What are the steps for defibrillation in a patient with ventricular fibrillation or pulseless ventricular tachycardia?

Defibrillation Steps for Ventricular Fibrillation or Pulseless Ventricular Tachycardia

Early defibrillation with concurrent high-quality CPR is critical to survival when sudden cardiac arrest is caused by ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). 1

Initial Assessment and Preparation

• Confirm cardiac arrest by checking for responsiveness and absence of normal breathing 1
• Immediately begin high-quality CPR with chest compressions at a rate of at least 100/minute and a depth of at least 2 inches (5 cm) 1
• Attach monitor/defibrillator as soon as possible while minimizing interruptions to chest compressions 2
• Identify VF/pulseless VT on the monitor (disorganized electrical activity without discernible QRS complexes) 2

Defibrillation Protocol

• For witnessed VF/VT arrest, deliver an immediate unsynchronized shock 1, 2
• For unwitnessed arrest, consider 2 minutes of CPR before the first shock 1, 2
• Use appropriate energy settings:
  • For biphasic defibrillators: use manufacturer's recommended dose (typically 120-200J) 2
  • For monophasic defibrillators: use 360J 1, 2
• Resume CPR immediately after each shock, beginning with chest compressions 1
• Minimize interruptions in chest compressions, including during rhythm analysis 1
• After 2 minutes of CPR, reassess rhythm and deliver another shock if VF/VT persists 1

Medication Administration

• Establish IV/IO access while continuing CPR 2
• After the first shock and resumption of CPR, administer epinephrine 1mg IV/IO 2
• Repeat epinephrine every 3-5 minutes during cardiac arrest 2
• After the second shock and resumption of CPR, consider administering:
  • Amiodarone 300mg IV/IO bolus 3
  • If amiodarone is unavailable, consider lidocaine 1.5mg/kg IV/IO 2
• For persistent VF/VT, consider a second dose of amiodarone 150mg IV/IO after 3-5 minutes 3

Advanced Airway Management

• Consider advanced airway placement after initial shocks if personnel are available 2
• If an advanced airway is placed, deliver 1 breath every 6 seconds (10 breaths/min) with continuous chest compressions 1
• Use waveform capnography to confirm and monitor endotracheal tube placement 2

Ongoing Management

• Continue the cycle of CPR-rhythm check-shock (if indicated)-CPR-medications 1
• Minimize interruptions in chest compressions to less than 10 seconds 1
• Consider potential reversible causes (Hs and Ts): Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo/hyperkalemia, Hypothermia, Tension pneumothorax, Tamponade, Toxins, Thrombosis 2

Post-Resuscitation Care (if ROSC achieved)

• Maintain adequate ventilation and oxygenation 2
• Consider targeted temperature management for patients who do not follow commands after ROSC 1
• Correct electrolyte abnormalities, particularly potassium and magnesium 2
• Perform 12-lead ECG and consider cardiac catheterization if indicated 1

Common Pitfalls to Avoid

• Do not delay defibrillation for witnessed VF/VT arrest 1
• Avoid excessive interruptions in chest compressions, including for rhythm checks 1
• Never use synchronized cardioversion for VF (always use unsynchronized shocks) 2
• Avoid excessive ventilation, which can decrease cardiac output during CPR 2
• Monitor for potential adverse effects of amiodarone, including hypotension, bradycardia, and hepatic injury 3