When someone's heart stops beating due to either a cardiac arrhythmia, ventricular fibrillation, or ventricular tachycardia, a defibrillator device can be used to restart the heart. The most common form of defibrillator, the Automatic External Defibrillator (AED) uses different types of defibrillator pads to adjust the voltage delivered to the heart. The defibrillator itself produces only one type of shock at the highest joule setting. The purpose of the pads is to reduce the joules to the appropriate level.
There are three main types of defibrillator: manual external, manual internal, and automatic external. The only type that an untrained civilian is allowed to use is the automatic external, since the other two require extensive training in order to be used safely. The reason that AED's are safe for use by non-professionals is that they are purposefully built to walk the user through using the device, as well as performing all the necessary calculations.
The first type of defibrillator pads are standard, or adult, size pads. These pads are used on larger humans, typically aged ten and up. Defibrillator pad usage is not determined by age, but overall body size and mass. Adult defibrillator pads are placed sticky side down over the victim's right lung area, as well as the left side of the ribcage, about six inches below the armpit. Adult defibrillator pads are often colored blue, but this varies between manufacturers.
Children's defibrillator pads are used on small children over age one. Children's pads are used much like the adult pads and are placed sticky side down on the chest and back of the child. The pads should be placed in the middle of the chest/back, about six inches below the neck. Children's defibrillator pads are often colored pink or yellow, although this is not always the case.
There are a few special circumstances that may arise while using an AED that must be dealt with properly. If the victim is pregnant, place the pads as far away from the fetus as possible, while keeping the AED effective. If the victim is covered in water, or is lying in water, move them to a dry area and wipe all of the water from their chest before attaching the pads. If the victim is especially hairy preventing the defibrillator pads from properly contacting the skin, use a razor to remove the hair. If no razor is available, the second set of pads can be used to “wax” the hair off of the placement area using the sticky side.