⚡ Chapter 134: Defibrillation and Cardioversion

Defibrillation (non-synchronized) · Cardioversion (synchronized) · Energy doses (2-4 J/kg defib, 0.5-2 J/kg cardiovert) · Biphasic vs monophasic · AED · Paddle placement · Complications

🔍 Core Concepts: Defibrillation & Cardioversion

📌 Defibrillation vs Cardioversion
Defibrillation: non-synchronized, used for pulseless VT/VF. Cardioversion: synchronized to R wave, used for SVT, VT with pulse, atrial flutter/fibrillation.
⚡ Energy Doses (Children)
Defibrillation: 2 J/kg first shock, then 4 J/kg, max 10 J/kg. Cardioversion: 0.5-1 J/kg initial, increase to 2 J/kg if needed (max 4 J/kg).
🩺 Paddle/Pad Placement
Anterior-lateral (right sternal border, left midaxillary) or anterior-posterior (sternum + back). Anterior-posterior preferred for cardioversion.
🔄 Synchronized Mode
Sync button ON – shock delivered on R wave. Confirm marker on QRS. Never use sync mode for pulseless VF/VT.
🛡️ Safety & Technique
Ensure all personnel clear, no oxygen near paddles, firm pressure (12 kg/paddle), conductive gel, no gel bridging between paddles.
📊 Biphasic vs Monophasic
Biphasic waveforms require lower energy, cause less myocardial injury, higher first-shock success. Modern defibrillators are biphasic.
⚠️ Complications
Burns, thromboembolism, arrhythmias, myocardial injury. Risk reduced with correct energy, gel, and paddle pressure.

⚡ Stepwise Approach to Defibrillation & Cardioversion

1
Identify rhythm and patient stability
Pulseless VT/VF → defibrillation (non-synchronized). SVT/VT with pulse → synchronised cardioversion (if unstable) or pharmacologic if stable.
2
Prepare equipment & patient
Turn on defibrillator. Apply conductive gel/pads. Place paddles in anterior-lateral or anterior-posterior position. Ensure no oxygen near paddles.
3
Select energy & mode
Defib: 2 J/kg, sync OFF. Cardioversion: 0.5-1 J/kg, sync ON (verify R-wave marker). Charge defibrillator.
4
Clear & deliver shock
Shout “Clear!” – ensure no one touching patient, bed, or oxygen. Apply firm pressure (~12 kg per paddle). Press both discharge buttons simultaneously.
5
Post-shock management
Immediately resume CPR (for cardiac arrest) for 2 minutes before rechecking rhythm. For cardioversion, check ECG and blood pressure. If unsuccessful, double energy (defib: 4 J/kg; cardioversion: 2 J/kg) and repeat.