Non-contact determination of arterial blood pressure alterations induced by blood loss using laser irradiation on the common carotid artery

In order to avoid the secondary exposure of medical personnel to toxic materials under biochemical hazard conditions, we have reported a method for non-contact monitoring of heart and respiratory rates, using microwave radar or laser irradiation. In large-scale disasters, it is important to be able to diagnose shock without touching patients. We evaluated a non-contact method of monitoring arterial blood pressure alterations of New Zealand rabbits induced by blood loss, using He-Ne laser reflection on the common carotid artery. PVR was significantly correlated with systolic blood pressure (r = 0.95, p < 0.01), where PV = peak voltage of reflected laser amplitude, and PVR = PV(present moment state)/PV(normal state). The following formula was derived using the least-squares linear fitting: SBP = 69.6 PVR + 8.2, in which SBP is the systolic blood pressure. Before blood withdrawal, the mean blood pressure, heart rate and haematocrit were 68 +/- 3 mmHg, 154 +/- 10 bpm and 40 +/- 2%, respectively. After intervention, the mean blood pressure, heart rate and haematocrit were 38 +/- 5 mmHg, 197 +/- 25 bpm and 30 +/- 2%, respectively. The proposed non-contact method appears promising for future clinical application in determining arterial blood pressure alterations. It is likely to be useful in reducing the risk of secondary exposure to toxic chemicals or infectious organisms in the case of large-scale disasters.     

Complex structure of the common carotid artery of sheep

Background: Mechanical properties of blood vessels are dictated by the vessel wall structure. In many large conduit vessels the tunica media is a sheath of circular musculature and the tunica adventitia a layer of fibrous connective tissue with limited longitudinal extensibility. In contrast, the carotid artery of the sheep displays in each tunica a more complex architecture of muscle and connective tissue. Methods: Vessels collected from ewes were measured and processed for light microscopy and for transmission electron microscopy. Results: Layers of histologically different materials are found within the tunica intima, media and adventitia. (1) The tunica media is made of circumferentially arranged muscle cells markedly different at different depths. In the innermost third of the media. muscle cells are small and with irregular profiles, the cells are widely separated, and the extracellular material is abundant and composed mainly of elastic fibres. In the outermost third, muscle cells are larger and with more regular profiles, the cells are relatively close to each other and the extracellular material is sparse and consists mainly of collagen fibrils. (2) A small number of fibroblasts is found in all parts of the media amongst the preponderant muscle cells. (3) The intima contains fibroblast-like cells and longitudinally arranged muscle cells. (4) The adventitia contains a thick layer of collagen and elastic fibres; external to this, it displays a conspicuous musculature, made of large bundles of longitudinal muscle. Conclusions: The carotid artery of the sheep presents in all three coats of its wall features which are at variance from those in the better known vessels of small laboratory animals. The presence of many layers of material within the wall, the heterogeneity of the tissues found, and the occurrence of an extensive longitudinal musculature, have important effects on the mechanical properties of the vessel. © 1995 Wiley-Liss, Inc.     

The effect of common carotid artery occlusion on blood pressure in the barodenervated cat

A 12% blood pressure elevation was found during common carotid occlusion in the barodenervated, thoracotomised cat under Nembutal anaesthesia. This rise in blood pressure appeared to be the net result of an 18% increase of total peripheral resistance and a concomitant 5% decrease of mean aortic flow.When the occlusions were repeated after ganglionic blockade similar values were found, indicating that the increase in resistance had not resulted from reflex vasoconstriction. To test if this increase of total peripheral resistance was caused by a mechanical exclusion, Ohm's law for parallel resistances was applied to the systemic tree to calculate the rise in resistance due to obstruction of the carotid flow. The results thus obtained matched the observed increase of peripheral resistance.It is concluded that common carotid artery occlusion can be used to test completeness of barodenervation in the cat, if an increase in blood pressure of about 12% is allowed for.     

