DEFIBRILLATION: LIFE-SAVING ELECTRICAL THERAPY
Defibrillation is the only effective treatment for life-threatening cardiac arrhythmias such as ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT). It involves delivering a high-energy electrical shock to reset the heart’s electrical activity, allowing for the restoration of a normal rhythm.
Why It’s Important:
Defibrillation is the most effective treatment for VF and pVT. Survival rates decrease by 7-10% per minute without defibrillation. Early defibrillation is a key component of the Chain of Survival.
HOW DEFIBRILLATION WORKS
In VF, the heart’s electrical signals become chaotic and disorganized, causing the ventricles to quiver instead of contracting effectively. In pVT, the heart beats rapidly but does not generate an effective pulse, preventing circulation. Defibrillation delivers an electrical current, which depolarizes the entire heart muscle at once, allowing the heart’s natural pacemaker (SA node) to regain control and restore a normal rhythm.
Key Takeaway: Defibrillation is the only definitive treatment for VF and pulseless VT—it must be done as quickly as possible!
WHEN TO DEFIBRILLATE: SHOCKABLE VS. NON-SHOCKABLE RHYTHMS
Defibrillation is only effective for shockable rhythms:
| Rhythm | Shockable? | Treatment |
|---|---|---|
| Ventricular Fibrillation (VF) | ✅ Yes | Immediate defibrillation |
| Pulseless Ventricular Tachycardia (pVT) | ✅ Yes | Immediate defibrillation |
| Asystole (Flatline) | ❌ No | CPR + Epinephrine |
| Pulseless Electrical Activity (PEA) | ❌ No | CPR + Treat underlying cause (Hs & Ts) |
If the rhythm is NOT shockable (Asystole or PEA), defibrillation will NOT help! CPR and medications are the main treatments in these cases.
TYPES OF DEFIBRILLATORS
1. Manual Defibrillators (Used by Healthcare Professionals)
Found in hospitals, ambulances, and advanced life support settings. Requires the rescuer to interpret the rhythm and manually select the appropriate energy level before shocking.
2. Automated External Defibrillators (AEDs)
Used in prehospital and public settings (e.g., airports, gyms, workplaces). Automatically detects and analyzes heart rhythms and advises whether a shock is needed. Designed for use by both healthcare providers and laypersons.
Key Takeaway: AEDs have made defibrillation more accessible, significantly improving out-of-hospital survival rates!
HOW TO USE AN AUTOMATED EXTERNAL DEFIBRILLATOR (AED)
Follow these steps when using an AED:
Turn on the AED – Follow the device’s voice prompts. Attach the AED pads to the victim’s bare chest (follow the pad placement diagram). Ensure no one is touching the patient and allow the AED to analyze the heart rhythm. If a shock is advised:
- Say “CLEAR!” and make sure everyone is clear.
- Press the shock button (AEDs with automatic shock delivery will do this without pressing).
Immediately resume CPR after the shock (do NOT check for a pulse yet).
Follow the AED prompts for continued resuscitation.
Key Takeaway: AEDs make defibrillation simple and effective—early defibrillation saves lives!
ENERGY LEVELS FOR DEFIBRILLATION
| Defibrillator Type | First Shock Energy | Subsequent Shocks |
|---|---|---|
| Biphasic Defibrillator (Preferred) | 120-200 J | Same or higher |
| Monophasic Defibrillator | 360 J | 360 J |
Biphasic defibrillators use two-directional currents, which require less energy and cause less heart damage than monophasic defibrillators. If using a monophasic defibrillator, always use the full 360 J for every shock.
Key Takeaway: Use the highest recommended energy setting available—underpowered shocks reduce the chance of survival.
IMPORTANCE OF EARLY DEFIBRILLATION
Time is critical – The sooner defibrillation is performed, the greater the chance of survival. Survival rates drop by 7-10% for every minute without defibrillation. If defibrillation is delayed past 10 minutes, survival is extremely unlikely.
Survival rates by time-to-shock:
| Time to Defibrillation | Chance of Survival |
|---|---|
| Within 1 minute | >90% |
| Within 3 minutes | >70% |
| Within 5 minutes | 50-60% |
| After 10 minutes | <10% |
Key Takeaway: Defibrillate as soon as possible—every second counts!
DEFIBRILLATION SAFETY MEASURES
Ensure No One is Touching the Patient Before Delivering a Shock. Remove Metallic Objects or Medication Patches Before Applying AED Pads. Avoid Water or Conductive Surfaces When Using a Defibrillator. Do NOT Place AED Pads Over Implanted Devices (e.g., Pacemakers, ICDs) – Position pads at least 1 inch away.
Key Takeaway: Always verify the environment is safe before delivering a shock!
COMMON DEFIBRILLATION MISTAKES & HOW TO AVOID THEM
| Mistake | Impact | Prevention |
|---|---|---|
| Failing to resume CPR immediately after a shock | Reduces blood flow to the brain and heart | Always restart CPR immediately! |
| Delaying defibrillation while doing CPR | Misses the critical window for shocking | Defibrillate ASAP if indicated! |
| Forgetting to check rhythm before shocking | Could shock a non-shockable rhythm | Always confirm VF/pVT before shocking! |
| Not ensuring everyone is clear before shocking | Risk of accidental shock to bystanders | Say “CLEAR!” before pressing the shock button! |
Key Takeaway: Defibrillation is only one part of resuscitation—high-quality CPR and medication support are also essential!
SUMMARY: MASTERING DEFIBRILLATION
Defibrillation is the ONLY effective treatment for VF and pulseless VT. Use an AED as soon as possible—every minute matters! Resume CPR immediately after defibrillation—do NOT pause to check for a pulse. Biphasic defibrillators require 120-200 J; monophasic requires 360 J. Never defibrillate Asystole or PEA—treat with CPR and epinephrine instead. Follow safety precautions to prevent accidental shocks.
Takeaway: Early, effective defibrillation dramatically increases survival rates—mastering its use is essential for every healthcare provider!