基于脉搏波速法的无创连续血压检测系统

目的设计基于脉搏波速法的无创连续血压测量系统。方法分析基于脉搏波传导时间计算动脉血压的原理，提出脉搏波传导时间与血压的关系方程，并论述了方程参数标定方法。根据心电与脉搏波信号的特点，采用数字信号处理器和16位A／D等先进的电子器件设计了同步采集心电和脉搏波信号，准确计算脉搏波传导时间并计算动脉血压的仪器。结果实验表明，仪器的测量误差优于AAMI推荐标准。结论本系统能满足无创连续血压测量的基本要求，已应用于航天员日常训练。     

基于容积脉搏波的无创连续血压测量系统

目的 设计一种基于容积脉搏波的无袖套连续血压测量系统.方法 从单一容积脉搏波中提取脉搏波传导时间,经逐步回归分析与血压建立血压估算方程,实现无创连续血压测量.结果 通过对不同人群血压检测,并与鱼跃牌水银血压计进行对比,结果表明该方法和传统方法具有较好的测试一致性,测量误差优于美国医疗仪器促进协会(AAMI)推荐标准.结论 该方法同传统血压测量方法相比,测量方便,可彻底摆脱缚带,并能实现无创连续测量,具有更广阔的应用前景.     

一种无创检测桡动脉脉搏波速度的新方法

目的:提出一种同步采集肱动脉脉搏波信号和指尖脉搏波信号无创检测桡动脉脉搏波速度的新方法.方法:用二次函数对起跳点波段按最小二乘法原理逼近计算出脉搏波先后传播到肱动脉和指尖这段距离的时间.结果:大量的病例分析和临床测试表明:脉搏波传导速度与年龄的正相关性为r=0.46,与脉压的正相关性为r=0.622.该算法能够解决波谷...     

基于 PPG的血管动力学参数检测研究

目的利用指尖PPG信号,获取血流、血管及微循环等心血管动力学参数。方法提出由反射式传感器DCM03及血氧模拟前端AFE4490设计指尖脉搏采集系统,并对原始脉搏波信号进行滤波,最终采用去噪效果较好的4阶ChebyⅡ滤波器降噪。对降噪后的信号进行二次微分得到加速脉搏波,对两种不同的加速脉搏波分别计算脉搏波传导时间,最终建立脉搏波传导时间和血压的估算模型,并由此估算心搏输出量、心搏指数等其他心血管动力学参数。结果对30个测试对象进行系统测试实验,得到收缩压和舒张压标准值与测试值之间的相关系数分别为0.9845和0.9663,而心率、心脏指数及心搏指数的相关系数为0.9779、0.8463及0.8133。结论系统测试值与标准值之间相关性较好,可为心血管疾病预测的研究提供一定参考依据。     

实验鼠无创生理信号监测系统设计

目的 研制一种实验鼠无创可穿戴生理信号监测系统,实现在生物医学和药学研究中,连续无创地监测实验鼠的生理信号.方法 系统由可穿戴终端、生理信号接收主机和监控软件组成.可穿戴终端采用无线微控制器CC2640R2F实现实验鼠心电图(ECG)、体温(BT)和运动量(AL)的采集与无线传输;生理信号接收主机通过低功耗蓝牙技术,接...     

冠心病病人脉搏变异性信号的去趋势波动分析

目的 本文运用非线性方法分析冠心病人与健康人的脉搏变异性信号,研究两者之间不同的特征,以便无创地检测冠心病及监测冠心病人的病情. 方法 利用PPG传感器采集健康人(18人)和冠心病患者(18人)的指尖脉搏波信号,并从脉搏波中提取脉搏变异性信号,利用去趋势波动分析算法对其进行分析,计算两类病人各自的标度指数.结果 经过去趋势波动算法的分析,发现冠心病病人的平均标度指数: 短程α1、长程α2 和全程α明显低于健康人.结论 运用去趋势波动算法分析健康人和冠心病患者的脉搏变异性信号,发现冠心病病人的平均标度指数α1、α2 和α明显有别于健康人,这些现象的发现有助于对冠心病及冠心病人的病情进行无创检测和监测.     

