Electrical defibrillation: new technologies.
Two-thirds of deaths from coronary disease occur in the pre-hospital phase and are caused by ventricular fibrillation or pulseless ventricular tachycardia, for which electrical defibrillation is the only effective treatment. The time delay between the onset of ventricular fibrillation and the administration of the first defibrillatory shock is the most important determinant for survival. To achieve the earliest defibrillation possible, rescuers others than physicians need to be able to initiate this treatment. The international scientific community strongly supports the concept of early defibrillation in the setting of a strong chain of survival. New technological developments of automated external defibrillators (AEDs) allowed the implementation of defibrillation by the first responding professional rescuer. As a consequence of the technological evolution in implantable defibrillators, much research has also been done on new defibrillation waveforms and alternative energy levels in external defibrillators. After initial animal research, human clinical investigation has shown that initial low energy (150J) nonprogressive (150J-150J-150J) impedance-adjusted biphasic waveform defibrillatory shocks for patients in out-of-hospital ventricular fibrillation are safe, acceptable and clinically effective. Reporting on outcome from cardiac arrest must be as uniform as possible to allow conclusions on performance of emergency medical service systems. The 'Utstein Style' nomenclature is a glossary of terms and a reporting guideline for uniform description of cardiac arrest, resuscitation, the emergency medical service (EMS) system and the outcome. Reports on experiences with AED programmes by traditional and non-traditional professional rescuers support the view that AEDs should not be implemented in EMS systems as an isolated intervention, but that efforts are equally needed to strengthen the other links of the chain of survival. The international scientific community (American Heart Association, International Liaison Committee on Resuscitation and European Resuscitation Council) have issued guidelines for the use of AEDs by EMS providers and first responders, and a universal treatment algorithm is proposed.
Bossaert
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Critical Care Department, University Hospital Antwerp, B2650 Edegem-Antwerp, Belgium. bossaert@uia.ua.ac.be