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Development of Noninvasive Artificial Baroreflex System for Severe Orthostatic Hypotension

开发治疗严重直立性低血压的无创人工压力感受反射系统

基本信息

批准号：
18300172
负责人：
YAMASAKI Fumiyasu
金额：
$ 10.61万
依托单位：
Kochi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18300172/
关键词：
Advanced device Biomedical Engineering Orthostatic Hypotension Baroreflex Noninvasive Therapeutic System

项目摘要

Baroreflex failure due to progressive neurodegenerative diseases in middle age and elderly induced severe orthostatic hypotension and syncope. However, commonly used intervention can not restore the function and most affected patients remain bedridden. Therefore, we developed noninvasive artificial baroreflex system with clinical investigation for two years.1. Estimation of baroreflex open-loop function : The open-loop transfer function of Hnative(f) estimated by comparing autonomic failure patients to normal subjects showed low-pass characteristics with a cut off frequency of 0.01Hz. The steady-state gain at the lowest frequency was 5.3.2. Estimation of transfer function of HSTM-SAP(f) from abdominal pants pressure to arterial pressure (AP) : Averaged step response function in patients with autonomic failure showed rapid AP response to 90% of steady state by abrupt increase of pants pressure. The steady-state gain at the lowest frequency was 0.7±0.3 mmHg/mmHg.3. Design of artificial vasomotor center : The instantaneous AP response to pants pressure was numerically simulated with the averaged HSTM-SAP(f). Based on these results, proportional correction factor of Kp was set at 0.4, and integral correction factor of Ki was set at 0.2, so that the system could quickly and effectively attenuate the effect of the AP decline. The system was leaded the artificial vasomotor center with these correction factors.4. Setting up of the system and clinical application : The devise was composed of PC with the vasomotor center, AP monitor, solenoid control valve, compressed air cylinder and abdominal air pants. A sudden tilting produced a rapid progressive fall in AP of approximately 20 mmHg, when the system was activated, the AP fall was attenuate the drop in AP of 11mmHg.5. Possibility of AP control with a thigh and lower leg cuff A step response function showed rapid AP response to the steady state by abrupt increase of cuff pressure in 20 seconds.

中老年人进行性神经退行性疾病引起的压力感受反射衰竭可引起严重的直立性低血压和晕厥。然而，常用的干预措施无法恢复功能，大多数受影响的患者仍卧床不起。为此，我们经过两年的临床研究，开发出无创人工压力反射系统。 1．压力反射开环功能的估计：通过比较自主神经衰竭患者与正常受试者估计的Hnative(f)的开环传递函数显示出截止频率为0.01Hz的低通特性。最低频率下的稳态增益为5.3.2。 HSTM-SAP(f)从腹部裤压到动脉压(AP)的传递函数的估计：自主神经衰竭患者的平均阶跃响应函数显示，通过裤压的突然增加，AP快速响应至稳态的90%。最低频率下的稳态增益为0.7±0.3 mmHg/mmHg.3。人工血管舒缩中心的设计：用平均 HSTM-SAP(f) 对裤子压力的瞬时 AP 反应进行数值模拟。根据这些结果，将Kp的比例校正因子设置为0.4，将Ki的积分校正因子设置为0.2，以便系统能够快速有效地衰减AP下降的影响。系统以这些校正因子引导人工血管舒缩中枢。 4．系统搭建及临床应用：该装置由带有血管舒缩中枢的PC机、AP监测仪、电磁控制阀、压缩气缸和腹部气裤组成。突然倾斜会导致 AP 快速逐渐下降约 20 mmHg，当系统启动时，AP 下降会减弱 AP 下降 11mmHg.5。通过大腿和小腿袖带进行 AP 控制的可能性阶跃响应功能显示，通过在 20 秒内突然增加袖带压力，AP 可以快速响应到稳定状态。