In vivo label-free measurement of blood flow velocity symmetry based on dual line scanning third-harmonic generation microscopy excited at the 1700 nm window

Measurement of bloodflow velocity is key to understanding physiology and pathology in vivo.While most measurements are performed at the middle of the blood vessel,little research has been done on characterizing the instantaneous bloodflow velocity distribution.This is mainly due to the lack of measurement technology with high spatial and temporal resolution.Here,we tackle this problem with our recently developed dual-wavelength line-scan third-harmonic generation(THG)imaging technology.Simultaneous acquisition of dual-wavelength THG line-scanning signals enables measurement of bloodflow velocities at two radially symmetric positions in both venules and arterioles in mouse brain in vivo.Our results clearly show that the instantaneous bloodflow velocity is not symmetric under general conditions.

Changes in mean cerebral blood flow velocity during cognitive task-induced cerebral fatigue in high performance fighter pilots

BACKGROUND： Several studies have demonstrated that sustained cognitive tasks can induce cognitive fatigue and that the mean cerebral blood flow velocity changes in some cerebral regions during cerebral fatigue. OBJECTIVE： To dynamically monitor the changes in mean cerebral blood flow velocity in different brain regions of high performance fighter pilots during mental arithmetic tasks and consecutive performance tasks. DESIGN, TIME AND SETTING： The present neurophysiological trial, based on controlled observation, was performed at the Laboratory of Neurophysiology, Institute of Aviation Medicine, Air Force of China between January 2003 and December 2005. PARTICIPANTS： Forty-five males, high performance fighter pilots, averaging （27.6±2.5） years, were recruited for this study. METHODS： The mean cerebral blood flow velocity in the anterior cerebral artery, middle cerebral artery, and posterior cerebral artery of subjects was dynamically tested using transcranial Doppler during 5- hour mental arithmetic tasks and during 5- hour consecutive performance tasks. The neurobehavioral ability index was analyzed throughout each trial according to the number of correct responses, false responses, and lost responses. Simultaneously, cerebral cognitive fatigue-induced lethargy was assessed by the Stanford Sleepiness Scale. MAIN OUTCOME MEASURES： Changes in mean cerebral blood flow velocity in the anterior cerebral artery, middle cerebral artery, and posterior cerebral artery; neurobehavioral ability index of mental arithmetic and consecutive performance tasks; Stanford Sleepiness Scale scores. RESULTS： During mental arithmetic tasks, the mean cerebral blood flow velocity in the anterior cerebral artery increased during hour 2 and decreased after hour 4. There was no significant change in mean cerebral blood flow velocity in the middle cerebral artery and posterior cerebral artery. During hour 4, cerebral cognitive fatigue was observed and, simultaneously, Stanford Sleepiness Scale scores demonstrated the presence of fatigue. During such a stage, the neurobehavioral ability index decreased, indicating a decline in performance ability. During consecutive performance tasks, the mean cerebral blood flow velocity declined earlier in the posterior cerebral artery compared to the middle cerebral artery. CONCLUSION： Five- hour mental arithmetic tasks have few effects on cerebral functions and do not lead to a significant change in mean cerebral blood flow velocity. Five-hour consecutive performance tasks can induce cerebral cognitive fatigue, and a marked decline in mean cerebral blood flow velocity.

Trans-Thoracic Echocardiographic Aortic Blood Flow Peak Velocity Variation, Distance Minute, Aortic Velocity Time Integral and Postoperative Outcome in Pediatric Surgical Patients—An Observational Pilot Study Protocol

Background: A Randomized Controlled Trial (RCT) has been elaborated where goal directed fluid and hemodynamic therapy (GDFHT) will be realized with trans-thoracic echocardiographic aortic blood flow peak velocity variation (ΔVpeak) and distance minute (DM) to guide fluid therapy and hemodynamics in high risk pediatric surgical patients. This RCT will clarify the impact of GDFHT with ΔVpeak and DM on postoperative outcome in terms of morbidity, length of stay in the intensive care unit (LOSICU), length of mechanical ventilation (LMV) and length of hospital stay (LOS) in children. To determine values of ΔVpeak, DM and VTI predictive of these postoperative outcomes, an observational pilot study will be realized. This pilot study is described here. The primary objective of this study is to determine values of ΔVpeak, DM and ITV predictive of postoperative outcome in children in terms of morbidity. The secondary objectives are to determine values of ΔVpeak, DM and ITV predictive of LOSICU, LMV, LOS, intraoperative, postoperative fluid administration and vasoactive-inotropic therapy. Methods: 500 - 1000 children aged less than 18 years will be included prospectively. Statistic analysis will be realized with XLSTAT 2019.4.2 software or plus. Results and Conclusions: This trial protocol will determine values of ΔVpeak, DM and ITV with echocardiography predictive of postoperative outcome in children.

