How is defibrillation best accomplished?
In any resuscitation, carefully check the rhythm after airway and breathing are established. Carefully confirm VF before defibrillation is attempted. Unmonitored defibrillation of a child is not recommended.
Defibrillation works by producing a mass polarization of myocardial cells with the intent of stimulating the return of a spontaneous sinus rhythm. Once VF is diagnosed, prepare the patient for defibrillation and correct acidosis and hypoxemia. High-amplitude (coarse) fibrillation is more easily reversed than low-amplitude (fine) fibrillation. Administration of epinephrine can help coarsen fibrillation.
Defibrillation is most effective with use of the largest paddle that makes complete contact with the chest wall. Using the larger (8-cm diameter) paddle lowers the intrathoracic impedance and increases the effectiveness of the defibrillation current.
Take care to use an appropriate interface between the paddles and the chest wall. Electrode cream, paste, or gel pads are preferred when using paddles. Do not use saline-soaked gauze pads, ultrasound gel, alcohol pads, or bare paddles. Whenever available and if time allows, place and use self-adhesive defibrillation pads instead of paddles, as they allow for safer and more efficient shock delivery and then can be used for cardiac pacing when appropriate.
Whether gel, paste, or pads are used, placement must be meticulous, because electrical bridging across the surface of the chest results in ineffective defibrillation and, possibly, skin burns. When attempting defibrillation, immediate CPR should follow the delivery of one shock, rather than delivery of up to three shocks before CPR. This recommendation is based on the fact that the first shock eliminates VF 85% of the time, and studies have shown long delays typically occur between shocks when automated external defibrillators (AEDs) are used.
For defibrillation of the pediatric patient use an initial dose of 2 to 4 J/kg.
American Heart Association: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations. Part 10: Pediatric Basic and Advanced Life Support. Circulation 2010;122:S466-S515.