Manual Defibrillation

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This module describes how to perform manual defibrillation as part of cardiopulmonary resuscitation.


  1. Cardiac arrest with “shockable” heart rhythms:

  2. Ventricular fibrillation

  3. Pulseless ventricular tachycardia


  1. Patients not in cardiac arrest

  2. Patients in cardiac arrest with unshockable rhythms (pulseless electrical activity or asystole)—continue with chest compressions


This procedure is done when a patient is in cardiac arrest, so consent is generally implied. However, check for “Do Not Resuscitate” (DNR) orders, “Not For Max” orders, or living wills that specify that no resuscitation may be performed.


Manual defibrillation is an emergency procedure. Always:

  1. Know where defibrillators, transcutaneous pads, and red trolleys are kept. Know the relevant staff and keep your seniors’ contact details close at hand.

  2. Familiarise yourself with the defibrillators in your work area. Check that they are maintained regularly and have pads and the correct connections.

  3. Keep unstable patients in resuscitation bays with continuous monitoring.


To perform manual defibrillation, a patient should be lying flat on their back on a firm surface with their chest exposed. All clothes, including undergarments, should be removed from the chest.


Follow medical asepsis with non-sterile gloves. Do not interrupt chest compressions until completely necessary. This procedure is a part of basic or advanced cardiac life support. The description below assumes that the patient is

to ECG monitoring.

Defibrillator with paddles:

  1. Switch On the defibrillator to

    mode.

  2. If the defibrillator is not already on Paddles mode, press the Lead select button until it shows Paddles.

  3. Face the machine. Lift the paddles and ask an assistant to apply conductive gel to the paddles.

  4. Place the paddles on the chest, the paddle in your left hand at the right second intercostal space, and the paddle in your right hand on the left midaxillary line near the apex of the heart.

  5. Look at the defibrillator screen to analyse the rhythm. If you find an unshockable rhythm, return the paddles and continue with another cycle of CPR. If you find a shockable rhythm, defibrillate following steps 6 to 10.

  6. Ask an assistant to dial the Energy up to the required level (120-200 for biphasic machines and 360 for monophasic; or 2 joules per kg in children).

  7. Using your thumb, press the

    button and call out, “Charging!”

  8. While charging, call out, “I’m clear, you’re clear, oxygen clear!”, ensuring that nobody is touching the patient and that all oxygen delivery devices are well away from the patient.

  9. Call out, “Shocking!” and press both index fingers on the Shock buttons on the paddles.

  10. Call out, “Shock delivered!”, and allow chest compressions to resume immediately. Do not pause or delay chess compressions to analyse directly after defibrillation. Return the paddles to the defibrillator.

  11. During chest compressions, attach the three monitoring leads to the patient’s chest and switch to Lead II lead select mode.

  12. After every 2 minutes (or 5 cycles) of CPR, analyse the rhythm while checking for a pulse and

    again if required, repeating steps 6-10. See Advanced Cardiac Life Support for further considerations.

Defibrillator with pads:

  1. Apply pads to the chest as directed on packaging.

  2. Switch to Manual Defibrillation mode and follow the steps as outlined above.

  3. Monitoring in-between shocks occurs through the pads.


The patient has a lot of breast tissue.

Always try to place pads under or lateral to breasts. Large breasts can compromise the effectiveness of the shock delivered.

My patient is soaking wet.

Wipe the patient down quickly before applying pads.

My patient is so hairy I can’t get contact with the skin.

Use a razor to shave the contact areas, or use any kind of adhesive dressing or pads to “wax” off the worst of the body hair.

My patient is wearing an underwire bra.

Cut it off. The current can run through the underwires, rendering it ineffective, and can cause burns.

My patient has a medication patch on their chest.

Remove it and wipe the area quickly.

My patient has an implanted pacemaker or defibrillator.

Don’t be deterred, but avoid placing your paddles on the device.

The screen keeps showing asystole.

Press the Gain button several times to enlarge the ECG displayed. You may have a very low amplitude rhythm you just can’t see at the current level of gain.

Where do I place the three leads?

“Red on the right, green on the spleen, and what’s left on the left.” Place the red electrode on the right shoulder, yellow electrode on the left shoulder, and green electrode on the lower left torso.

I’ve charged, but I decided I don’t need to shock.

Ask an assistant to turn the defibrillator to Monitor instead of Defibrillation. This safely dumps the charge. Do not move charged paddles from the patient’s chest.

How do I keep myself and my colleagues safe from electrical accidents?

Always shout “Clear!” before shocking.

Always keep oxygen sources at least an arm’s length away (oxygen + electricity can cause explosions).

Paddles should always be firmly on the patient’s chest, or placed in their rests on the machine. Don’t put paddles down anywhere else.

Never hold both paddles in one hand.


  1. Rhythm conversion to an unshockable rhythm

  2. Burns & electrical injuries to patient

  3. Burns & electrical injuries to healthcare providers

  4. Explosions and medical fires due to oxygen exposure


  1. O’Connor RE. Cardiopulmonary Resuscitation (CPR) in Adults. In: Merck Manual Professional Version. 2019. Available from: https://www.merckmanuals.com/professional/critical-care-medicine/cardiac-arrest-and-cpr/cardiopulmonary-resuscitation-cpr-in-adults