Automated external defibrillators (AED’s) have been widely used on children and infants for decades. They have the potential to reverse the process of Ventricular Fibrillation (VT), and so can restart a child's heart during cardiac arrest.

Use in children and infants is slightly complicated due to their size and age. The adult AED could deliver too great a shock and may have inappropriate pads for the child's size. In light of this there are some simple steps to consider when using an AED on a child.


The aim of pad placement regardless of age is to position the pads so that they deliver a shock right through the heart. This can be achieved with smaller paediatric pads being placed in the positions as illustrated above on the child. These specialist pads are designed for children & infants under 8 years of age.

It is important that the pads do not touch each other as this could interfere with the transmission of the shock. Very small children and infants would need one pad over the heart and the other directly opposite on the back (as illustrated in the first diagram).


The pads attach to the AED computer which utilizes data within a database to make decisions based on shock and frequency. Depending on the model / manufacturer, a key may need to be turned on the AED unit when treating the child casualty.

A child's heart beats faster than an adults and will require less energy during a shock. Having different paediatric pads is useful because the computer will detect the differences and respond accordingly.

Helpful hint - When no paediatric pads are available the adult pads can be placed on a child of 8 years old or above.


Adult dosages of energy from the AED equate to roughly 2J/kg. Therefore an average adult of 70 Kg would require a shock of 140 J. The child has a lower dosage (2J/Kg) with the potential to rise to 4J/Kg) when necessary. Therefore an average 20 Kg child would require a shock of around 40 - 80 J.

The question that often gets asked is how many volts does this equate to?

The problem is that Joules and Watts do not correlate very well. The energy coming out of the machine needs to be measured and this measurement is made in joules. However, as a guideline, the machine has enough electrical output (watts) to place a live casualty into cardiac arrest. Fortunately the machine's safety mechanisms would never allow this to happen.

Remember - The machine's user friendly nature means the end user only has to place the pads and follow the voice prompts. The machine calculates the dosage itself.