用自适应AR模型提高血氧饱和度测量中脉搏波信号的检出率

血氧饱和度是人体一项重要的生理参数，它的准确测量对于生理研究及医学应用都具有很重要的意义。对血氧饱和度的无创伤检验通常采用双波长法，在该方法中，血氧饱和度的计算是以识别脉搏波并提取其特征值为基础进行的。由于采用双波长法得到的脉搏波信噪比较低，且脉搏波又不具有明显的特征（例如心电信号中有ＱＲＳ波群），因此常用的脉搏波波形识别方法正确检出率不高，经常出现漏检或误检。本文提出利用时间序列建模的方法，建立     

一种计算脉搏血氧饱和度的新方法

由于常用的计算脉搏血氧饱和度的方法一般都存在测量数据不能实时更新的缺点,本文基于NJL5501R光反射器搭建了脉搏波信号测量的硬件平台,并根据脉搏波信号测量中所采集的红光和红外光具有高度的线性相关性的特点,提出一种通过建立红光和红外光的线性回归模型来确定血氧饱和度值的方法,并且分析了参与计算的脉搏波采样点数多少对脉搏波血氧特征值的影响。实验结果表明,本文提出的方法能够在保证测量精度的同时实现血氧饱和度数据的快速更新,为人体脉搏血氧饱和度实时、准确地监测提供了一种有效的途径。     

脉搏波信号处理的一种简单可靠的实时算法

本文介绍了一种实时处理脉搏波信号的算法。它通过对数字微分信号的特殊处理来实现。经应用在血氧饱和度仪中对光容积脉搏波的处理后，被证明非常可靠。。     

脉搏血氧饱和度检测中自适应滤波消除运动伪差的方法研究

目的研究脉搏血氧饱和度检测系统中运动伪差的消除方法,以提高脉搏血氧仪检测性能。方法通过脉搏血氧仪中的双光束构造噪声参考信号,利用最小均方自适应滤波法消除运动伪差干扰的影响。结果建立了脉搏血氧饱和度检测中消除运动伪差的计算方法,可成功地从运动伪差中提取正常光电容积脉搏波信号作为计算氧饱和度的依据。结论该计算方法简单,可用于实时处理,且测量结果可靠,为进一步抑制脉搏血氧仪噪声奠定了基础。     

脉搏血氧饱和度检测系统设计中干扰信号的处理方法

脉搏血氧饱和度检测系统是一种将血氧浓度的光电检测技术与容积脉搏描记技术结合起来实现无创伤、连续血氧浓度测量的新型医疗监护仪器。消除测量系统中各种干扰的影响,设法正确地检出光电容积脉搏波信号是关键到测量准确性及其精度的关键问题之一。本着重介绍了脉搏血氧饱和度检测系统中干扰的主要来源,处理方法及其应用现状,从而为脉搏血氧饱和度检测系统设计提供了依据。     

脉搏血氧饱和度检测系统设计中干扰信号的处理方法

脉搏血氧饱和度检测系统是一种将血氧浓度的光电检测技术与容积脉搏描记技术结合起来实现无创伤、连续血氧浓度测量的新型医疗监护仪器。消除测量系统中各种干扰的影响 ,设法正确地检出光电容积脉搏波信号是关系到测量系统准确性及其精度的关键问题之一。本文着重介绍了脉搏血氧饱和度检测系统中干扰的主要来源、处理方法及其应用现状 ,从而为脉搏血氧饱和度检测系统设计提供了依据。     

反射式血氧饱和度检测系统研制

反射式血氧仪可以有效避免使用范围受限,但反射式脉搏血氧信号十分微弱,容易受噪声干扰使血氧参数的提取难度加大。为获得高质量有效的反射式容积脉搏波,系统设计中提出一种基于集成芯片AFE4490的脉搏血氧信号检测方案,对比几种基于小波变换的滤波算法去噪效果,完成对血氧信号较优的去噪处理。系统样机经调试后,基本实现反射方式对脉搏血氧饱和度的检测功能。     

