基于波形驱动的桡动脉模拟平台设计

为同步获取研究所需的三维脉搏信息和血压波形,通过人体心血管系统循环理论和脉搏波形成机理构建以可编程控制注射泵为核心的桡动脉模拟平台。选择高斯函数模型合成多类型脉搏波编程并驱动平台,由双目视觉脉搏检测系统和压力变送器分别采集模拟桡动脉三维脉搏信息和血压波形,并通过皮尔森相关性检验平台稳定性和可重复性。实验结果表明,桡动脉模拟平台工作稳定可靠、重复性好,可在模拟桡动脉处产生多类型三维脉搏信息和血压波形。该平台结构简单、成本低,产生脉动流类型丰富,为揭示桡动脉三维脉搏信息与血管内压力变化之间的关系以及通过三维脉搏信息预测血压波形提供了一种实验研究平台。     

基于C8051F020单片机的脉搏波信号发生器的设计

目的:设计一种脉搏波信号发生器,能够发出代替人体实际脉搏波的信号,将其发送至各类脉搏波信号检测仪器中,以求调试和检查这类仪器的性能指标。方法:以C8051F020单片机为核心,通过USB接口连接上位机,获得所需的反映人体不同生理状态的脉搏波波形信号并存储,根据用户的不同选择,将脉搏波波形信号发送到指定的仪器上。结果:该脉搏波信号发生器可以方便的接收上位机发来的脉搏波波形信号,并将脉搏波波形信号储存在自身的Flash芯片中,脉搏波信号发生器可以发送各类脉搏波信号。结论:该脉搏波信号发生器结构简单、体积小,可以方便的发出各种脉搏波波形信号,并且每一种脉搏波信号都反映了人体的不同生理状态,属于专用信号发生器。     

基于嵌入式的心血管血流参数检测系统

设计了一种新型的便携式脉搏波信号检测系统。该系统以S3C44BOX处理器为核心,利用光电传感器从指端拾取容积脉搏波,通过对该波形的分析,提取各种参数,同时可以实现对每位受检测对象的脉搏波波形以及参数进行实时地显示。最终将嵌入式实时操作系统μC/OS-Ⅱ移植到S3C44BOX处理器上,使得该系统体积小、无创、检测方便、操作简单,不仅可以应用于临床,更适合社区以及家庭使用。     

利用LMS算法处理血氧饱和度监测中的脉搏波信号

血氧饱和度是反映血液中氧含量的重要参数,它的准确监测对于生理研究及医学应用都具有重要的意义.目前对血氧饱和度的无创监测通常是以识别脉搏波并提取其特征值为基础的双波长法,所以,准确识别脉搏波并在相应周期内提取脉搏波峰-峰值,是计算血氧饱和度的基础.由于得到的脉搏波信噪比较低,因此,正确识别脉搏波波形对于准确地测量血氧饱和度是至关重要的.本文利用最小均方（LMS）自适应算法处理脉搏波信号,取得了比较理想的降噪效果,从而大大提高了脉搏波的正确检出率.     

脉搏波时域特征与血压相关性的研究

目的基于脉搏波的原理和动脉弹性腔理论,研究脉搏波的时间参数、面积参数、主波高度、上升沿平均斜率等参数与血压之间的相关性,确定出相关性较好的参数,为利用脉搏波特征参数检测血压提供理论依据。方法通过高血压患者口服降压药;健康个体运动改变血压,在相同时间间隔内,采集血压以及对应时刻的脉搏波,分析脉搏波时域特征参数与血压之间的相关性。结果血压与脉搏波主峰高度H、波形特征量K、面积参数和时间参数线具有较好的相关性。结论血压与脉搏波特征参数之间存在特定的相关关系,提供了利用脉搏波特征参数检测血压的理论依据。     

桡动脉触力传感器和脉象仪动态性能检测装置的研制

依据桡动脉触力传感器动态性能检测和中医脉图波形的技术要求,提出了一种既能产生具有标准信号源的锯齿波、正弦波和方波,用于检测桡动脉触力传感器性能,又能产生仿真中医脉图波形输出,用于检测脉象仪动态性能的检测装置。该装置覆盖了桡动脉脉搏波触力传感器、脉象诊断仪的静态和动态性能检测的全部要求,从而改变了以往用阶跃信号进行传感器频响计算的局面。     

