Background The choice of a defibrillation or a cardiopulmonary resuscitation （CPR）-first strategy in the treatment of prolonged cardiac arrest （CA） is still controversial. The purpose of this study was to compare ...Background The choice of a defibrillation or a cardiopulmonary resuscitation （CPR）-first strategy in the treatment of prolonged cardiac arrest （CA） is still controversial. The purpose of this study was to compare the effects of defibrillation or CPR administered first on neurological prognostic markers in a porcine model of prolonged CA. Methods After 8 minutes of untreated ventricular fibrillation （VF）, 24 inbred Chinese Wuzhishan minipigs were randomized to receive either defibrillation first （ID group, n=12） or chest compression first （IC group, n=12）. In the ID group, a shock was delivered immediately. If defibrillation failed to attain restoration of spontaneous circulation （ROSC）, manual chest compressions were rapidly initiated at a rate of 100 compressions/min and a compression-to-ventilation ratio of 30：2. If VF persisted after five cycles of CPR, a second defibrillation attempt was made. In the IC group, chest compressions were delivered first, followed by a shock. After successful ROSC, hemodynamic status and blood samples were obtained at 0.5, 1, 2, 4, 6, and 24 hours after ROSC. Porcine-specific neuron-specific enolase （NSE） and S100B were measured from sera using enzyme-linked immunosorbent assays. Porcine cerebral performance category scores were used to evaluate preliminary neurological function following 24 hours recovery. Surviving pigs were sacrificed at 24 hours after ROSC and brains were removed for electron microscopy analysis. Results The number of shocks, total defibrillation energy, and time to ROSC were significantly lower in the ID group compared with the IC group. Compared with the IC group, S100B expression was decreased at 2 and 4 hours after ROSC, and NSE expression decreased at 6 and 24 hours after ROSC in the ID group. Brain tissue analysis showed that injury was attenuated in the ID group compared with the IC group. There were no significant differences between 6 and 24 hours survival rates. Conclusion Defibrillation first may result in a shorter tim展开更多
在对传统LTE-OFDM深入研究的基础上,针对滤波OFDM(F-OFDM)技术特点,设计了数据帧格式,建立F-OFDM基带系统模型,通过对2个子带进行滤波处理,实现了各个子带波形的解耦,并仿真验证其性能。仿真结果表明:在AWGN信道下,F-OFDM系统的下行基...在对传统LTE-OFDM深入研究的基础上,针对滤波OFDM(F-OFDM)技术特点,设计了数据帧格式,建立F-OFDM基带系统模型,通过对2个子带进行滤波处理,实现了各个子带波形的解耦,并仿真验证其性能。仿真结果表明:在AWGN信道下,F-OFDM系统的下行基带信号的带外衰减超过60 d B,较LTE-OFDM高28 d B,F-OFDM与LTE-OFDM的BER接近一致,与理论值的差异小于1 d B。相比LTE-OFDM系统,F-OFDM系统在保证误码率性能的前提下,大大改善了带外频谱泄漏,并进一步提高了频谱效率。展开更多
基金This research was supported by a grant from the Beijing Natural Science Foundation （No. 7132092）.
文摘Background The choice of a defibrillation or a cardiopulmonary resuscitation （CPR）-first strategy in the treatment of prolonged cardiac arrest （CA） is still controversial. The purpose of this study was to compare the effects of defibrillation or CPR administered first on neurological prognostic markers in a porcine model of prolonged CA. Methods After 8 minutes of untreated ventricular fibrillation （VF）, 24 inbred Chinese Wuzhishan minipigs were randomized to receive either defibrillation first （ID group, n=12） or chest compression first （IC group, n=12）. In the ID group, a shock was delivered immediately. If defibrillation failed to attain restoration of spontaneous circulation （ROSC）, manual chest compressions were rapidly initiated at a rate of 100 compressions/min and a compression-to-ventilation ratio of 30：2. If VF persisted after five cycles of CPR, a second defibrillation attempt was made. In the IC group, chest compressions were delivered first, followed by a shock. After successful ROSC, hemodynamic status and blood samples were obtained at 0.5, 1, 2, 4, 6, and 24 hours after ROSC. Porcine-specific neuron-specific enolase （NSE） and S100B were measured from sera using enzyme-linked immunosorbent assays. Porcine cerebral performance category scores were used to evaluate preliminary neurological function following 24 hours recovery. Surviving pigs were sacrificed at 24 hours after ROSC and brains were removed for electron microscopy analysis. Results The number of shocks, total defibrillation energy, and time to ROSC were significantly lower in the ID group compared with the IC group. Compared with the IC group, S100B expression was decreased at 2 and 4 hours after ROSC, and NSE expression decreased at 6 and 24 hours after ROSC in the ID group. Brain tissue analysis showed that injury was attenuated in the ID group compared with the IC group. There were no significant differences between 6 and 24 hours survival rates. Conclusion Defibrillation first may result in a shorter tim
文摘在对传统LTE-OFDM深入研究的基础上,针对滤波OFDM(F-OFDM)技术特点,设计了数据帧格式,建立F-OFDM基带系统模型,通过对2个子带进行滤波处理,实现了各个子带波形的解耦,并仿真验证其性能。仿真结果表明:在AWGN信道下,F-OFDM系统的下行基带信号的带外衰减超过60 d B,较LTE-OFDM高28 d B,F-OFDM与LTE-OFDM的BER接近一致,与理论值的差异小于1 d B。相比LTE-OFDM系统,F-OFDM系统在保证误码率性能的前提下,大大改善了带外频谱泄漏,并进一步提高了频谱效率。
