Application of chaotic vibrations to the development of a bedsore-prevention bed

混沌振动在防褥疮床研制中的应用

基本信息

批准号：
15560194
负责人：
NAGAI Ken-ichi
金额：
$ 1.6万
依托单位：
Gunma University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560194/
关键词：
Chaos Biomedical Measurements Nonlinear Time-Series Analysis Nursing Sound and Vibration Flexible Structures

项目摘要

Recently, the number of bedridden old people is increasing. One of the most serious problems of these people is a bedsore, also called pressure ulcers, which is caused by inadequate blood supply due to prolonged pressure by bony areas resulting in necrosis of tissues. To prevent the bedsores, it is necessary to relax the pressure on one's body, which requires large manpower for nursing. Application of mechanical vibrations, especially chaotic vibrations with broadband spectra, is a potential way to prevent the bedsores. In this research, biological signals of a human body subjected to time-varying pressure are measured and analyzed as a fundamental study aiming at developing a bedsore-prevention bed. Sinusoidal pressure and chaotic pressure are applied to the loins, in reclined position on the bed. Electrical signals on the skin are then measured : an electrocardiogram (ECG) is detected from the chest of the body, while an electromyogram (EMG) is detected from the muscles of both arms. Pulse sound diagram (PSD) is recorded with a microphone. Based on time-series of ECG, EMG and PSD, the signals were then analyzed by power spectra and by calculation of their Maximum Lyapunov exponents. It is found that waveforms of EMG of a human body are sensitive to sinusoidal pressure, while waveforms of ECG are not. The maximum Lyapunov exponents of EMG after the excitation whether by sinusoidal or chaotic pressure take larger values than those before the excitation, which suggests that signals from the muscles are activated by the time-varying pressures. In contrast, chaotic pressure gives the ECG lower Maximum Lyapunov exponent in both normal and blood-stagnated condition. Same trend is found for the PSD under blood-stagnated condition. These results suggest that time series of heartbeat tends to become periodically by the chaotic pressure.

最近，卧床不起的老人数量正在增加。这些人中最严重的问题之一是床索，也称为压溃疡，这是由于骨质区域长时间压力导致血液供应不足而导致组织坏死引起的。为了防止卧床，有必要放松身上的压力，这需要大量的哺乳。机械振动的应用，尤其是与宽带光谱的混乱振动，是预防床架的潜在方法。在这项研究中，测量并分析了受时变压力的人体的生物学信号，作为一项旨在开发卧床预防床的基本研究。正弦压力和混沌压力施加到腰部的腰部，在床上的位置。然后测量皮肤上的电信号：从人体的胸部检测到心电图（ECG），而从两个臂的肌肉中检测到肌电图（EMG）。用麦克风记录脉冲声音图（PSD）。然后根据EPG，EMG和PSD的时间序列，通过功率谱和计算其最大Lyapunov指数来分析信号。发现人体EMG的波形对正弦压力敏感，而ECG的波形却不是敏感的。激发后EMG的最大Lyapunov指数无论是正弦压力还是混沌压力都比激发前的值大，这表明来自肌肉的信号被随时间变化的压力激活。相比之下，混沌压力在正常和血液stagnation条件下都使ECG较低的最大Lyapunov指数。在血液吞噬状态下，PSD也发现了同样的趋势。这些结果表明，随着混乱的压力，心跳的时间序列倾向于定期变成。