Faculty of System Design, Tokyo Metropolitan University, 6-6, Asahigaoka, Hino, Tokyo 191-0065, Japan.
J Clin Monit Comput. 2013 Jun;27(3):351-6. doi: 10.1007/s10877-013-9448-3. Epub 2013 Mar 6.
We developed a practicable, non-contact, autonomic activation monitoring system using microwave radars without imposing any stress on monitored individuals. Recently, the rapid increase in the aging population has raised concerns in developed countries. Thus, hospitals and care facilities will need to perform long-term health monitoring of elderly patients. The system allows monitoring of geriatric autonomic dysfunctions caused by chronic diseases, such as diabetes or myocardial infarction (MI), while measuring vital signs in non-contact way. The system measures heart rate variability (HRV) of elderly people in bed using dual, 24-GHz, compact microwave radars attached beneath the bed mattress. HRV parameters (LF, HF, and LF/HF) were determined from the cardiac peak-to-peak intervals, which were detected by radars using the maximum entropy method. We tested the system on 15 elderly people with and without diabetes or MI (72-99 years old) from 7:00 p.m. to 6:00 a.m. at a special nursing home in Tokyo. LF/HF obtained by the system correlated significantly (R = 0.89; p < 0.01) with those obtained by Holter electrocardiography (ECG). Diabetic subjects showed significantly lower LF (radar) than non-diabetic (119.8 ± 57.8 for diabetic, 405.9 ± 112.6 for non-diabetic, p < 0.01). HF (radar) of post-MI subjects was significantly lower than that of non-MI (219.7 ± 131.7 for post-MI and 580.0 ± 654.6 for non-MI, p < 0.05). Previous studies using conventional ECG reveal that diabetic neuropathy decreases LF, and also MI causes parasympathetic attenuation which leads to HF reduction. Our study showed that average SDNN of post-MI patients is smaller than 50 ms which is known to have high mortality. The non-contact autonomic activation monitoring system allows a long-term health management especially during sleeping hours for elderly people at healthcare facilities.
我们开发了一种实用的、非接触式的自主激活监测系统，该系统使用微波雷达，不会给被监测者带来任何压力。最近，人口老龄化的快速增长引起了发达国家的关注。因此，医院和护理机构将需要对老年患者进行长期健康监测。该系统允许监测由慢性病引起的老年自主功能障碍，如糖尿病或心肌梗死（MI），同时以非接触的方式测量生命体征。该系统使用安装在床垫下的两个 24GHz 紧凑型微波雷达，测量卧床老年人的心率变异性（HRV）。使用雷达通过最大熵法检测到的心脏峰峰值间隔来确定 HRV 参数（LF、HF 和 LF/HF）。我们在东京一家特殊养老院对 15 名患有和不患有糖尿病或 MI 的老年人（72-99 岁）进行了测试，时间为晚上 7 点至早上 6 点。系统获得的 LF/HF 与动态心电图（ECG）获得的 LF/HF 显著相关（R = 0.89；p <0.01）。与非糖尿病患者相比，糖尿病患者的 LF（雷达）明显更低（糖尿病患者为 119.8 ± 57.8，非糖尿病患者为 405.9 ± 112.6，p <0.01）。MI 后患者的 HF（雷达）明显低于非 MI 患者（MI 后为 219.7 ± 131.7，非 MI 后为 580.0 ± 654.6，p <0.05）。使用传统 ECG 的先前研究表明，糖尿病性神经病会降低 LF，并且 MI 会导致副交感神经衰减，从而导致 HF 降低。我们的研究表明，MI 后患者的平均 SDNN 小于 50ms，这与高死亡率有关。非接触式自主激活监测系统允许在医疗保健设施中对老年人进行长期健康管理，特别是在睡眠期间。
