ACLS Provider: Course

Defibrillation and AED Use in Clinical Settings

Defibrillation is a cornerstone of advanced resuscitative care. It is the only definitive treatment for life-threatening arrhythmias like ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT). When performed early and effectively, defibrillation significantly increases the likelihood of return of spontaneous circulation (ROSC) and survival with good neurological outcomes. This lesson covers the principles of defibrillation, shockable rhythm recognition, and the practical use of automated external defibrillators (AEDs) in clinical and emergency settings.

Shockable vs. Non-Shockable Rhythms

Before delivering a shock, it's essential to identify whether the patient is experiencing a rhythm that can benefit from defibrillation.

  • Shockable: Ventricular fibrillation (VF), Pulseless ventricular tachycardia (pVT)
  • Non-shockable: Asystole, Pulseless electrical activity (PEA)

Attempting defibrillation on non-shockable rhythms is ineffective and delays critical interventions like CPR and medication administration.

Types of Defibrillators

  • Manual Defibrillators: Used by ACLS-trained providers to interpret rhythms and set energy levels manually.
  • Automated External Defibrillators (AEDs): Analyze the rhythm automatically and prompt the user to deliver a shock if needed. Ideal for rapid use in both clinical and public settings.

Steps for Using an AED

  1. Turn on the AED and follow the voice prompts.
  2. Expose the chest and apply AED pads in the correct position (upper right chest and lower left side).
  3. Ensure no one is touching the patient while rhythm analysis occurs.
  4. If advised, say “CLEAR,” then press the shock button.
  5. Immediately resume CPR for two minutes before reassessing rhythm.

Energy Settings

  • Biphasic defibrillators: 120–200 joules (follow device-specific recommendation).
  • Monophasic defibrillators: Always 360 joules.

Timing and Survival

Every minute defibrillation is delayed reduces survival by 7–10%. Early defibrillation, ideally within the first few minutes of arrest, is critical.

  • <1 minute: >90% survival chance
  • 3–5 minutes: 50–70%
  • >10 minutes: <10% survival

Defibrillation Safety Tips

  • Ensure no one is in contact with the patient during shock delivery.
  • Avoid water or wet surfaces. Dry the chest if needed.
  • Remove medication patches or metal objects from pad sites.
  • Place pads at least 1 inch away from implanted devices like pacemakers or ICDs.

Common Errors and How to Avoid Them

  • Failing to resume CPR immediately after the shock: Always continue compressions right after delivering a shock.
  • Delaying defibrillation: Prioritize shocking over prolonged pulse checks or extended CPR intervals.
  • Shocking a non-shockable rhythm: Always confirm VF or pVT before pressing the shock button.

Key Takeaways

  • Defibrillation is the definitive treatment for VF and pVT.
  • Use an AED or manual defibrillator as early as possible.
  • Resume CPR immediately after shock—do not pause to check for a pulse.
  • Know the energy settings for your defibrillator type and follow safety protocols to prevent harm to rescuers and patients.