线性回归算法提取脉搏血氧特征值初步验证

目的:准确提取脉搏血氧信号特征值R是计算脉搏血氧饱和度的关键。传统的R值提取算法大多采用脉搏波的峰谷值法,需要多个周期的平均来提高精度,存在移动步长难以确定、实时性差等缺点。本文提出一种动态实时的R值提取算法。方法:基于近红外光谱技术(Near infrared spectroscopy,NIRS)的测量原理,建立了红外光(IR)和红光(RD)两束透射光强信号的线性回归模型,并确定回归系数b与特征值R之间的定量关系。以纯数字医用放大器为实验平台,搭建了光源驱动电路和光电检测电路,采集的光电容积脉搏波(Photoplethysmography,PPG)信号由蓝牙USB接口传输至计算机,然后进行线性相关性分析及提取算法验证。结果:分析发现IR和RD两束透射光强信号之间具有很强的相关性(r>0.9),运用线性回归法提取的特征值R可以准确的反映正常血氧饱和度值以及在主动闭气过程中血氧饱和度的下降过程。结论:初步验证结果表明,线性回归算法可以有效的进行脉搏血氧信号特征值的动态估算。     

基于ZigBee的血氧饱和度检测技术与模块研制

目的：为了及时、准确、方便、无约束地检测血氧饱和度,本文研制一种无线血氧饱和度检测模块。方法：结合穿戴式检测技术和ZigBee短距离无线通信技术,设计出基于ZigBee的无线血氧饱和度检测模块。该模块由光电容积脉搏波微型化检测模块、ZigBee接入终端及上位机数据分析处理模块组成,其中数据分析处理采用基于形态匹配的特征提取算法对光电容积脉搏波进行最大值的定位。结果：模块实现的功能有光电容积脉搏波显示,血氧饱和度计算,数据无线传输等。实验表明光电容积脉搏波的最大值检测准确率达到98％,而血氧饱和度的计算误差控制在8．8％以内,满足血氧饱和度的检测要求;此外,ZigBee无线传输技术与光源驱动脉冲调节器均有效减少能量的消耗。结论：本模块设计实现病人的移动监护,具有无线化、低功耗、微型化和高性价比等特点。     

一种同时消除脉搏波信号中呼吸基线漂移和高频噪声的方法

目的：基于光电容积脉搏波可以实现血氧饱和度等人体生理参数的无创检测。基于光电容积脉搏波测量时,由于信号采集过程中存在人体呼吸和仪器本身热噪声等干扰,脉搏波信号中存在着呼吸基线漂移和高频噪声,影响最终的人体生理参数测量精度。方法：因此提出一种在经验模式分解的过程中结合小波变换的方法,来同时消除呼吸基线漂移和高频噪声的影响。首先通过经验模态分解将脉搏波信号分解为若干内在模式分量,并分别判断出含有呼吸基线漂移和代表高频噪声的分量,对于代表高频噪声的分量采用类似小波变换的方法进行滤波,利用小波变换将含有呼吸基线漂移的分量分解,将代表呼吸基线漂移的小波细节置零,信号重构后就达到了同时消除呼吸基线和高频噪声的目的。利用自行研制的测量装置采集的脉搏波信号进行实验验证,并采用信号交直流比R和信号的频谱进行效果评价。结果：有效地同时消除了呼吸基线漂移和高频噪声。结论：该方法将有利于血氧饱和度等人体生理参数无创检测精度的提高。     

The Cardiac and Vascular Components of Pulse Transmission Time: A Computer Analysis of Systolic Time Intervals

Systolic time interval methodology was used to explore the relative contributions of intracardiac and vascular delays to modifications in pulse transmission time elicited by a series of behavioural and physical challenges. The following variables were recorded on every cardiac cycle: interbeat interval (IBI), the interval between Q and R wave of the EKG, Q wave to pulse arrival (QPT) at the ear and wrist, left ventricular ejection time, and cardiac pre-ejection period (PEP). The true arterial pulse transit time (PTT), inversely related to pulse wave velocity, was calculated by subtracting PEP from QPT. Modifications of QPT were generally associated with PEP rather than PTT responses. But QPT to the ear and wrist were not equivalent; PEP showed closer correlations with QPT to the ear, while PTT was correlated more consistently with QPT to the wrist. Similar patterns were observed with monitoring from the Q and R waves of the EKG. Important differences also emerged between individuals in the degree to which QPT reactions were correlated with the cardiac or vascular components. A supplementary analysis of correlations between blood pressure and the components of QPT was carried out through hand-scoring of systolic time intervals. Both PEP and PTT contributed to the correlations of systolic pressure with QPT. The uses of pulse transmission times as indices of pulse wave velocity, or alternatively of PEP and ventricular contractility, are considered.     