Arterial baroreflex sensitivity and blood pressure variabilities before and after carotid surgery

Summary Carotid surgery is frequently associated with postoperative blood pressure alterations. The role of baroreceptors with regard to these alterations was assessed in 50 patients by determining the pre- and postoperative mechanoreceptor sensitivity after Valsalva maneuver and intravenous injections of angiotensin and nitroglycerine as described by Smyth, Sleight and Pickering. In addition, blood pressure was monitored perioperatively and renin and aldosterone levels were measured. In patients with arterial hypertension a postoperative increase of receptor reactivity can be seen necessitating a reduction of antihypertensive therapy in more than 50% of cases. In normotensive patients no uniform response can be observed. A possible explanation for this effect might be the local increase of pressure in the operated vascular segment. The postoperative reintegration of receptor areas which had been adjusted to a reduced pressure level might induce a more sensitive response than can be seen for the remaining receptors, which usually are less responsive in hypertensive patients.     

Objective characterization of the course of the parasellar internal carotid artery using mathematical tools

BACKGROUND: Along the internal carotid artery (ICA), atherosclerotic plaques are often located in its cavernous sinus (parasellar) segments (pICA). Studies indicate that the incidence of pre-atherosclerotic lesions is linked with the complexity of the pICA; however, the pICA shape was never objectively characterized. Our study aims at providing objective mathematical characterizations of the pICA shape. METHODS AND RESULTS: Three-dimensional (3D) computer models, reconstructed from contrast enhanced computed tomography (CT) data of 30 randomly selected patients (60 pICAs) were analyzed with modern visualization software and new mathematical algorithms. As objective measures for the pICA shape complexity, we provide calculations of curvature energy, torsion energy, and total complexity of 3D skeletons of the pICA lumen. We further measured the posterior knee of the so-called "carotid siphon" with a virtual goniometer and performed correlations between the objective mathematical calculations and the subjective angle measurements. CONCLUSIONS: Firstly, our study provides mathematical characterizations of the pICA shape, which can serve as objective reference data for analyzing connections between pICA shape complexity and vascular diseases. Secondly, we provide an objective method for creating such data. Thirdly, we evaluate the usefulness of subjective goniometric measurements of the angle of the posterior knee of the carotid siphon.     

颈动脉粥样硬化与腔隙性脑梗塞患者血压近日节律性的分析

目的：探讨合并颈动脉粥样硬化（CAS）的原发性高血压（EH）患者血压近日节律的特征,及与腔隙性脑梗死（CLI）的关系。方法：高血压患者114名,以彩色多普勒检测患者的颈动脉内膜情况及动态血压仪监测患者24小时血压变化,分为CAS组与CAN（颈动脉正常）组,以差值百分比法分析24小时血压节律变化情况,并进行统计学分析。结果：在CAS组的EH患者中,夜间收缩压和舒张压下降率明显低于CAN组患者（P〈O．05）,发生血压近日节律紊乱的患者明显多于CAN组（P〈O．05）。结论：CAS的发生与EH患者血压近日节律的紊乱有密切关系,是缺血性脑卒中发生的危险因素。     

Snakes based segmentation of the common carotid artery intima media

Ultrasound measurements of the human carotid artery walls are conventionally obtained by manually tracing interfaces between tissue layers. In this study we present a snakes segmentation technique for detecting the intima-media layer of the far wall of the common carotid artery (CCA) in longitudinal ultrasound images, by applying snakes, after normalization, speckle reduction, and normalization and speckle reduction. The proposed technique utilizes an improved snake initialization method, and an improved validation of the segmentation method. We have tested and clinically validated the segmentation technique on 100 longitudinal ultrasound images of the carotid artery based on manual measurements by two vascular experts, and a set of different evaluation criteria based on statistical measures and univariate statistical analysis. The results showed that there was no significant difference between all the snakes segmentation measurements and the manual measurements. For the normalized despeckled images, better snakes segmentation results with an intra-observer error of 0.08, a coefficient of variation of 12.5%, best Bland–Altman plot with smaller differences between experts (0.01, 0.09 for Expert1 and Expert 2, respectively), and a Hausdorff distance of 5.2, were obtained. Therefore, the pre-processing of ultrasound images of the carotid artery with normalization and speckle reduction, followed by the snakes segmentation algorithm can be used successfully in the measurement of IMT complementing the manual measurements. The present results are an expansion of data published earlier as an extended abstract in IFMBE Proceedings (Loizou et al. IEEE Int X Mediterr Conf Medicon Med Biol Eng POS-03 499:1–4, 2004).     

