What is the management protocol for Ventricular Fibrillation (Vfib) in Advanced Cardiovascular Life Support (ACLS)?

ACLS Management of Ventricular Fibrillation

For ventricular fibrillation, immediately deliver an unsynchronized shock at 200J (or manufacturer-recommended biphasic energy), resume high-quality CPR starting with chest compressions, establish IV/IO access, give epinephrine 1mg every 3-5 minutes, and administer either amiodarone 300mg or lidocaine 1-1.5mg/kg after the second shock if VF persists. 1, 2, 3

Immediate Defibrillation Protocol

For witnessed VF with a defibrillator immediately available, deliver the first shock without any preceding CPR. 1 The energy sequence follows a specific pattern:

• First shock: 200J (monophasic) or per manufacturer recommendation for biphasic (typically 120-200J) 1, 2, 3
• Second shock: 200-300J if first unsuccessful 1, 3
• Third shock: 360J if second unsuccessful 1, 3
• Deliver shocks in rapid succession without intervening CPR between the first three attempts 1

After any shock, immediately resume CPR starting with chest compressions without checking for a pulse. 3 The first shock converts approximately 85% of VF cases. 1

High-Quality CPR Requirements

Between defibrillation attempts, maintain these specific parameters:

• Compression rate: 100-120 per minute 1, 2
• Compression depth: at least 2 inches (5 cm) 1, 2
• Allow complete chest recoil between compressions 1, 2
• Minimize interruptions to less than 10 seconds 2, 3
• Rotate compressors every 2 minutes to prevent fatigue 1, 2
• Compression-to-ventilation ratio of 30:2 until advanced airway placed 1

Medication Administration Sequence

After the second unsuccessful shock, establish IV or IO access and begin medications: 2, 3

Epinephrine

• Dose: 1mg IV/IO every 3-5 minutes throughout the resuscitation 1, 2, 3, 4
• Continue until return of spontaneous circulation (ROSC) or termination of efforts 3

Antiarrhythmic Drugs (After 2-3 Shocks)

Either amiodarone OR lidocaine may be used - the 2018 guidelines removed amiodarone's previous preference, making them equivalent choices: 1

Amiodarone:

• First dose: 300mg IV/IO bolus 1, 2, 4
• Second dose: 150mg IV/IO if VF recurs 1, 2, 4
• Infuse over 10 minutes to minimize hypotension 1
• After ROSC, continue infusion at 1mg/min for 6 hours, then 0.5mg/min 1, 4

Lidocaine (if amiodarone unavailable):

• First dose: 1-1.5mg/kg IV/IO 1, 2
• Second dose: 0.5-0.75mg/kg IV/IO 1, 2
• Maintenance infusion: 1-4mg/min after ROSC 1

Advanced Airway Management

Once IV/IO access secured, place an advanced airway (endotracheal tube or supraglottic device): 2

• Confirm placement with waveform capnography 1, 2
• After airway placement, deliver 1 breath every 6 seconds (10 breaths/min) with continuous chest compressions 1
• Avoid excessive ventilation - this decreases cardiac output during CPR 2, 3

CPR Quality Monitoring

Use objective measures to guide resuscitation quality:

• Target PETCO2 >10 mmHg during CPR 1, 2
• If PETCO2 <10 mmHg, improve compression quality 1
• Abrupt sustained increase in PETCO2 to >40 mmHg indicates ROSC 1
• If available, target diastolic arterial pressure >20 mmHg 1, 2

Refractory VF Management

If VF persists after 3 shocks plus medications, consider these interventions:

• Verify pad/paddle position and contact 1
• Change pad position (anterior-posterior vs. anterior-lateral) 1
• Give additional amiodarone 150mg for breakthrough VF 4
• Consider double sequential defibrillation (DSD) - though not in formal guidelines, emerging evidence supports this 5, 6
• Consider low-dose esmolol (controversial, case report evidence only) 5

Reversible Causes (H's and T's)

Simultaneously search for and treat reversible causes: 3

• Hypovolemia, Hypoxia, Hydrogen ion (acidosis) 3
• Hypo/Hyperkalemia, Hypothermia 3
• Tension pneumothorax, Tamponade (cardiac) 3
• Toxins, Thrombosis (coronary or pulmonary) 3

Correct electrolyte abnormalities, particularly potassium and magnesium, to prevent recurrent VF. 1, 3

Post-ROSC Management

Once ROSC achieved:

• Discontinue antiarrhythmic infusions after 6-24 hours and reassess need 1
• Consider beta-blockers if VF occurred with acute MI 3
• Prophylactic lidocaine may be considered during EMS transport to prevent recurrent VF 1
• Insufficient evidence supports routine beta-blocker or lidocaine prophylaxis in-hospital 1
• Pursue aggressive ischemia reduction including revascularization if indicated 1, 3

Critical Pitfalls to Avoid

• Never use synchronized cardioversion for VF - always use unsynchronized shocks 3
• Do not delay first shock for CPR in witnessed arrest with defibrillator present 1, 3
• Do not perform prolonged pulse checks - if no pulse felt within 10 seconds, resume CPR 2
• Do not use AV nodal blockers (adenosine, calcium channel blockers, digoxin) in pre-excitation syndromes with rapid AF, as these can precipitate VF 3
• Do not treat isolated PVCs, couplets, or nonsustained VT - these do not require intervention 1, 3
• Do not use drop-counter infusion sets for amiodarone - use volumetric pumps only 4
• Do not exceed 2mg/mL amiodarone concentration without central venous access 4

Special Populations

For pregnant patients: Apply lateral uterine displacement to relieve aortocaval compression. 2

For suspected COVID-19: Use HEPA filters on ventilation equipment and appropriate PPE. 2

Primary VF timing: Most common (3-5% incidence) in first 4 hours after MI, declining thereafter. 1, 3