双相方波除颤技术ppt课件.ppt

* Finally, we need to examine the reported data in light of an AHA Scientific Statement. In 1997, the AHA’s Emergency Cardiac Care Committee published a statement that, in part, described a process for validating “alternative” defibrillation waveforms. In it, they described thresholds for equivalent and superior performance. Whereas the data published on BTE waveforms has achieved the equivalent threshold, only the data reported for the RBW technology crosses the threshold for superiority. * While on the subject of the AHA, it is important to note that the most recent Guidelines for Resuscitation address biphasic defibrillation. Specifically, they define biphasic defibrillation as safe and effective at less than or equal to 200 joules. It is important to note, that in the absence on any high energy data, the AHA does not address shocks over 200 joules. Importantly, the Guidelines tell us biphasic protocols are waveform specific. That is, they need to be used in light of data from peer-reviewed, randomized trials. And finally they give low-energy biphasic defibrillation a Class IIa recommendation, the same classification as conventional monophasic defibrillation. * These findings show us the influence of waveform shape on defibrillation efficacy. The horizontal axis presents six 10 millisecond waveforms. At the left, labeled “10M,” is a monophasic waveform. The remainder are differing biphasic waveforms. The vertical axis depicts the threshold of defibrillation (DFT). (On this graph, a lower value means it is easier to defibrillate). This study tells us two things: 1) As the shape of a biphasic waveform changes, so does its threshold for defibrillation (DFT). This has a direct bearing on clinical performance in that a lower DFT translates into higher efficacy at lower currents and energies. 2) Some biphasic waveforms, as illustrated by the second (2.5-7.5) and third (3.5-6.5) from the left, don’t work as well as monophasic waveforms. * These findings show us the