Defibrillation is a medical procedure that delivers a controlled electrical shock to the heart to interrupt abnormal rhythms and allow the heart’s natural pacemaker to regain control. It is used for life-threatening cardiac arrhythmias, specifically ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT). The goal of defibrillation is to depolarize a significant portion of the heart muscle, effectively resetting its electrical activity. This process aims to restore a normal, effective heart rhythm.
Unique Aspects of Infant Defibrillation
Infant physiology presents distinct considerations for defibrillation compared to adults or older children. Cardiac arrest in infants (under one year of age) is often caused by respiratory issues leading to bradycardia, or a slow heart rate, which can then progress to asystole, where the heart stops completely. This differs from adults, where ventricular fibrillation is a more common initial rhythm.
The smaller chest size and developing organs of infants necessitate precise control over the energy delivered during defibrillation. Their smaller body mass means that even a standard adult shock could deliver an excessively high dose per kilogram, potentially causing harm to the delicate myocardial tissue. The electrical resistance across an infant’s chest is also lower than an adult’s, making precise energy titration even more important to prevent injury.
Manual Defibrillation for Infants
Manual defibrillators offer healthcare professionals direct control over the energy dose delivered, which is a significant advantage in infant cardiac emergencies. Operators can precisely set the energy level in joules, typically based on the infant’s weight. This customization allows for titration of the energy to achieve successful rhythm conversion while minimizing potential harm. Manual defibrillators also allow for continuous monitoring of the infant’s heart rhythm, enabling trained personnel to assess the effectiveness of the shock and make informed decisions.
The use of appropriately sized paddles or pads is another important aspect of manual defibrillation for infants. Smaller pads ensure proper contact with the infant’s chest without touching each other, which helps deliver the electrical current effectively across the heart. The precision and flexibility offered by manual devices require a high level of operator skill and training in advanced cardiac life support.
Automated External Defibrillator Use in Infants
Automated External Defibrillators (AEDs) are designed for ease of use, automatically analyzing heart rhythms and delivering a shock. Standard AEDs, however, are primarily configured for adult patients and deliver a fixed, higher energy dose. Using an adult AED on an infant without modification can deliver an energy level potentially causing myocardial damage.
To address this, pediatric attenuated pads or keys are available for many AEDs. These specialized pads reduce the energy output of the AED to a level more appropriate for infants and young children, typically around 50 joules. Even with attenuation, AEDs deliver a pre-set, fixed energy dose, which lacks the precise, titratable control offered by manual defibrillators. While AEDs can be used safely in infants with these modifications, the inability to fine-tune the energy level can be a limitation.
Current Medical Guidelines
Major resuscitation organizations, such as the American Heart Association (AHA) and the International Liaison Committee on Resuscitation (ILCOR), provide specific guidelines for infant defibrillation. These guidelines recommend that manual defibrillators are preferred for infants less than one year of age when available.
For manual defibrillation in infants, the recommended initial energy dose is 2 joules per kilogram (J/kg), with subsequent shocks potentially escalating to 4 J/kg. If a manual defibrillator is not immediately available, an AED equipped with pediatric attenuated pads or a pediatric key is an acceptable alternative. These attenuated devices reduce the shock energy to a safer level for infants. Should only adult pads be available, they can still be used on infants by placing one pad on the front of the chest and one on the back to ensure they do not touch.