Noninvasive blood pressure measurement on the temporal artery using the auscultatory method

Blood pressures in the temporal artery of five normotensive subjects were recorded using a modified auscultatory setup. The setup comprised a pediatric cuff to occlude the artery and a piezoelectric contact microphone to record the Korotkoff sounds. Both the cuff and microphone were held in their respective positions with an adjustable head band. The recordings were taken under four different conditions: the subject lying supine, the subject sitting at rest, the subject sitting immediately after exercise and the subject moving the head gently. These recordings were compared with readings from the brachial artery, obtained with a commercially available automatic blood pressure measuring device. Korotkoff sounds were analyzed in the time and frequency domain. Results indicate that Korotkoff sounds in the temporal artery are much smaller in amplitude, and do not exhibit the same distinctive phases as those of the brachial artery. Despite these differences, these sounds can be used to detect blood pressures at head level. The accuracy of the readings was within ±10%. Successful readings were also obtained with gentle head motions, demonstrating that this setup has the potential to be developed into an ambulatory blood pressure monitoring system.     

Time course of arterial repair following endothelial denudation in the rat carotid artery

Summary Repair processes in the intima and media of the rat carotid artery were studied morphometrically for time intervals of up to 28 days after injury induced by air-drying. Air-drying injury included endothelial denudation as well as medial necrosis.Repair was most rapid between days 9 and 11 after injury as regards the increase in myointimal lesion size, the extent of repopulation of the media and re-endothelialization. After day 11, myointimal lesion size continued to increase until day 28. Medial repair, however, almost completely ceased at day 11, 25% of the inner media and 5% of the outer media remaining necrotic. At day 21, the vessels were almost completely re-endothelialized; however, even at day 28, about 10% of the middle of the vessel was still permeable to Evans Blue.The response of Sprague Dawley rats to injury differed from that of Wistar rats. Compared with Wistar rats, Sprague Dawley rats showed larger myointimal lesions, less medial necrosis and slower endothelial repair. It is suggested that the extent of medial necrosis and the speed of endothelial regeneration affect the arteriosclerotic response in rats     

Geometry of the human common carotid artery. A vessel cast study of 86 specimens

The carotid artery is of special interest for the pathologist because of its frequent depositions, and for the fluidmechanician because of its complex flow properties. However, there is a distinct lack in current knowledge of its geometry. Therefore, a vessel cast study was undertaken. At post mortem, the arteries are excised and filled with a special resin at the proper transmural pressure. Eighty-six vessel casts of the carotid artery were performed, and some etiological factors of atherosclerosis, such as age, sex and disease, were collected. The following selected geometric parameters of these vessel casts were measured in this study: the diameters of the main branches of carotid bifurcation (common, internal and external arteries), and the angles between internal, external and common carotid arteries. The averaged geometric parameters and their variability over 86 vessel casts of the carotid artery were investigated. Furthermore, the relationship between these measured parameters and the etiological factors age, sex and disease was analyzed. The geometric parameters varied considerably, presumably contributing to a corresponding variability in the local hemodynamic and distribution of the atherosclerotic lesions.     

