Defibrillation

The importance of defibrillation has been well established as part of overall resuscitation, along with effective cardiopulmonary resuscitation (CPR). An Automated External Defibrillator (AED) must only be used for persons who are unresponsive and not breathing normally. CPR must be continued until the AED is turned on and pads attached. The rescuer should then follow the AED prompts.

The time to defibrillation is a key factor that influences survival. For every minute defibrillation is delayed, there is approximately 10% reduction in survival if the victim is in cardiac arrest.

Pad Placement

Pad placement – Adults

Effective pad placement ensures that a shock is delivered on an axis through the heart. Place pads on the exposed chest in an anterior-lateral position: one pad slightly below the collar bone on the person’s right chest and one pad on the person’s left side below the arm pit (Figure 1). Acceptable alternatives are the anterior-posterior position, where one pad is placed on the upper back between the shoulder blades and the other on the front of the chest (slightly to the left, if possible); and apex-posterior.

All pads have a diagram on the outer covering demonstrating the area suitable for pad placement.

Pad to skin contact is important for successful defibrillation. Rescuers may need to remove moisture or excessive chest hair prior to the application of pads but emphasis must be on minimising delays in shock delivery.

Avoid placing pads over implantable devices. If there is an implantable medical device the defibrillator pad should be placed at least 8cm from the device. Do not place AED electrode pads directly on top of a medication patch because the patch may block delivery of energy from the electrode pad to the heart and may cause small burns to the skin. Remove medication patches and wipe the area before attaching the electrode pad.

Pad placement – Children and Infants

Standard adult AEDs and pads are suitable for use in children older than 8 years. Ideally, for those under 8 years (including infants < 1 year) paediatric pads and an AED with a paediatric capability should be used. These pads also are placed as per the adult and the pads come with a diagram of where on the chest they should be placed.

If the AED does not have a paediatric mode or paediatric pads, then it is reasonable to proceed with standard adult AED pads. Ensure the pads do not touch each other on the child’s chest.

Manual defibrillators are preferred in children. If a manual defibrillator is not available, it is appropriate to use a standard AED for children over 8 yrs.

For infants and children under 8 years, the order of preference is:

Manual Defibrillator – AED with paediatric attenuation – Standard Adult AED.

Apply the pad firmly to the bare chest in the anterior-lateral position as shown for adults in Figure 1. If the pads are too large (a particular risk in younger children and infants) and there is a danger of pad-to-pad arcing, use the front-back position (antero-posterior): one pad placed on the upper back (between the shoulder blades) and the other pad on the front of the chest, if possible, slightly to the left.

Defibrillation Sequence Chart