelines and minimizing interruptions in chest compressions, you can optimize the chances of successful resuscitation and improve patient outcomes.