指端脉搏波检测与频域分析实验设计

目的 本文介绍了一种人体脉搏信号检测并进行频域分析的实验技术、频域分析的应用。方法 设计了一种无创伤脉搏信号检测器，提取理想的脉搏信号，再利用生理机能实验系统进行频域分析。结果 获得了指端脉搏波的功率谱图。结论 指端脉搏频域分析结果对健康普查、心血管系统疾病的检测有重要的实用参考价值，为科学的诊断提供很好的信息来源。     

基于UMPC的无创妊娠期高血压疾病监测系统的设计

目的：设计一款基于UMPC的无创妊娠期高血压疾病监测系统,以帮助医护人员预测孕产妇罹患妊娠期高血压疾病的风险,降低其发病率。方法：设计小型化的脉搏波采集装置,获得孕妇的桡动脉脉搏波,应用UMPC对脉搏波波形进行分析处理计算,求出各项心血管血流动力学参数,通过血流动力学参数预测妊娠期高血压疾病。结果：结合脉搏波无创血流动力学检测理论和数字信号处理技术设计的妊高病监测系统可以预测筛查妊娠期高血压疾病。结论：经过临床实验证实,应用桡动脉脉搏波预测妊娠期高血压疾病是行之有效的,该无创妊娠期高血压疾病监测系统易于携带、方便检测,不仅适用于医院等大型医疗机构,亦适用于孕妇在家庭的医疗保健。     

基于SPCE061A脉搏测量仪的设计与实现

目的：设计一种主要用于临床上检测脉搏的脉搏测量仪。方法：采用光电传感器检测脉搏信号,通过放大、滤波、整形电路将脉搏波信号转换为方波信号,SPCE061A单片机对转换后的方波信号进行检测并计算每分钟脉搏数,最后通过液晶显示脉搏测量值。结果：该测量仪能够在误差小于±1%的条件下对脉搏进行测量。结论：该测量仪能够实时、连续地对脉搏进行准确监测,可以满足临床对脉搏测量的需要,同时也可以为家庭提供帮助。     

腕部气囊式脉搏波自动采集装置的研制

目的:研制一种可以在测量血压的同时采集脉搏波信号并得到心血管评价参数的医疗电子仪器,对实现心血管功能日常监测具有重要意义。方法:将气压式传感器采集腕部气囊内压力信号转换为电信号,通过信号处理电路将其分为接近直流的气囊压力信号和脉搏波信号,经过并行模拟数字(A/D)转换后,利用单片机控制气泵和气阀的充气、放气通断,以实时判断气囊压力值和脉搏波波幅,从而计算出平均动脉压,采集桡动脉压力信号。结果:基于示波法血压自动测量方式可根据脉搏波波幅与袖套压力的对应关系确定平均动脉压,并计算得到收缩压和舒张压,在平均动脉压对应的袖套压力状态下采集到人体桡动脉压力脉搏波波形。结论:该装置可提供一种在测得人体腕部血压的同时自动无创的采集脉搏波的方法。     

Computer-assisted diagnostic system based on the analysis of the rhythmic pattern of a radial artery pulse signal]

The paper outlines a computer-aided diagnostic system based on the analysis of the rhythmic pattern of a radial arterial pulse signal and the procedures of its analysis. Basic data on how to implement hardware and software are presented. The results of clinical studies conducted by using the presented system are given.     

The assessment of quality in medical diagnostic tests: a comparison of ROC/Youden and Taguchi methods

Diagnostic tests are widely used in many areas of modern technological society, but they are of particular importance in medicine, where early and accurate diagnosis can decrease morbidity and mortality rates of disease. How the quality of diagnostic information and decisions should be measured in a meaningful way has become increasingly important in recent years as an abundance of new diagnostic tests have been introduced. A number of seemingly independent indices are studied for evaluating diagnostic performance such as the receiver operating characteristic curves and signal-to-noise ratios. Designing robustness into diagnostic tests can only be achieved by minimizing the variation in the total number of false diagnosis. This article has undertaken a comparison of signal-to-noise ratios developed by Taguchi in quality engineering and system performance in manufacturing industry. A hybrid is also computed and its relevance to physicians as an efficient assessment method is proposed and strongly encouraged.     

Comparing and optimizing diagnostic tests: an information-theoretical approach.

An ideal method for assessing performance of non-binary diagnostic tests would specify each test's optimal operating point and would tell a diagnostician which of many tests was the best one to use in a particular clinical situation. This article shows how information theory and receiver operating characteristic (ROC) analysis can be combined to evaluate and compare diagnostic tests at their optimum cutoffs once disease prevalence and test properties are specified. Though it is not appropriate for all clinical situations, the method can be used for most diagnostic tests whenever information is desired for its own sake or when reducing uncertainty is the goal of testing. The method also is appropriate in those situations where benefits and costs cannot be specified precisely enough to permit test optimization based on a balancing of anticipated goods and evils.     