A device for increasing the amplitude of the pulse pressure of cerebrospinal fluid

In order to analyze the effect of increasing CSF pulse pressure a device has been designed which delivers to CSF pulsations of variable amplitude and synchronous with the CSF arterial oscillations. The R wave of the ECG triggers a circuit which provides a square wave of adjusted duration and selected delay. This wave drives a unit which controls the power supply to electromagnetic pump.     

Wave superpositioning and the initiation of tooth morphogenesis: An application of the Bandwidth Theorem

The Bandwidth Theorem states that a single significant pulse R(t) of time duration Δt will result from the superpositioning of wave components over a frequency range Δω. A continuous oscillatory source will result in the formation of a wave train with regular peaks of amplitude that decay as a result of random phase differences. It is postulated that such a source of oscillation exists at the mesial end of the jaw, from whence wave trains are initiated that progress distally, where they stimulate competent cells to cross the morphogenic threshold of odontogenesis.     

高血压患者外周血管壁腔比与脉搏传导速度的探讨

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An association between aortic pulse wave velocity,blood pressure and chronic inflammation in ESRD patients on peritoneal dialysis

Increased aortic pulse wave velocity (AoPWV) has been identified as a risk factor for cardiovascular morbidity in the general population and in patients on dialysis. Most of the studies in ESRD patients refer to subjects on hemodialysis. Influence of the inflammatory process on aortic stiffening remains largely unknown. The aim of the present study was to evaluate potential relationships between AoPWV and blood pressure, basic anthropometric parameters, selected growth factors and markers of the inflammatory process in ESRD patients treated with peritoneal dialysis. The study population consisted of 43 patients (19 F, 24 M) with a mean age of 50.6 +/- 13.4 years on PD for a mean period of 21.9 +/- 20.7 months. AoPWV was measured using two pressure transducers placed on the carotid and femoral arteries and connected to an automatic processor (Complion Colson AS, Paris, France). Serum levels of Tumor Necrosis Factor alpha (TNFalpha), interleukin 6 (IL-6) and plasma basic Fibroblast Growth Factor (bFGF) were measured with ELISA; C-reactive protein and fibrinogen with nephelometry. Serum lipid profile was also assessed. Blood pressure was measured in an outpatient department under standardized conditions. Mean aortic pulse wave velocity in the study population was 10.7 +/- 2.1 m/s. No difference in AoPWV was found between men and women. AoPWV correlated significantly with age (R = 0.41; p < 0.01) but not with time on dialysis. Positive relationship between AoPWV and body weight and BMI was shown (R = 0.31; p < 0.05 and R = 0.35; p < 0.05, respectively). AoPWV correlated significantly with systolic blood pressure (SBP), mean arterial pressure (MAP) and pulse pressure (PP) (R = 0.46, p < 0.005, R = 0.46, p < 0.005 and R = 0.43, p < 0.01, respectively). AoPWV correlated with serum IL-6 and plasma bFGF (R = 0.32, p < 0.05 and R = 0.4, p < 0.01; respectively). The correlation with serum CRP was borderline significant (p < 0.53). In multiple regression analysis age (beta 0.38; p < 0.005), plasma bFGF level (beta 0.3; p < 0.05), and systolic blood pressure (beta 0.29; p < 0.05) were independently associated with pulse wave velocity. Our results suggest that AoPWV values in patients on PD are associated with factors similar to those encountered in the general population. We suggest that increased aortic stiffening may also be related to the chronic inflammatory process in PD patients.     