增强型体外反搏增加心脏骤停犬颈总动脉血流量

目的: 探讨增强型体外反搏(EECP)干预对心脏骤停(SCA)犬颅内压(ICP)、脑灌注压(CPP)和右颈总动脉平均流量(MQ)的影响。方法: 12只犬制成SCA模型,经心肺复苏至自主循环恢复(ROSC)后随机分成对照组(4只)和EECP组(6只),2只建模未成功。EECP组分别行2次1 h EECP干预,观察致颤前后、ROSC后(每1 h)ICP、CPP和MQ的变化,ROSC 6 h后停止监测。结果: 平均动脉压(MBP)、收缩期血压峰值(MSP)、ICP、平均脑灌注压(MCPP)和收缩期脑灌注压峰值(SCPP)组间比较差异无统计学意义(P＞0.05);EECP时舒张期血压峰值(MDP)和舒张期脑灌注压峰值(DCPP)明显高于对照组(P<0.05)。EECP组颈总动脉血流阻力在EECP时明显低于对照组(P<0.05)。EECP时MQ明显高于对照组(P<0.05)。结论: EECP并不影响SCA-ROSC模型MBP、MSP、ICP、MCPP和SCPP而是通过增加MDP、DCPP和降低血流阻力等机制来增加颈总动脉的平均血流量。     

丁苯酞联合阿托伐他汀治疗对急性脑梗死患者血脂和颈动脉超声相关指标的影响

目的:分析丁苯酞联合阿托伐他汀治疗对急性脑梗死患者血脂和颈动脉超声相关指标的影响.方法:选取2018年10月～2020年10月我院神经内科收治的65例急性脑梗死患者作为研究对象,按照随机数表法分为常规组(阿托伐他汀治疗,n=31)和治疗组(丁苯酞联合阿托伐他汀治疗,n=34).治疗后比较两组的血脂和颈动脉超声相关指标....     

应用超声射频信号技术软件评估高甘油三脂患者颈动脉结构和功能的早期改变

目的 应用超声射频信号技术评价高甘油三脂血症(HTG)患者颈动脉内中膜厚度及弹性功能早期改变的临床意义.方法 将48例HTG患者(甘油三脂≥1.8 mmol/L)作为受试组,应用超声射频信号血管内中膜厚度定量分析(QIMT)及动脉僵硬度定量分析(QAS)技术,观察颈动脉内中膜厚度(IMT)及弹性指标的改变,包括颈动脉内径(D)、管壁扩张系数(DC)、顺应系数(CC)、弹性系数(α)、弹性系数(β)及脉搏波传播速度(PWV);并将50例健康人作为对照组.分析上述参数在2组间的差别及弹性指标之间的相关性.结果 HTC组的2侧颈动脉IMT、α、β及PWV的弹性指标均高于对照组,DC、CC较对照组降低,其差异有统计学意义(P＜0.05).组内2侧颈动脉弹性指标之间存在差异,CCL＞CCR,αL＞αR,βL＞βR,PWVL＞PWVR.CC与α、β、PWV呈负相关(P＜0.05),α、β、PWV之间呈正相关(P＜0.05).2组颈动脉内径(D)比较差异无统计学意义(P＞0.05).结论 动脉弹性异常早于形态学的改变,应用超声射频信号技术能提供HTG患者早期颈总动脉结构和弹性功能改变的信息,对其临床早期诊疗具有一定意义.     