A non-inferiority test for diagnostic accuracy based on the paired partial areas under ROC curves

Non-inferiority is a reasonable approach to assessing the diagnostic accuracy of a new diagnostic test if it provides an easier administration or reduces the cost. The area under the receiver operating characteristic (ROC) curve is one of the common measures for the overall diagnostic accuracy. However, it may not differentiate the various shapes of the ROC curves with different diagnostic significances. The partial area under the ROC curve (PAUROC) may present an alternative that can provide additional and complimentary information for some diagnostic tests which require false-positive rate that does not exceed a certain level. Non-parametric and maximum likelihood methods can be used for the non-inferiority tests based on the difference in paired PAUROCs. However, their performance has not been investigated in finite samples. We propose to use the concept of generalized p-value to construct a non-inferiority test for diagnostic accuracy based on the difference in paired PAUROCs. Simulation results show that the proposed non-inferiority test not only adequately controls the size at the nominal level but also is uniformly more powerful than the non-parametric methods. The proposed method is illustrated with a numerical example using published data.     

Meta-analysis of diagnostic tests with imperfect reference standards.

We present a method to estimate the summary receiver operating characteristic (SROC) curve for combining information on a diagnostic test from several different studies. Unlike previous methods that assume the reference standard to be error free, our approach allows for the possibility of errors in the reference standard, through use of a latent class model. The model provides estimates of the sensitivity and specificity of the diagnostic test and the case prevalence in each study; these parameters can then be used in a meta-analysis, for example, using the regression method proposed by Moses et al., of a measure of test discrimination on a measure of the diagnostic threshold, to fit the SROC. The method is illustrated with an example on Pap smears that shows how adjusting for imperfection in the reference standard typically reduces the scatter of data in the SROC plot, and tends to indicate better performance of the test than otherwise.     

Evaluation of predictive capacities of biomarkers based on research synthesis

The objective of diagnostic studies or prognostic studies is to evaluate and compare predictive capacities of biomarkers. Suppose we are interested in evaluation and comparison of predictive capacities of continuous biomarkers for a binary outcome based on research synthesis. In analysis of each study, subjects are often classified into two groups of the high‐expression and low‐expression groups according to a cut‐off value, and statistical analysis is based on a 2 × 2 table defined by the response and the high expression or low expression of the biomarker. Because the cut‐off is study specific, it is difficult to interpret a combined summary measure such as an odds ratio based on the standard meta‐analysis techniques. The summary receiver operating characteristic curve is a useful method for meta‐analysis of diagnostic studies in the presence of heterogeneity of cut‐off values to examine discriminative capacities of biomarkers. We develop a method to estimate positive or negative predictive curves, which are alternative to the receiver operating characteristic curve based on information reported in published papers of each study. These predictive curves provide a useful graphical presentation of pairs of positive and negative predictive values and allow us to compare predictive capacities of biomarkers of different scales in the presence of heterogeneity in cut‐off values among studies. Copyright © 2016 John Wiley & Sons, Ltd.     

电子病历在临床护理中的应用

电子病历是医院临床信息系统的重要组成部分.从系统构架、系统功能、系统特点及应用效果4个方面介绍了护理电子病历系统,对比传统手写护理文书,电子病历系统带来临床护理质量与效率的提升.     

A new logistic regression approach for the evaluation of diagnostic test results.

The value of a dichotomous diagnostic test is often described in terms of sensitivity, specificity, and likelihood ratios (LRs). Although it is known that these test characteristics vary between subgroups of patients, they are generally interpreted, on average, without considering information on patient characteristics, such as clinical signs and symptoms, or on previous test results. This article presents a reformulation of the logistic regression model that allows to calculate the LRs of diagnostic test results conditional on these covariates. The proposed method starts with estimating logistic regression models for the prior and posterior odds of disease. The regression model for the prior odds is based on patient characteristics, whereas the regression model for the posterior odds also includes the diagnostic test of interest. Following the Bayes theorem, the authors demontsrate that the regression model for the LR can be derived from taking the differences between the regression coefficients of the 2 models. In a clinical example, they demonstrate that the LRs of positive and negative test results and the sensitivity and specificity of the diagnostic test varied considerably between patients with different risk profiles, even when a constant odds ratio was assumed. The proposed logistic regression approach proves an efficient method to determine the performance of tests at the level of the individual patient risk profile and to examine the effect of patient characteristics on diagnostic test characteristics.