What is the next step after Cardiopulmonary Resuscitation (CPR) following one shock shows Ventricular Fibrillation (VFIB)?

From the Guidelines

After one shock shows Ventricular Fibrillation (VFIB), the next step is to continue CPR and administer a second shock, followed by 2 minutes of continuous CPR, as recommended by the 2020 American Heart Association guidelines 1. The priority is to maximize blood flow to vital organs during CPR while allowing time for medications to circulate and take effect before the next rhythm check and potential shock. During this 2-minute CPR cycle:

• Ensure high-quality chest compressions (rate 100-120/min, depth 2-2.4 inches)
• Administer epinephrine 1 mg IV/IO every 3-5 minutes
• Consider advanced airway placement if not already done After 2 minutes of CPR, briefly pause to check the rhythm. If VF/VT persists, deliver another shock and immediately resume CPR. The use of antiarrhythmic drugs, such as amiodarone or lidocaine, may be considered for refractory VF/pVT, as stated in the 2020 guidelines 1, but the primary focus should be on continuous, high-quality CPR and timely defibrillation, as emphasized in the 2018 update 1. Continuous, high-quality CPR is crucial for improving the chances of successful defibrillation and overall survival. The optimal sequence of ACLS interventions, including administration of antiarrhythmic drugs during resuscitation, is still not fully established, but the 2020 guidelines provide a clear framework for the management of VFIB 1.

From the FDA Drug Label

For breakthrough episodes of VF or hemodynamically unstable VT, use 150 mg supplemental infusions of amiodarone (mixed in 100 mL of D5W and infused over 10 minutes to minimize the potential for hypotension) For breakthrough episodes of VF or hemodynamically unstable VT, repeat the Initial Load

The next step after Cardiopulmonary Resuscitation (CPR) following one shock that shows Ventricular Fibrillation (VFIB) is to administer a 150 mg supplemental infusion of amiodarone, also known as repeating the Initial Load, which consists of 150 mg in 100 mL (in D5W) infused over 10 minutes 2 2.

From the Research

Next Steps after Cardiopulmonary Resuscitation (CPR) and Ventricular Fibrillation (VFIB)

• After a single defibrillation attempt, chest compressions should be initiated again immediately for 2 min 3
• The American Heart Association recommends 1 mg epinephrine every 3-5 minutes for standard use in adults 3, 4
• If the first defibrillation attempt is unsuccessful, subsequent defibrillation attempts should be made with the respective highest energy 3
• Antiarrhythmic drugs such as amiodarone or lidocaine may be considered for refractory VF/pVT cardiac arrest, but their use is uncertain and should be based on individual patient needs 5
• Advanced life support providers should be trained to use a manual defibrillation protocol, as semiautomatic external defibrillation may not improve outcomes 6

Rhythm Analysis and Defibrillation

• A two-step analysis through CPR (ATC) algorithm can be used to minimize interruptions during CPR, with an initial analysis during chest compressions and a subsequent compression-free analysis if a shockable rhythm is not detected 7
• The ATC algorithm has been shown to achieve high sensitivity and specificity for detecting shockable rhythms, including ventricular fibrillation (VF) 7

Drug Administration

• Epinephrine dosage should be titrated to an effective level, taking into account the individual patient's needs and the duration of cardiac arrest 4
• An escalating epinephrine dosage concept may be recommended, with higher doses used for patients with prolonged cardiac arrest intervals 4