利用脉搏波传播时间计算动脉血压的研究

本研究的目的是研究动脉血压和脉搏波传播时间的关系,探讨通过脉搏波传播时间计算动脉血压的可靠性。采用麻省理工学院MIMIC数据库,通过心电和光电容积脉搏波计算得到脉搏波传播时间,通过有创动脉血压获得平均动脉压,使用线性回归方法分段求得脉搏波传播时间和平均动脉压之间的线性方程,应用该方程结合脉搏波传播时间计算动脉血压,并与实际血压比较评价算法的效果。结果表明,脉搏波传播时间和动脉血压存在负相关关系,在一定时间范围内,可通过脉搏波传播时间计算平均动脉压,均方根误差小于5 mmHg。对临床采集数据的分析同样说明,通过脉搏波传播时间计算动脉血压是可行的。     

Calibration Testing of Instruments for Measurement of Arterial Pressure and Heart Rate Using Pulsating Fluid Flow

The literature on the calibration testing of instruments for the measurement of arterial pressure and heart rate using pulsating fluid flow is reviewed. Classification of respective equipment is given.     

Effect of Arterial Blood Pressure Reduction on Renal Hemodynamics in the Developing Lamb

Aperia , A. and P. Herin . Effect of arterial blood pressure reduction on renal hernodynamics in the developing lamb. Acta physiol. scand. 1976. 98. 387–394. The relationship between pressure and flow in the kidney has been examined in 2–9 and 31–48 day old lambs. Renal blood flow (RBF), determined by the microsphere technique, and glomerular filtration rate (GFR) were first studied under control conditions. The abdominal aorta was then constricted above the renal arteries until the pressure ranged between 60 and 70 mmHg, i.e. just below the normal auto-regulatory range, and the hemodynamic recordings were repeated. During control conditions the arterial pressure was lower in the younger (93 mmHg) than in the older lambs (107 mmHg). During aortic constriction total RBF and GFR were reduced. In both age groups GFR was reduced out of proportion to RBF. The sodium excretion fell around 60% in both age groups. The fall in perfusion pressure resulted in a more pronounced blood flow reduction to the outer than to the inner cortical glomerular capillaries. This pressure-induced blood flow redistribution was found in both age groups. The consequences of the pronounced effect of reducing the perfusion pressure to 60–65 mmHg for the young lambs with their basally low arterial blood pressure are discussed.     

Some Physical Properties of the Pulmonary Arterial Bed Deduced from Pulsatile Arterial Flow and Pressure

This study aimed to quantify changes of vascular compliance and resistance of the proximal and the peripheral pulmonary arterial vessels when vascular smooth muscle was stimulated. These above vascular characteristics were derived from registrations of pulsatile pressure and flow in the pulmonary artery (PA). An in situ cat lung preparation was used, with the right heart by-passed by a pulsatile blood pump. Vascular input impedance was derived from PA pulsatile pressure and flow recordings, and impedance characteristics were used for calculation of the variables of a simple lumped analog representation of the arterial bed. PA smooth muscle was stimulated by infusions of collagen suspension, by general hypoxia and by nor-adrenaline injections. Collagen caused 40% reduction of vascular compliance (C), no changes in proximal arterial resistance (Rl) and 18076 increase in peripheral vascular resistance (R2). Hypoxia caused 5096 reduced C, 20% increased R1 and 70% increased R2. Noradrenaline caused 20:6 reduced C and 30 % increased R1 and R2. These results, together with results derived from simulation of the observed impedance changes in a computer model of the lung arterial bed, indicated that collagen infusion elicited contraction of small and medium-sized arteries, with increased arterial volume as result of increased distending pressure. Hypoxia and noradrenaline, seemed both to cause contraction of the total arterial bed. This effect being most pronounced during hypoxia.     