The diameters of common carotid artery and its branches in newborns

The common carotid artery (CCA) bifurcation is of clinical importance due to its vascular access site for intravascular intervention. Additionally, it is also one of the most common sites of atherosclerotic plaque formation. There are numerous studies on the diameters of CCA, internal carotid artery (ICA), and external carotid artery (ECA) in adults, but few studies on newborns. Cadaver and angiographic studies have shown dimensional variations in the carotid arteries within/between individuals and also between different sexes. It is well known that the initial lesions of atherosclerosis begin very early in fetal life. Therefore, it is important to know the anatomical details of the CCA and its branches. In the present study, the neck regions of 20 (11 males and 9 females) fixed newborn cadavers were dissected. The CCAs were cut below the bulb of the carotid bifurcation further; ICA and ECA were cut above the bulb of the carotid bifurcation. The internal diameters of the CCA, ICA, and ECA were measured using a light microscopy. ECA/CCA, ICA/CCA, ICA/ECA ratios, and outflow to inflow area ratio were calculated. The mean outflow to inflow area ratio was 1.14±0.28. Our results highly correlated with the defined optimal ratio (1.15). The ECA/CCA, ICA/CCA, and ICA/ECA ratios were 0.78±0.12, 0.71±0.13, and 0.93±0.16, respectively. There were no statistically significant differences between male and female and also between right and left sides. These findings are of importance in understanding the anatomy of carotid artery during newborn period.     

喉罩对颈总动脉和颈内动脉血流动力学的影响

目的 研究喉罩对颈总动脉(CCA)和颈内动脉(ICA)内径、血流速率和血流量等血流动力学参数的影响.方法 随机选择择期全麻下行腹腔镜胆囊切除术患者60例,为美国麻醉医师协会(ASA)Ⅰ～Ⅲ级.根据不同年龄分为中青年组(A组,20～59岁)和老年组(B组,60～85岁).按不同的喉罩套囊内压力将A组和B组分为4个亚组,即A1、B1(套囊内压为20～30 cm H2O)(1 cm H2O=0.098 kPa)和A2、B2(套囊内压为40～50 cm H2O),每组15例.所有患者术毕后送入ICU复苏,尚未清醒时拔除气管导管,而后置入喉罩.记录置入喉罩前(T0),置入喉罩后3 min(T1)、10 min(T2)和拔除喉罩后(T3)各时点CCA和ICA的内径、血流速率和血流量等血流动力学参数以及生命体征参数.结果 CCA、ICA的内径和CCA血流量的基础值B组比A组要大(P<0.05).与T0比较,在T1和T2时点,A组和B组CCA内径分别减少9.5%～12.9%和14.5%～24.3%(P<0.05或P<0.01),其中以B2组减少最为显著,A2组和B2组ICA内径分别减少10.9%和16.3%(P<0.05).CCA和ICA的血流速率无明显变化(P>0.05).与T0比较,A组和B组,T1和T2时CCA的血流量分别减少9.3%～10.7%和12.2%～19.1%(P<0.05),其中以B2组减少最为显著,A组和B组ICA血流量分别减少10.0%～13.5%和13.9%～16.6%(P<0.05).在T3时点各观察指标均恢复至T0水平.结论 喉罩通气时,CCA和ICA的内径有所缩小,其血流量相应减少,老年患者减少更为明显,而其血流速率则无明显改变.     

A non-invasive study of alterations of the carotid artery with age using ultrasound images

A region-based method for measurement of arterial diameter to find out the elasticity of the vessel is proposed in this paper. Arterial segments are studied by using images obtained through ultrasound scanning in B-mode. Pulsatile changes of the common carotid artery during diastole and systole are computed. To achieve this, thinned segmentation is done by suitably adjusting the contrast of the image. The diameter changes of the artery wall from the centre of artery are calculated. Fifty-three normal subjects with age group 20–40 years are taken for measurement. Measured diameter is plotted as a graph and pulsatile changes of the artery are obtained. Since no atherosclerotic lesions are detected in the studied subjects, it is suggested that the common carotid artery is a highly compliant artery with a strong alteration of viscoelastic properties with age.     