Use of heart rate variability and pulse wave velocity for diagnosing cardiovascular autonomic neuropathy]

Heart rate (HR) and arterial pulse wave velocity (PWV) were used for the evaluation of cardiovascular autonomic neuropathy. Data were analyzed from 30 patients with diabetes mellitus (aged from 13 to 75 years). Twenty healthy male subjects (aged from 22 to 44 years) were analyzed for computing normal values as well. After 15 minutes rest, electrocardiogram (ECG) of lead II and plethysmogram of finger tip were simultaneously recorded for each subject. The recording was first done in supine position for 120 seconds and subsequently in upright position for 40 seconds. HR was computed on the basis of consecutive pairs of R wave of the ECG. PWV was estimated by transit time from R wave peak to initial rise of pulse wave. Mean and coefficient of variation (CV) were obtained from the HR in the supine and upright positions respectively, and also from the PWVs. The influence of changing the position was evaluated by percentage of the difference (increasing rate). All the parameters were statistically tested for the difference between the patients with neuropathy and those without neuropathy. As the result, two parameters, that is, the CV of HR in the supine position and the increasing rate of PWV were found to be useful for diagnosing the cardiovascular autonomic neuropathy (p less than 0.05).     

脉搏波传播和血管顺应性对体循环和肺循环系统血流特性和心室功率的影响

本文采用耦合模型研究脉搏波传播和血管顺应性对体循环和肺循环血流特性和心室功率的影响。左心室和右心室均采用Ｅ－Ｒ模型,后负荷系统对于体动脉和肺动脉分别采用Ｔ－Ｙ管模型和稍微不对称Ｔ管模型,应用脉冲响应法将二者耦合起来。选取生理范围的参数,计算了两个系统的每搏输出量（ＳＶ）、每搏输出功（ＳＷ）、定常功率（Ｗs）、脉动功率（Ｗo)和总功率（Ｗt）等。详细分析了血管顺应性、脉搏波波速等对这些参量的影响。得到的主要结果是脉动功率对参数的变化比定常功率更敏感。因此,脉动功率百分比或许是评估心室效率的一个较好参数之一。     

基于心电信号的脉搏波形特征点提取

为寻求一种精确的脉搏波特征提取方法,提取更多的脉搏波形特征,揭示心电脉搏在时域上的相关性,使用MP425数据采集卡和LabVIEW构成的数据采集系统同步采集ECG信号和脉搏波信号,对ECG信号和脉搏波信号进行分析和处理,采用能量算子法检测心电信号R波;基于同步采集的ECG和脉搏波信号,提出一种应用ECG信号的R波和T波来提取Pulse wave的重搏波和峰值的方法.经过分析与实验验证,该方法能准确找到脉搏波波峰和重搏波位置,并具有较强的抗干扰能力,为研究心电脉搏之间的关系提供了一种新的方法.     

基于神经网络的脉搏波信号血压检测算法

脉搏波信号蕴含大量的人体生理与病理信息,与血压的变化息息相关,利用其特征参数可以无创连续检测血压。神经网络因其极强的学习能力、泛化能力以及可以充分逼近任意复杂的非线性关系而被应用于脉搏波血压提取算法中。本研究介绍了脉搏波特征参数,并简述了基于脉搏波特征参数进行血压测量的研究进展,详细叙述了基于神经网络的脉搏波特征参数血压检测算法,最后对不同神经网络模型的优缺点进行分析,并对基于神经网络的脉搏波特征参数血压监测算法的研究方向进行展望。     

基于超声回波信号的指端脉搏波提取

脉搏波可作为检测人体心血管系统生理病理状态的重要依据。为了验证用超声波测量脉搏波的可能、解决脉搏波的测量部位受限的问题,本研究提出一种从超声回波信号中提取脉搏波的方法。设计一种跟随式超声传感器,用数据采集系统采集指端超声回波信号,经过滤波、选点及小波去噪等处理后得到较为纯净的脉搏波信号;同时采集心电信号以及光电容积脉搏波信号作为参考信号。结果表明,可以从提取的指端脉搏波中准确地获取心率;与同步测得的光电容积脉搏波数据相关系数大部分在0.8以上;波形中的重搏前波、重搏波等细节部分也能明显地表现出来。本研究提出的方法实现了从指端超声回波信号中获取完整可靠的脉搏波信号,为日后获取不同部位的脉搏信号提供了基础。