External defibrillation: new technologies.

Recent technological advances have enhanced our ability to diagnose and treat ventricular fibrillation (VF). Self-adhesive electrode pads for external defibrillation are as effective as standard hand-held paddle electrodes, and have substantial advantages for monitoring during transportation and in the emergency department/intensive care unit/critical care unit. These electrode pads work equally well whether placed in apex-anterior or apex-posterior positions. Preapplication in calm, prearrest circumstances assures accurate placement and enhances shock success. Transthoracic impedance is a critical determinant of the success of low-energy shocks. Prediction of transthoracic impedance in advance of the first shock is now feasible. First-shock energy can then be based on impedance, and inappropriate low energies for high-impedance patients may be avoided. Automatic external defibrillation by minimally trained rescuers extends our ability to treat out-of-hospital ventricular fibrillation. A vertical defibrillation pathway, using the tongue as one electrode site, allows rapid, automated detection of VF. Animal defibrillation studies and preliminary human studies (during elective cardioversion) have demonstrated the efficacy of the pathway and defined the impedance and energy requirements. Clinical trials of the device for out-of-hospital defibrillation are now in progress.