颈动脉分叉区域的神经血管解剖及其对颈动脉内膜剥脱术的临床意义

目的　通过对尸体标本的颈动脉分叉区域内的神经、血管进行解剖研究,为安全有效地开展颈动脉内膜剥脱术提供形态学依据及解剖学基础。 方法 选取20例（40侧）无明确心、脑血管疾患的尸体解剖标本（男11例、女9例）,采取颈动脉内膜剥脱术式入路对颈动脉分叉区域内的神经、血管进行解剖研究,明确血管和神经的形态学及结构特点。 结果 颈总动脉分叉部形态可分为Ⅰ、Ⅱ、Ⅲ型,分别占比为10%、52.5%、37.5%。分叉位置以甲状软骨为界,左侧颈总动脉分叉部高度在其上缘以上、平上缘和上缘以下的占比分别为55%、37.5%、7.5%;相较之下右侧分别为62.5%、27.5%、10%。男性颈总、颈内、颈外动脉内径均大于女性（P<0.05）;男性颈动脉分叉角度大于女性（P<0.05 ）。双侧颈总、颈内、颈外动脉内径相比无统计学意义（P>0.0 5）;左侧颈动脉分叉角度大于右侧（P<0.05）。 结论　通过对颈动脉分叉区域内的神经、血管进行解剖研究,对颈动脉内膜剥脱术术中血管与神经的保护具有重要的临床意义。     

Nicotine activation of neuronal nitric oxide synthase and guanylyl cyclase in the medulla increases blood flow of the common carotid artery in cats

Individual activation of nicotinic acetylcholine receptor (nAChR) or nitric oxide (NO) synthase in the dorsal facial area (DFA) increases blood flow of common carotid artery (CCA) supplying intra- and extra-cranial tissues. We investigated whether the activation of nAChR initiated the activation of NO synthase and guanylyl cyclase to increase CCA blood flow in anesthetized cats. Microinjections of nicotine (a non-selective nAChR agonist), or choline (a selective α7-nAChR agonist) in the DFA produced increases in CCA blood flow ipsilaterally. These increases were significantly reduced by pretreatment with NG-nitro-arginine methyl ester (l-NAME, a non-specific NO synthase inhibitor), 7-nitroindazole (7-NI, a relatively selective neuronal NO synthase inhibitor) or methylene blue (MB, a guanylyl cyclase inhibitor) but not by that with N5-(1-iminoethyl)-l-ornithine (l-NIO, a potent endothelial NO synthase inhibitor). Control microinjection with d-NAME (an isomer of l-NAME), artificial cerebrospinal fluid or DMSO (a solvent for 7-NI) did not affect resting CCA blood flow, nor did they affect nicotine- or choline-induced response. In conclusion, activation of nAChR, at least α7-nAChR, led to the activation of neuronal NO synthase and guanylyl cyclase in the DFA, which induced an increase in CCA blood flow.     

Non-contact determination of vital sign alterations in hypovolaemic states induced by massive haemorrhage: An experimental attempt to monitor the condition of injured persons behind barriers or under disaster rubble

To assess a non-contact method to determine the physical alteration of human subjects confined behind a barrier or under disaster rubble, an experimental, non-contact monitoring system was tested on rabbits in a hypovolaemic state. New Zealand male rabbits behind a barrier were subjected to hypovolaemic shock induced by the withdrawal of arterial blood (2ml per 100g body weight). The hypovolaemic state was determined by linear discriminant analysis using non-contact-derived variables: heart rate X₁ and respiratory rate X₂. Sixteen rabbits were equally divided between the hypovolaemic and control groups. To obtain the heart and respiratory rates simultaneously, the fast Fourier transform (FFT) was performed on the 1215MHz microwave radar analogue output. The linear discriminant function calculated by non-contact-derived variables was negative in the eight hypovolaemic rabbits and positive in the eight controls, so that the linear discriminant function could distinguish the hypovolaemic group from the control group. The Mahalanobis D-square (an index for classification accuracy) was 5908; the classification error rate corresponding to this value was small and negligible. The hypovolaemic rabbits developed metabolic acidosis (HCO₃ ⁻ 18.6±11.1mmoll⁻¹ and pH 7.15±0.18 in arterial blood). The systolic blood pressure of the hypovolaemic group and the control was 56±4 and 83±6 mmHg, respectively (p<0.01). The proposed method appears promising for applications to monitor the condition of human subjects behind barriers or under disaster rubble.