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Development of magnetic defibrillator

磁力除颤器的研制

基本信息

批准号：
05558110
负责人：
YAMAGUCHI Masuhiro
金额：
$ 6.72万
依托单位：
Fac.Eng.Yokohama Nat'l Univ.
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至无数据
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05558110/
关键词：
Biomagnetic stimulation Myelinated nerve Pulsed magnetic field Sciatic nerve Defibrillation

项目摘要

We developed"magnetic defibrillation"(MDF)by which ventricular fibrillation was converted to sinus rhythm in emergency. MDF can be realized if the magnetic field is strong and long enough to produce eddy currents for defibrillation. In this study key technology for MDF was developed as follows.(1)Effective stimulating coils were developed for magnetic excitation of cardiac muscle, and eddy currents produced by the coils were observed andcalculated. The coils were flat solenoids made from Be-Cu alloy, having a structure at satisfactory mechanical strength. Two coils were effectively combined to intensify stimulus fields in a target heart. The spatial distribution of the eddy current density was measured for a cylindrical volume filledwith saline solution. The result agreed well with the eddy current density calculated by the finite difference method. As a consequence, the present coil systemwas recognized for effective for MDF.(2)Magnetic nerve stimulation was experimentally and analyti … More cally studied in relation to the waveform effect in magnetic stimulation. In the experiment frog sciatic narves were stimulated by magnetic fields with damped sinusoidal oscillations. The threshold of nervous excitation depends on the cycle of the oscillation, and the one-cycle period of the stimulus is effective in exciting the nerve. In the analysis the myelinated nerve was stimulated by timevarying magnetic fields. The analysis on the waveform dependence agreed well with the experimental result.As a result, we determined effective waveforms in magnetic stimulation.(3)Magnetic heart stimulation was analytically studied on the excitation threshold for a variety of magnetic stimulus waveforms. A cell membrane of the ventricular muscle modeled by Beeler-Reuter was used. The threshold for the damped sinusoidal pulses depended on the number of cycles of the oscillation, resulting in the lowest threshold for one-quarter pulse. Applying double crowbar pulses considerably lowers the excitation threshold. Less

我们开发了“磁除颤”（MDF），可以在紧急情况下将室颤转化为窦性心律。如果磁场足够强且足够长以产生用于除颤的涡电流，则可以实现除颤。在这项研究中，开发的关键技术，为可持续发展如下。（1）研制了磁激励心肌的有效激励线圈，并对其产生的涡流进行了观测和计算。线圈是由Be-Cu合金制成的扁平线圈，具有令人满意的机械强度的结构。两个线圈被有效地组合以增强目标心脏中的刺激场。本文测量了充有生理盐水的圆柱体中涡流密度的空间分布。计算结果与有限差分法计算的涡流密度吻合较好。因此，目前的线圈系统被认为是有效的。（2）磁刺激神经的实验研究和分析表明，磁刺激神经的功能与磁刺激神经的功能密切相关。 ...更多信息研究了磁刺激中的波形效应。在实验中，用阻尼正弦振荡磁场刺激蛙坐骨神经。神经兴奋的阈值取决于振荡的周期，并且刺激的一个周期周期在兴奋神经方面是有效的。在分析中，有髓神经被时变磁场刺激。波形依赖性分析与实验结果吻合较好，从而确定了磁刺激的有效波形。（3）分析了不同磁刺激波形对心脏磁刺激的激发阈值的影响。使用了由Beeler-Printer建模的心室肌的细胞膜。阻尼正弦脉冲的阈值取决于振荡的周期数，导致四分之一脉冲的阈值最低。应用双撬棍脉冲大大降低了激励阈值。少