天麻素对动脉血管顺应性以及血流动力学的影响

本文旨在研究天麻素对动脉血管顺应性和血流动力学等的作用。采用改良风箱模型来计算动脉管的顺应性和血管中血流惯性。在静脉注射天麻素前后，分别记录和计算出狗的血压，心输出量，外周阻力，血流惯性以及中央和外周动脉血管的顺应性。结果表明天麻素具有降低血压和外周务管阻力，增加动脉血管中血流惯性，以及中央和外周动脉血管的顺应性等作用。因此，天麻素是一种有效的能够改善由血管顺应性下降所致的高血压－老年性高血压的中     

Technical and Metrological Aspects of Arterial Pressure Measurement Using the Oscillometric Method

The accuracy of arterial pressure (AP) measurement is a critical parameter of noninvasive blood pressure monitors. The procedure of testing of blood pressure monitors is labor-consuming; moreover, it includes human factor as an object of measurement. An alternative method including experimental estimation of errors and distortions is suggested. This is added to the result of measurements of basic elements of the measuring system, which uses an oscillometric method for determining AP.     

模拟颅高压状态下颅内压与股动脉血压的互相关分析

动物实验模拟颅高压,对实验中获得的颅内压和股动脉血压进行互相关分析.实验方法14条犬安置硬膜外球囊并注液制成颅高压模型,通过改变球囊内液体量来改变颅高压的程度和颅内容积,由压力传感器记录相应压力.结果(1)正常情况下,颅内压和股动脉血压的互相关性差,无稳定的动态关系.(2)随着实验进行,出现稳定的动态关系,互相关系数增加至0.8以上;此时时间延迟约为零,逐渐趋于负值.互相关系数和时间延迟的变化预示着颅内状况的改变.     

Flow Imaging and Computing: Large Artery Hemodynamics

The objective of our session at the International Bio-Fluid Mechanics Symposium and Workshop was at the International Bio-Fluid Mechanics Symponium and Workshop to review the state-of-the-art in, and identify future directions for, imaging and computational modeling of blood flow in the large arteries and the microcirculation. Naturally, talks in other sessions of the workshop overlapped this broad topic, and so here we summarize progress within the last decade in terms of the technical development and application of flow imaging and computing, rather than the knowledge derived from specific studies. We then briefly discuss ways in these tools may be extended, and their application broadened, in the next decade. Furthermore, owing to the conceptual division between the hemodynamics of large arteries, and those within the microcirculation, we review these regimes separately: The former here by Steinman and Taylor; and the latter in a separate paper by Cristini.     

An Innovative Method to Measure the Peripheral Arterial Elasticity: Spring Constant Modeling Based on the Arterial Pressure Wave with Radial Vibration

In this study, we propose an innovative method for the direct measurement of the peripheral artery elasticity using a spring constant model, based on the arterial pressure wave equation, vibrating in a radial direction. By means of the boundary condition of the pressure wave equation at the maximum peak, we can derive the spring constant used for evaluating peripheral arterial elasticity. The calculated spring constants of six typical subjects show a coincidence with their proper arterial elasticities. Furthermore, the comparison between the spring constant method and pulse wave velocity (PWV) was investigated in 70 subjects (21–64 years, 47 normotensives and 23 hypertensives). The results reveal a significant negative correlation for the spring constant vs. PWV (correlation coefficient = −0.663, p < 0.001). Multivariate analysis also indicates the same close relationship. Furthermore, within-operator and between-operator analyses show significantly high reproducibility. Therefore, the use of the spring constant method to assess the arterial elasticity is carefully verified, and it is shown to be effective as well as fast. This method should be useful for healthcare, not only in improving clinical diagnosis of arterial stiffness but also in screening subjects for early evidence of cardio-vascular diseases and in monitoring responses to therapy in the future.     

