心脏除颤器测试分析仪

除颤器是心脏急救系统的重要仪器；为保证其性能，必须定期检定。设计了一种智能式除颤器分析仪，它不仅能准确计量除颤器放电能量，而且可以输出各种心电波形。     

可穿戴式心律转复除颤器研究现状和发展趋势

部分心源性猝死高风险患者存在植入式心脏复律除颤器禁忌证。近年来,可穿戴式心律转复除颤器(Wearable Cardioverter Defibrillator, WCD)凭借穿戴方便、可重复使用、除颤效果可靠等优点,临床应用逐渐增多。本文阐述了WCD的技术原理及优势,总结了在预防心源性猝死以及其他潜在临床症状研究中应用进展,并分析了该设备的国内外市场现状及未来的研发趋势。     

除颤分析仪释放能量示值误差校准方法的研究

心脏除颤器的急救效果与其释放能量的强度有关,除颤器输出能量的准确与否直接影响患者的生命安全。除颤分析仪是分析评判除颤器性能的关键设备,虽然《JJF 1860-2020除颤分析仪校准规范》将于今年3月实施,但整体校准过程仍有细节需要探讨。本文介绍了一种基于电压电流比较测量法原理设计的除颤分析仪释放能量示值误差校准方法,其极大的降低了除颤分析仪释放能量示值误差校准时操作的复杂性和危险性,满足规范中的技术要求。课题组已经完成了样机的制作,鉴于其集成度高,操作简便、安全,适合于在省/市级计量校准部门使用。     

用于低能量除颤的除颤器设计

设计了用于低能量除颤的,可灵活调节放电脉冲宽度和准确测量实际放电能量的除颤器.该除颤器的放电波形为双相指数截尾波,通过人工设置,可释放1～3组双相指数截尾波;放电脉冲的宽度、各脉冲之间的时间间隔可人工灵活调节,最小步长为0.1 ms;可测量放电前后储能电容电压,再根据储能电容的容值准确地计算出实际放电能量.该除颤器在双相指数截尾波的基础上,通过调节放电脉冲的宽度、各脉冲之间的时间问隔及脉冲数量,优化放电波形,达到低能量除颤的目的.已在20余例低能量除颤的动物实验中应用,各项功能符合设计要求.     

基于ARM和Linux的AED控制系统设计

本文提出一种基于ARM9内核的嵌入式处理器S3C2440的自动体外除颤器控制系统的设计方案,详细介绍人体电阻抗测量系统设计和心率测量系统设计,以及基于嵌入式Linux操作系统的除颤控制软件设计,并描述软件的功能划分和控制策略的实现。该自动体外除颤控制系统具备心脏节律分析系统和电击咨询系统功能。     

医疗设备配置ups不间断电源系统故障解决及维护方案

通过分析医院医疗设备配置的不间断电源系统故障及风险点,探讨ups系统故障解决方案及预防性维护方法,更好地应对电源系统的突发故障,降低故障率,保障系统处在最佳工作状态,确保医疗设备特别是呼吸机、除颤器、麻醉机等急救类设备以及重点科室手术室、重症医学科、急诊科等科室医疗设备的正常安全使用,确保临床诊疗顺利进行。     

基于嵌入式系统的体外除颤器

电击除颤是最有效的治疗室颤(VF)的方法.本文介绍了一种基于嵌入式系统的体外除颤器.该设计选用了两款合适的嵌入式处理器,在保证系统的性能和低功耗要求的同时,方便了系统的实现.整个设计分为监护控制单元、心电采集单元和除颤单元三个部分.试验结果表明,使用该设备可以成功终止室颤.     

外科手术中心外/心内通用复律除颤器的研制

为应对心外科手术中经常发生的房颤、室速和室颤等心律失常,需研制具有精确能量计量和阻抗补偿功能、心外/心内通用的低能量复律除颤器.系统分4部分进行设计:复律除颤模块、R波识别模块、阻抗检测模块和供电模块;高压、低压电路之间全部进行隔离.实验结果表明,该系统可快速充电、准确释放低能量双向指数截尾波;R波准确识别率高;可进行阻抗分级补偿;释放能量计量值较精确.证明其具备在外科手术中实施心外/心内电击复律除颤的能力.     

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山东临工 L953F型轮式装载机

正该机掘起力大,转弯半径小,作业范围广,适用性强。其符合国三排放标准的电控发动机,动力强劲,可靠性高。具备故障检测接口,方便发动机的检测与维护。配置临工行星式变速器,操作简便。配置临工加强型驱动桥,可靠性高。采用加强型前、后车架,载荷分布合理,承载能力强,稳定性好。采用钢结构驾驶室,视野开阔,驾驶室内进行优化布置,操作空间更大。采用临工自主研发     

The prediction of the impedance of the thorax to defibrillating current.