基于多波长无创血红蛋白检测系统研究

目的研究开发一种便携式无创血红蛋白检测系统,实现人体总血红蛋白浓度的连续、实时监测。方法系统采用8个波长发光二极管(LED)作为光电容积脉搏波描记法(PPG)信号光源,联合约束独立成分分析和自适应滤波新方法消除PPG源信号的运动伪迹,应用主成分分析(PCA)和后向反馈人工神经网络(BP-ANN)相结合的新方法对PPG信号特征进行提取并利用十折交叉验证方法建立血红蛋白浓度的预测模型,无创系统样机和传统有创血液分析仪同步检测106例志愿者血红蛋白浓度。结果无创检测结果(SpHb_BP)和传统有创检测结果(Lab_tHb)的均方根误差为1.02g/dL,相关系数为0.73(P0.001);Bland-Altman图显示SpHb_BP与Lab_tHb平均偏倚绝对值为0.05g/dL,99.1%(105/106)的点在95%一致性界限内。结论基于8波长PPG信号实现了无创血红蛋白检测系统研制,系统与临床有创血红蛋白浓度检测结果具有较好的一致性。     

多方法检测肱-踝动脉脉搏波传导速度的比较研究

目的:比较分析同一组受试者运用多种方法检测获得的肱-踝动脉段脉搏波传导速度(brachial ankle pulse wave velocity,baPWV),探讨将超声技术引入脉搏波传导速度检测的可行性及准确性。方法:纳入30例正常人,分别行日本Colin动脉硬化仪检测、联合多普勒超声及脉搏波传感器同步检测、仅多普勒超声检测baPWV,并将结果进行比较分析。结果:动脉硬化仪检测得到的baPWV为(1 118.20±176.42)cm/s;将脉搏波传感器放置于肱动脉、多普勒探头放置于胫后动脉同步检测的baPWV为(1 135.74±246.26)cm/s;仅用多普勒超声分2次分别将探头放置于肱动脉及胫后动脉时测得的baPWV为(1 048.96±117.24)cm/s。多普勒超声及脉搏波传感器联合应用与动脉硬化仪检测得到的baPWV呈显著正相关(r=0.549,P0.01)。多普勒超声与动脉硬化仪检测得到的baPWV无相关性(r=0.277,P0.05)。结论:联合运用超声多普勒与脉搏波传感器为PWV的检测提供了新途径,测量数据准确度较高;仅运用多普勒超声分2次检测PWV的方法误差较大。     

123例飞行员臂踝脉搏波传导速度测定及相关因素分析（摘要）

目的探讨飞行员臂踝脉搏波传导速度的情况及其相关影响因素。方法随机选择123名飞行员,按年龄分为30岁以下、30-39岁以及40岁以上3组,应用动脉硬化测定仪测定臂踝脉搏波传导速度,同时确定飞行员身高、体重、体重指数、收缩压、舒张压、脉压、飞行时间、是否吸烟等。对比各年龄段吸烟组与非吸烟组飞行员臂踝脉搏波传导速度,分别计算臂踝脉搏波传导速度与年龄、飞行时间、体重指数、收缩压、舒张压、脉压的直线相关系数。     

检测头部血压和动态过程的头高位倾斜实验系统设计

目的 设计一个可以检测头部血压和动态过程的头高位倾斜实验(head-up tilt, HUT)系统,以提高HUT实验的效能.方法 通过对阻抗血流图的B点和颞浅动脉脉搏波起点为标志点得到的脉搏波传导时间(pulse wave transit time,PWTT)进行个体化校正,获得头部血压.基于改进的倾斜床,设计了可监测连续动态血压、心电图、心音、呼吸和阻抗血流图等人体生理信号的实验系统;并通过3名志愿者的HUT实验检验系统的可靠性.结果 基于精确的PWTT的个体化校正可以实现头部血压测量.在HUT过程中系统可连续、稳定地记录各项生理指标;可特征地显示出头部血压的最低值和血压的动态调节过程及整体水平.结论 本系统可准确地反映HUT中头部血压的连续、动态变化过程,从而为评价人体的心血管调节功能提供更丰富的信息,为研究高性能飞机飞行员对加速度应激的即刻反应提供了可能.     