基于压力波的人体脉搏波传播速度无创检测研究

脉搏波传播速度的变化往往是血管弹性程度发生变化的最早体征,因此脉搏波速度的检测对动脉硬化等疾病的诊断有较高的参考价值,其检测精度主要取决于波速参考点的提取算法。在分析实际采集的脉搏压力波信号特征的基础上,对波峰、波足等特征点进行了识别,并提出了一种根据脉搏波前沿内斜率最大值点的个数和位置确定惟一波速参考点的新算法。临床实验证明,新方法能够有效地提取脉搏波速度,有助于动脉血管弹性程度的辅助诊断。     

A Review of Arterial Phantom Fabrication Methods for Flow Measurement Using PIV Techniques

Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality in the western world. In the last three decades, fluid dynamics investigations have been an important component in the study of the cardiovascular system and CVD. A large proportion of studies have been restricted to computational fluid dynamic (CFD) modeling of blood flow. However, with the development of flow measurement techniques such as particle image velocimetry (PIV), and recent advances in additive manufacturing, experimental investigation of such flow systems has become of interest to validate CFD studies, testing vascular implants and using the data for therapeutic procedures. This article reviews the technical aspects of in-vitro arterial flow measurement with the focus on PIV. CAD modeling of geometries and rapid prototyping of molds has been reviewed. Different processes of casting rigid and compliant models for experimental analysis have been reviewed and the accuracy of construction of each method has been compared. A review of refractive index matching and blood mimicking flow circuits is also provided. Methodologies and results of the most influential experimental studies are compared to elucidate the benefits, accuracy and limitations of each method.     

定量分析红花对家兔平均动脉压及肠系膜血液动力学的影响

在平均动脉血压控制下，应用显微录像静画步进和二点光电法同步连续地测量红花对活体家兔肠系膜内径为３０～５０μｍ细动脉内径、血流速度和血管运动的影响。结果发现：红花２００ｍｇ／ｍｌ·ｋｇ组注入后，肠系膜上内径为３０～５０μｍ细动脉口径以及平均动脉压无变化，而血流速度在给药后３０ｓ开始明显加快，持续１．５ｍｉｎ（Ｐ＜０．０５）。于活体显微镜下，在直径３０～５０μｍ细动脉水平证明红花有抑制局部投与去甲肾上腺素诱导血管运动的作用。血管运动被抑制后血流量增加，给去甲肾上腺素前与给红花后其内径粗细对比变化不明显，提示红花的作用本质是抑制去甲肾上腺素引起的血管运动而不是扩张血管     

锥度角对非定常的动脉血流的压力分布的影响

应用Navier-Stokes方程和质量连续原理对具有锥度角的动脉血管中非定常状态下的血液发展流动建立了一组数学模型，采用贝塞尔函数方法进行了解析求解，获得了非定常状态下的动脉血液发展流动的速度分布和压力分布公式。并与定常状态下动脉血管中的血液发展流动做了比较。结果表明，非定常状态下动脉血液发展流动的压力分布和定常状态下的动脉血管中的血液发展流动的压力分布差别很大。     

Usefulness of Ankle-Brachial Index Calculated Using Diastolic Blood Pressure and Mean Arterial Pressure in Predicting Overall and Cardiovascular Mortality in Hemodialysis Patients

No study has investigated the predictive ability of ankle-brachial index (ABI) calculated using diastolic blood pressure (DBP) (ABIdbp) and mean arterial pressure (MAP) (ABImap) for overall and cardiovascular (CV) mortality in hemodialysis (HD) patients. Our study was aimed to investigate the issue. Two hundred and seven routine HD patients were enrolled. ABI values were measured by ABI-form device. During the follow-up period (122 months), 124 of the 207 patients (59.0%) died, and 59 deaths due to CV cause. Multivariate analysis showed that low ABIsbp, ABIdbp, and ABImap were all significantly associated with increased overall (p ≤ 0.015) and CV mortality (p ≤ 0.015) in whole study patients. A subgroup analysis after excluding 37 patients with ABIsbp < 0.9 or > 1.3 found ABIsbp and ABIsbp < 0.9 were not associated with overall and CV mortality. However, ABImap and ABIdbp < 0.87 were significantly associated with overall mortality (p ≤ 0.042). Furthermore, ABIdbp and ABIdbp < 0.87 were significantly associated with CV mortality (p ≤ 0.030). In conclusion, ABIsbp, ABIdbp, and ABImap were all useful in predicting overall and CV mortality in our HD patients. In the subgroup patients with normal ABIsbp, ABIsbp and ABIsbp < 0.9 were not useful to predict overall and CV mortality. Nevertheless, ABImap and ABIdbp < 0.87 could still predict overall mortality, and ABIdbp and ABIdbp < 0.87 could predict CV mortality. Hence, calculating ABI using DBP and MAP may provide benefit in survival prediction in HD patients, especially in the patients with normal ABIsbp.     