In this paper a technique for predicting thoracic impedance to defibrillator pulses is described. The impedance to low-current (1.0 mA) high-frequency (10-500kHz) sinusoidal current is used as an indicator of the impedance of the thorax to high-current, damped sinusoidal waveform pulses. Results from 71 dogs to which defibrillator shocks of 4 to 220 A peak current were applied show that thoracic impedance can be predicted by this method. This information indicates that it is possible to design a defibrillator that can automatically measure chest impedance prior to a defibrillation shock and deliver a predetermined peak current to the subject.     

Considerations in the development of the automatic implantable defibrillator.

A highly reliable ventricular fibrillation detector and a satisfactory electrode system for delivering defibrillating pulses to the heart play a central role in the development of an automatic implantable defibrillator suitable for clinical use. Among the four implanted electrode designs tested, the combination of an electrode placed in the superior vena cava with a conformal electrode on the apex of the heart provided satisfactory defibrillation thresholds with ease of implantation. A new sensing method is also described for which an electrogram derived from the defibrillating electrodes is used as input. A form of a density function is developed for a filtered version of the input, ventricular fibrillation being characterized by a density curve lacking a large peak occurring at a level corresponding to the baseline of the filtered signal. These ideas are being incorporated into the design of a prototype implantable defibrillator delivering pulses of 24 joules.     

Electode catheter for transvenous defibrillation.

Development of an implantable automatic defibrillator is dependent on achieving a reduction in the energy required for defibrillation, which is related to an optimal electrode configuration. This study investigated the use of a transvenous catheter electrode utilizing the damped sinusoidal waveform; compared the defibrillation effectiveness of varying the configuration of the four electrode units and of using a catheter/subcutaneous metal plate combination; and determined the lowest energy level necessary for near consistent transvenous defibrillation.     

User views on standards for defibrillators

User views on the need for defibrillator standards were surveyed as part of a multifaceted study of defibrillator use in Canadian hospitals. The majority of users favor standardization of performance, labeling, and use characteristics. They also prefer that all defibrillators incorporate cardioversion capability. Most users prefer that the defibrillator automatically switch to the emergency mode after delivery of a cardioversion shock, but almost one half of the physicians preferred the unit to remain in the synchronized mode as set. Most users are in favor of all equipment operating in the same fashion, but paramedics are not. Only a minority believes that cardioversion features are a cause of confusion, yet conversations with biomedical engineers indicate that this confusion is a common problem among the users. Virtually all users prefer that necessary standards for safety and efficacy should be mandatory for both manufacturers and hospitals.     

Some research needs in defibrillation and CPR

The Fourth Purdue Conference on Cardiac Defibrillation and Cardiopulmonary Resuscitation identified needed defibrillation research, including an appropriate animal model, threshold validity, effects of polarity, and an easy-to-operate defibrillator. CPR research needs include better protocols, hemodynamics and survival studies, the role of pulmonary edema, re-examination of sudden death, and transchest pacing.     

Transthoracic impedance to direct current discharge: effect of repeated countershocks.

The effect of repeated countershocks on transthoracic apparent impedance to direct current (dc) defibrillator discharges was studied. Repeated dc countershocks result in a progressive decrease in transthoracic apparent impedance that is dependent upon the time interval between countershocks. This decrease was significantly greater in the group of animals shocked at 3-min intervals compared to the groups shocked at 15-sec intervals (P less than 0.001) or at 1-min intervals (P less than 0.005). Since lowered impedance results in higher delivered current for the same energy setting on a defibrillator, this observation may help to explain the enhanced effectiveness of repeated countershocks in defibrillation. Plots of simultaneous current against voltage during transthoracic dc discharge revealed that the current lagged slightly behind voltage during the rising phase of the recording, but that current and voltage were nearly simultaneous during the falling phase. This effect appears to be similar to an ionization phenomenon in that the effective impedance asymptotically approaches a lower value with increasingly applied voltage. This might explain why transthoracic impedance is highest at low energy countershocks and decreases with higher energy countershock.     

Design of an ultrahigh-energy hydrogen thyratron/SCR research defibrillator.

The design features of an ultrahigh-energy research defibrillator are described. Three voltage sources are used. The first is a 60-Hz supply of adjustable amplitude and duration for inducing fibrillation. The second source uses an 18.000-joule capacitor bank which can be charged to 800, 1600, or 2400 volts. SCRs in series with the chest are used to initiate the discharge, and SCRs shunting the capacitor bank terminate the discharge. The third source employs another 18,000-joule capacitor bank which can be charged to 5000, 10,000 or 15,000 volts. In this source, large ceramic-enveloped hydrogen thyratrons are used for both initiating and terminating the discharge. In the second and third sources, which can deliver rectangular, trapezoidal, truncated exponential, or untruncated exponential waveforms, capacitor charge time is 10 sec and the duration of the delivered shock is continuously adjustable from 100 musec through 1 sec.