Electrocardiogram acquisition during MR examinations for patient monitoring and sequence triggering

We have developed a method for measuring the electrocardiogram (ECG) continuously during MR examinations. In contrast to ECG acquisition by wires, our new method is to amplify and convert the ECG into an optical signal directly above the patient's heart. The optical signal is transmitted out of the magnet bore by optical fiber. The small and fixed dimensions of the ECG amplifier avoid interactions with the MR system because of shorter electrical structures and smaller enclosed areas. Tests of the proposed device in a 1.5 Tesla MR system show that continuous and reliable ECG monitoring and sequence triggering are possible.     

基于Android平台的心率变异性检测系统

目的研制一种适合于家庭监护、远程医疗、操作简便的便携式心率变异性(heart rate variability,HRV)检测仪。方法利用Android平台为数据处理中心和显示器,以STM32为微控制器,设计了一种通过反射式光电容积脉搏波(PPG)描记法采集腕部脉搏波信号的HRV检测系统。采集器采集的信号经模数转换后,由蓝牙发送至Android客户端并实时显示脉搏波,完成测量后对脉搏波数据进行滑动平均滤波处理,短时平均幅度差函数(AMDF)进行周期检测等,最终得出HRV信息,且数据可云存储。结果18个测试对象进行系统测试实验,得出系统平均相对误差为3.8%。结论所研制的检测系统操作简便,运行稳定可靠,可满足家庭监护使用。     

Adaptive noise cancellation to suppress electrocardiography artifacts during real-time interventional MRI

Purpose:

To develop a system for artifact suppression in electrocardiogram (ECG) recordings obtained during interventional real‐time magnetic resonance imaging (MRI).

Materials and Methods:

We characterized ECG artifacts due to radiofrequency pulses and gradient switching during MRI in terms of frequency content. A combination of analog filters and digital least mean squares adaptive filters were used to filter the ECG during in vivo experiments and the results were compared with those obtained with simple low‐pass filtering. The system performance was evaluated in terms of artifact suppression and ability to identify arrhythmias during real‐time MRI.

Results:

Analog filters were able to suppress artifacts from high‐frequency radiofrequency pulses and gradient switching. The remaining pulse artifacts caused by intermittent preparation sequences or spoiler gradients required adaptive filtering because their bandwidth overlapped with that of the ECG. Using analog and adaptive filtering, a mean improvement of 38 dB (n = 11, peak QRS signal to pulse artifact noise) was achieved. This filtering system was successful in removing pulse artifacts that obscured arrhythmias such as premature ventricular complexes and complete atrioventricular block.

Conclusion:

We have developed an online ECG monitoring system employing digital adaptive filters that enables the identification of cardiac arrhythmias during real‐time MRI‐guided interventions. J. Magn. Reson. Imaging 2011;33:1184–1193. © 2011 Wiley‐Liss, Inc.     

Amplitude demodulation of the electrocardiogram signal (ECG) for respiration monitoring and compensation during MR examinations

A method for respiration monitoring during MR-sequences using the electrocardiogram signal (ECG) is presented. The basic principle is known in conventional patient monitoring and is based on the fact that the amplitude of the ECG-signal varies with respiratory motion. A demodulation of this “cardio-respiratory signal” yields a respiration curve that can be used for patient monitoring, triggering, or respiration compensation of MRI sequences. Since no drift is introduced by digital demodulation, this method is superior to analog signal processing. The proposed method was applied during MR examinations using an optically coupled ECG sensor that has the advantage of almost negligible interference due to the MR sequences (<10% of the main ECG signal). The respiration signal obtained is strongly correlated (r = 0.79 to 0.98) with the position of the diaphragm in inferior-superior direction measured during breath-holding MRI.     