Hemodynamics of Blood Pressure Responses During Active and Passive Coping

This laboratory study was designed to address a number of interrelated issues regarding cardiovascular reactivity to psychological stress. One objective was to extend the previous research comparing cardiovascular responses during active versus passive coping, by comparing responses to two task conditions designed to be similar in all ways except the opportunity to make a response influencing the task's outcome. A second objective was to compare responses to two different passive film tasks, which differed in outcome uncertainty and the degree of vicarious active coping achieved through identification with the role portrayed by the actors. A third objective was to evaluate whether individuals are predisposed to exhibit a particular hemodynamic pattern underlying their blood pressure adjustments, independently of the task demands imposed. Ninety healthy young adult male subjects were tested in pairs on a series of tasks that included a competitive reaction-time task, an active as well as a passive phase of a team reaction-time task, and passive viewing of two film segments. The tasks demanding active coping responses tended to raise blood pressure due primarily to an increase in cardiac output, while vascular resistance fell. During passive coping demands cardiac output increased to a lesser extent, but vascular resistance also tended to increase, thereby raising blood pressure by their synergistic effects. However, these patterns were not typical of all participating subjects. On the basis of their cardiac output and vascular resistance responses to the competitive reaction-time task, one third of the subjects were categorized as being high myocardial reactors (n = 30) and another third high vascular reactors (n = 31). Post-hoc analyses of responses to the other tasks, based on these categorizations, indicated that the hemodynamic basis of reactivity is an individual characteristic only partially modified by coping demands. The active/passive coping dimension is discussed both conceptually and in relation to the role of stress in the etiology of hypertension.     

Blood Pressure Control: A Comparison of Feedback and Instructions Using Pulse Wave Velocity Measurements

A comparison was made between blood pressure changes with exteroceptive feedback and simple instructions. Twenty subjects were instructed either to raise or lower pressure for four sessions, while a further 20 were allowed to view an analogue visual display of mean arterial pressure. Pressure changes were continuously monitored with the pulse wave velocity method. When changes were analyzed from the initial baseline, both groups showed divergence between Increase and Decrease over trials, but feedback enhanced control in Increase only. On assessment from the running baseline, feedback control was superior in both direction conditions. This difference may In due to interaction between running baseline changes and experimental conditions. Control by feedback groups deteriorated when feedback was withdrawn. Modifications were accompanied by alterations in heart rate, respiratory activity and movement, although the association was of a gross nature only, being more prominent in increase conditions.     

流体双折射法对动脉分杈部位应力场分布的实验研究

本文利用流体双折射法实验分析了体外动脉分杈模型分杈处应力场的分布。在稳定流低雷诺数下,动脉二维分杈模型分权处的壁面存在剪应力(τ_(max))变化的极值点,其位置随分流比(M_3/M_1)变化有较大变化而与流速关系不大。动脉分权角度、分流比对τ_(max)分布有较大作用。改变下游阻力可改变M_3/M_1,从而达到改变τ_(max)分布的目的。     

血管性头痛与脑动脉血流变化

本文采用TCD技术测定了200例血管性头痛患者的脑动脉血流变化，结果发现，间歇组（100例）平均脑动脉血流速度明显快于发作组（100例），它们之间有非常显著性差异（P＜0．01）。