Defibrillation is a medical procedure that delivers a controlled electrical shock to the heart, aiming to restore a normal rhythm during sudden cardiac arrest. This intervention is particularly effective for life-threatening abnormal heart rhythms, such as ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT), where the heart’s electrical activity becomes chaotic. Early defibrillation significantly increases the chances of survival, as the probability of survival decreases by about 7% to 10% for every minute without it. Treating children, however, requires distinct considerations because they are not simply small adults.
Why Young Children Require a Different Approach
Children possess unique physiological characteristics that necessitate a different approach to defibrillation compared to adults. Their smaller body size and developing organ systems mean their bodies respond differently to electrical currents. Cardiac arrest in children is often a secondary event, commonly resulting from respiratory failure or shock, rather than a primary cardiac issue as frequently seen in adults. This underlying cause impacts the overall resuscitation strategy.
A child’s heart also responds differently to defibrillation. Their hearts are proportionally larger relative to their body size, yet they have less efficient contractile function. Therefore, the energy delivered must be carefully calibrated to be effective without causing harm to the delicate myocardial tissue.
Specific Adjustments for Defibrillation in Children
The energy level used is considerably lower than for adults and is often calculated based on the child’s body weight. An initial dose of 2 to 4 joules per kilogram (J/kg) of body weight is recommended, with subsequent shocks potentially escalating to at least 4 J/kg, not exceeding 10 J/kg or the adult maximum dose. This weight-based dosing helps deliver an appropriate amount of energy for the child’s smaller cardiac mass.
The size of the defibrillation pads is also important. Pediatric-sized pads are designed for children under 8 years of age or those weighing less than approximately 25 kilograms (55 pounds). These smaller pads prevent them from touching each other on the child’s chest, which could lead to an ineffective shock. If pediatric pads are unavailable, adult pads can be used, provided they do not overlap.
Pad placement on a child often differs from the standard adult anterior-lateral (front-side) placement. For children, particularly infants, an anterior-posterior (front-back) pad placement is preferred. One pad is placed on the front of the chest, and the other is placed on the back, ensuring the heart is effectively positioned within the electrical pathway. This technique ensures optimal current delivery across the chest cavity.
Using an Automated External Defibrillator (AED) on a Child
Many Automated External Defibrillators (AEDs) include features specifically for pediatric use. These devices often have pediatric attenuator keys or pads that reduce the energy output to a level appropriate for a child. Some newer AEDs feature a “child mode” button that adjusts the energy settings when activated.
When using an AED on a child, it is important to first expose the chest and wipe it dry if necessary. If pediatric pads or a child mode setting are available, they should be used, with pads placed firmly on the child’s bare skin, ideally in an anterior-posterior configuration. The AED will then provide clear voice prompts, guiding the rescuer through rhythm analysis and shock delivery. If pediatric-specific equipment is not available, adult pads can still be used on a child, ensuring they are placed so they do not touch each other, often in the anterior-posterior position.
Safety and When to Seek Immediate Medical Help
Before delivering a shock, it is crucial to ensure that no one is touching the child or any conductive surfaces connected to them. The AED will issue a “clear” warning before delivering the shock, and all bystanders should verbalize “clear” and step away.
Immediately calling emergency medical services (EMS) is the first step when a child collapses or is unresponsive. Defibrillation is only one component of an emergency response, and professional medical care is always required. While waiting for EMS and an AED to arrive, high-quality cardiopulmonary resuscitation (CPR) should be initiated and continued without interruption. CPR helps maintain blood flow to organs until defibrillation can occur, improving the child’s chances of survival.