基于TMS320VC5402的便携式心电监护仪的研制

目的 研制一种便携性好、功能强大的心电监护仪。方法 以DSP芯片TMS320VC5402为核心,设计硬件系统及控制程序,并嵌入心律失常检测算法。结果 该监护仪能够检测出4种心律失常,存储7段各64k字节的心电信号,还能够为每段存储的心电信号标记采集时间,并能将存储的心电数据以数字和模拟两种方式传送给医院中心站;其功耗低,采用可充电锂离子电池,可以进行连续监护。结论 该监护仪达到设计要求,实用性好。     

基于小波模极大原理的脉象特征提取研究

目的 根据小波分析原理,研究脉象特征提取方法,以有效解决基于时域或频域的传统方法所无法准确提取脉象特征的问题。方法 运用小波模极大方法进行脉象信号周期分割和基本分解,沿时间排列并符号化脉象波上升沿与下降沿的模极大特征点、脉象波谷底和波峰的模极大特征点。结果 确定了不明显的重搏前波、重搏波,以及在主波上升沿和下降沿上出现的不规则脉波,并进一步准确提取了脉象信号的多尺度特征和各种时域特征。结论 采用此方法进行脉象信号的特征点定位并进一步完成特征提取,具有简单、快速、准确等特点,为进一步进行脉象分类识别研究奠定了基础。     

Nontriggered MRI quantification of aortic pulse‐wave velocity

Pulse‐wave velocity is an index of arterial stiffness, which is a strong indicator of cardiovascular risk. We present a high‐speed technique that generates time‐resolved complex difference signal intensity simultaneously in the ascending and descending aorta from velocity‐encoded projections without gating, allowing quantification of pulse‐wave velocity. The velocity‐time curve was approximated with a time‐resolved complex difference signal intensity to estimate the propagation time of the pulse wave in the aortic arch. The path length of the pulse wave is measured from an oblique sagittal image in a plane encompassing thoracic ascending and descending aorta, and pulse‐wave velocity is computed from the ratio between the path length and pulse‐wave propagation time. The method was implemented at 1.5 T and 3 T, and pulse‐wave velocity was quantified in healthy subjects (ages 20–70 years, N = 23) without symptoms or prior history of cardiovascular events. In addition, the method was compared against retrospectively EKG‐gated PC‐MRI. The overall results were found to be in good agreement with literature data showing age‐related increase in aortic stiffness. The RMS differences between the projection and gated PC‐MRI methods were less than 4%. Key benefits of the proposed method are simplicity in both data acquisition and processing requiring only computation of the complex difference between the velocity‐encoded projections rather than absolute velocity. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.     

航天活动各阶段心电图和心动时相的变化及其机理分析

心电图（ＥＣＧ）仍是国外载人航天活动各阶段中连续医学监测的唯一技术。我国载人航天计划中ＥＣＧ也作为重要的医监项目。采用ＥＣＧ,可动态观察人体４大生命体征之一的脉搏（或心率）和心功能,与ＥＣＧ有关的心动进相是反映心功能的一项重要指标,系统了解国外载人航天活动中ＥＣＧ和心动时相的变化及其机理对我国载人航天紧急措施的制定具有重要的参考价值。本文对此作了较系统的回顾与分析。     

冠状动脉搭桥围手术期心电图及心肌酶的变化特点

目的 观察冠状动脉搭桥术（CABG）围手术期心电图（ECG）及心肌酶的变化特点。方法 对41例冠状动脉三支病变行CABA术。术前、后多次描记ECG及抽静脉血进行心肌酶检测。结果 与手术前ECG比较,ST段抬高24人,ST—T改善5人,ST—T变化不明显4人,Q-T间期缩短5人,QRS波幅降低3人。心肌酶正常4人,异常37人。ECG与心肌酶呈同步性改变。当ST段弓背抬高或ST段明显下移或T波到置较深时,心肌酶明显增高;当ST段由弓背抬高变成水平下移或ST段下移减少或T波到置变浅时,心肌酶下降。结论 CABG围手术期ST—T和心肌酶变化特点对了解心肌血供情况有一定的帮助。