An Automated External Defibrillator (AED) is a portable device designed to deliver an electrical shock to the heart, interrupting a life-threatening abnormal heart rhythm. While AEDs are commonly associated with adult cardiac arrest, they can be safely and effectively used on infants, but only with specific technical modifications. The standard adult energy setting is too powerful, requiring specialized equipment to reduce the electrical dosage and ensure proper application.
Context for Infant Cardiac Arrest
For defibrillation purposes, an infant is typically defined as a child under one year of age, though guidelines often group them with children under eight years old or weighing less than 55 pounds. The cause of cardiac arrest in infants differs significantly from adults, influencing the initial resuscitation approach. Adult cardiac arrest is usually a primary electrical problem, resulting in a sudden, shockable rhythm.
Infant cardiac arrest is far more likely to be secondary to respiratory failure, shock, or asphyxia, meaning the heart stops due to lack of oxygen rather than a primary electrical malfunction. This distinction makes initial high-quality cardiopulmonary resuscitation (CPR) paramount in infant emergencies. Rescuers should perform approximately two minutes of CPR, focusing on chest compressions and rescue breaths, before attaching the AED.
This initial CPR period helps re-oxygenate the blood, which may resolve the problem without a shock. If the cardiac arrest was witnessed and sudden, indicating a primary electrical issue, the AED should be applied immediately. While the primary presentation for infants is usually a non-shockable rhythm, the AED is still used to analyze the rhythm and guide the resuscitation effort.
Required Specialized Equipment and Settings
Using an AED on an infant requires specialized modifications to ensure the delivered electrical energy is appropriately attenuated for their small body size. Standard adult AEDs deliver a high-energy shock (150 to 360 Joules), which is unsafe for an infant’s developing heart and tissues. Specialized pediatric equipment reduces this dose significantly, usually to a range of 50 to 75 Joules, about one-third of the adult energy output.
This dose reduction, known as attenuation, is achieved either through dedicated Child/Pediatric Attenuator Pads or by inserting a special key or activating a switch on the AED unit. The attenuator pads contain a resistor circuit that lowers the energy delivered from the AED. These pads are also smaller than adult pads, ensuring they do not touch when placed on the infant’s chest, which would short-circuit the electrical current.
Proper pad placement is critical for infants due to their size. Instead of the standard adult placement (upper right chest and lower left ribcage, or anterolateral), infant pads must be placed in an anterior-posterior configuration. This involves placing one pad on the center of the chest, over the breastbone, and the second pad on the back, between the shoulder blades. This ensures the electrical current passes effectively through the heart muscle without the pads touching.
Step-by-Step Application Guidelines
The application of an AED on an infant follows a distinct sequence after the initial two minutes of CPR, or immediately if the collapse was sudden and witnessed. The first step is to power on the Automated External Defibrillator, which immediately provides voice prompts to guide the rescuer. Next, the appropriate specialized pediatric pads or the attenuator key must be connected or activated.
The rescuer must expose the infant’s chest and attach the pediatric pads in the anterior-posterior position, ensuring the skin is dry. Once the pads are securely connected to the infant and plugged into the AED unit, the device prompts everyone to stand clear while it analyzes the heart’s electrical rhythm. No one should touch the infant during this analysis phase.
If the AED determines a shockable rhythm, it charges and advises the rescuer to deliver a controlled shock, often requiring the rescuer to press a flashing button while announcing, “Clear!” If a shock is delivered, CPR must be immediately resumed, starting with chest compressions, without waiting to re-analyze the rhythm. The rescuer continues with two minutes of high-quality CPR before the AED re-analyzes the rhythm and delivers further prompts.