ABSTRACT
<p><b>INTRODUCTION</b>Peak currents are the final arbiter of defibrillation in patients with ventricular fibrillation (VF). However, biphasic defibrillators continue to use energy in joules for electrical conversion in hopes that their impedance compensation properties will address transthoracic impedance (TTI), which must be overcome when a fixed amount of energy is delivered. However, optimal peak currents for conversion of VF remain unclear. We aimed to determine the role of peak current and optimal peak levels for conversion in collapsed VF patients.</p><p><b>METHODS</b>Adult, non-pregnant patients presenting with non-traumatic VF were included in the study. All defibrillations that occurred were included. Impedance values during defibrillation were used to calculate peak current values. The endpoint was return of spontaneous circulation (ROSC).</p><p><b>RESULTS</b>Of the 197 patients analysed, 105 had ROSC. Characteristics of patients with and without ROSC were comparable. Short duration of collapse < 10 minutes correlated positively with ROSC. Generally, patients with average or high TTI converted at lower peak currents. 25% of patients with high TTI converted at 13.3 ± 2.3 A, 22.7% with average TTI at 18.2 ± 2.5 A and 18.6% with low TTI at 27.0 ± 4.7 A (p = 0.729). Highest peak current conversions were at < 15 A and 15-20 A. Of the 44 patients who achieved first-shock ROSC, 33 (75.0%) received < 20 A peak current vs. > 20 A for the remaining 11 (25%) patients (p = 0.002).</p><p><b>CONCLUSION</b>For best effect, priming biphasic defibrillators to deliver specific peak currents should be considered.</p>
ABSTRACT
Objective To explore the application of defibrillation energy measurement and result uncertainty assessment to defibrillator quality control.Methods The released energy of the defibrillator was measured in standardized technology and environmental conditions,and uncertainty assessment was carried out according to the criteria JJF 1059-2012 Assessment and expression of measurement uncertainty,and then the quality of the defibrillator was executed based on uncertainty.Results Uncertainty assessment contributed to the evaluation of the defibrillator quality,and provided guidance to medical engineering departments in the defibrillator quality control.Conclusion Uncertainty assessment of the defibrillation energy measurement facilitates the quality control,and thus can be promoted in the quality control of other likely medical devices such as respirator,infusion pump and electrosphygmomanometer.
ABSTRACT
Objective To explore the application of defibrillation energy measurement and result uncertainty assessment to defibrillator quality control.Methods The released energy of the defibrillator was measured in standardized technology and environmental conditions,and uncertainty assessment was carried out according to the criteria JJF 1059-2012 Assessment and expression of measurement uncertainty,and then the quality of the defibrillator was executed based on uncertainty.Results Uncertainty assessment contributed to the evaluation of the defibrillator quality,and provided guidance to medical engineering departments in the defibrillator quality control.Conclusion Uncertainty assessment of the defibrillation energy measurement facilitates the quality control,and thus can be promoted in the quality control of other likely medical devices such as respirator,infusion pump and electrosphygmomanometer.
ABSTRACT
To develop a standard defibrillation energy source which can output monophasic and biphasic de-fibrillation impulses and can display standard energy values. The storage capacitor was charged by single-end flyback transformator and discharged through the H bridge composed of insulated gate bipolar transistor (IGBT). Impulse voltage and current were collected by divider while discharging, and the energy value was calculated by STM32. The en-ergy value and waveform were displayed through the control module. The energy source could output both monophsic and biphasic waveforms, and the accuracy of displayed value was higher than ±2% or ±1 J. The standard defibrillation energy source can be used as standard device for defibrillator analyzer, and the metrological trace-ability system of defibrillation energy may come to be completed.
ABSTRACT
Objective Amiodarone was diluted to release the side effect of hypotension in clinic, but this maybe unsuitable during cardiopulmonary resuscitation (CPR). This study was designed to observe the effects of undiluted amiodarone, diluted amiodarone, and CPR alone on ventricular fibrillation (VF) in a pig model. MethodsVF was induced in 21 pigs. The animals were randomly (random mumber) divided into 3 groups after VF 3 min.① CPR group ( n= 7): standard CPR; ② undiluted amiodarone group ( n= 7): undiluted amiodarone (5 mg/kg)bolus within 3 s, then 20 mL saline flush into the peripheral vein, CPR was started after observed 30 s; ③ diluted amiodarone group ( n = 7): amiodarone was dissolved in 20 mL saline and bolus with 30 s. Defibrillation was attempted at VF 5 min. Results The restoration of spontaneous circulation (ROSC) of CPR and undiluted amiodarone groups were higher than diluted group (85.7％ vs. 71.4％ vs. 42.9％), but the differences were not significant (all P ＞0.05). The defibrillation energy and timesof CPR group were higher than that of undiluted amiodarone (P= 0.009) and diluted group ( P = 0. 170). The mean arterial pressure of undiluted amiodarone were lower than diluted and CPR groups at ROSC 10 min (all P ＜0.05), but the differences of undiluted and diluted groups were not significant after ROSC 0.5 h. Conclusions In this study, undiluted amiodaronecan effectively reduced the defibrillation times and energy. Although diluted amiodaronecan release the side effect of hypotension which was transient, it didn't significantly improved cardiac electric activity and delayed to start CPR.