Optimal velocity encoding during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography

This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-contrast magnetic resonance angiography slice was applied perpendicular to the internal carotid artery and the vertebral artery at C2 level. For each subject, the velocity encoding was set from 30 to 90 cm/s with an interval of 10 cm/s for a total of seven settings. Various velocity encodings greatly affected blood flow volume, maximal blood flow velocity and mean blood flow velocity in the internal carotid artery, but did not significantly affect vertebral arteries and jugular veins. When velocity encoding was 60-80 cm/s, the inflow blood volume was 655 _＋ 118 mL/min, and the outflow volume was 506 _＋ 186 mL/min. The ratio of outflow/inflow was steady at 0.78-0.83, and there was no aliasing in any of the images. These findings suggest that velocity encodings of 60 80 cm/s should be selected during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography.

Influence of High-Velocity Blood Flow on Right-to-Left Shunt in Patients with Patent Foramen Ovale during the Valsalva Maneuver

In this study, we investigated the changes in the right-to-left shunt (RLS) of the patent foramen ovale (PFO) at different phases of the Valsalva maneuver and analyzed the possible mechanisms. The study population consisted of 57 patients with symptoms highly suggestive of a PFO. These patients had been diagnosed with apsychia, migraine with aura, cerebral infarction, transient ischemic attack (TIA), and cerebral ischemia with unknown cause. Routine echocardiography was performed in all patients to rule out a cardiac malformation. Contrast-transcranial Doppler (c-TCD) and contrast-enhanced transthoracic echocardiography (c-TTE) were used to visualize and quantify the RLS. The standard apical four chamber view was used to observe the changes of E peak, A peak, and velocity-time integral (VTI) ratio of tricuspid blood flow during the strain phase and release phase of the Valsalva maneuver. Paired t-test was used to compare E peak, A peak, and VTI ratio of tricuspid blood flow during the different phases. The right-to-left shunt across the PFO (PFO-RLS) was graded in the two phases and compared by Kruskal-Wallis test. Compared with the strain phase of the Valsalva maneuver, the parameters of E, A, and VTI in diastolic period in patients with PFO-RLS at the release phase were significantly increased [54.30 ± 13.65 cm/s vs 100.35 ± 21.11 cm/s, 42.21 ± 12.32 cm/s vs 57.30 ± 18.88 cm/s, 10.34 ± 3.27 cm/s vs 19.58 ± 4.56 cm/s, respectively], and the difference was statistically significant. The positive consequence of PFO-RLS, as diagnosed by c-TTE with the Valsalva maneuver at the release phase of the Valsalva maneuver, was significantly higher than that at the strain phase of the Valsalva maneuver. At the beginning of release phase of the Valsalva maneuver, decreased intrathoracic pressure led to increased venous backflow into the right atrium. Thus, high-velocity blood flow rapidly pushed the PFO open, which resulted in a significant increase in the PFO-RLS. Therefore, the increase of the PFO-RLS during the Valsalva maneuver is caused by the impact of high-velocity blood flow the PFO.

A FREQUENCY DOMAIN QUANTITATIVE MEASUREMENT METHOD FOR BLOOD FLOW VELOCITY WITH BIDIRECTIONAL DOPPLERULTRASOUND AVOIDING DOWN-BAND CHANNEL

ＡＦＲＥＱＵＥＮＣＹＤＯＭＡＩＮＱＵＡＮＴＩＴＡＴＩＶＥＭＥＡＳＵＲＥＭＥＮＴＭＥＴＨＯＤＦＯＲＢＬＯＯＤＦＬＯＷＶＥＬＯＣＩＴＹＷＩＴＨＢＩＤＩＲＥＣＴＩＯＮＡＬＤＯＰＰＬＥＲＵＬＴＲＡＳＯＵＮＤＡＶＯＩＤＩＮＧＤＯＷＮ－ＢＡＮＤＣＨＡＮＮＥＬＷａ...

The Effects of Chinese Medicines on Micro-circulation of Nail Folds and Blood Flow Velocity of Limbs in the Patients with Arteriosclerotic Obliteration

The effects of Chinese medicines on micro-circulation and blood flow velocity in arteries of the lower limbs were observed in 33 patients with arteriosclerotic obliteration (ASO). The results showed that the integral values of micro-circulation after treatment were obviously higher than those before treatment (P<0.05 or P<0.01). Blood flow velocity in arteries of the lower limbs determined with the color Doppler ultrasound detecting method after treatment were also obviously higher than those before treatment (P<0.05 or P<0.01). In this series of 33 ASO patients, the markedly effective rate was 36.36%, and the total effective rate was 63.64%. The observation indicates that the recipe prescribed according to the principle of supplementing qi and activating blood circulation can effectively improve micro-circulation in ASO patients, and accelerate blood flow in arteries of the lower limbs.

Abnormality of peripheral nerve conduction velocity associated with illness course, symptoms and fasting blood glucose in patients with type 2 diabetes mellitus

BACKGROUND: It has shown that abnormality of peripheral nerve conduction velocity during onset of diabetes mellitus is not related to age and sex, but to symptoms, illness course and level of fasting blood glucose. OBJECTIVE: To measure correlation of abnormality of peripheral nerve conduction velocity with various illness courses, symptoms and levels of fasting blood glucose of patients with type 2 diabetes mellitus. DESIGN: Case analysis. SETTING: Department of Neurology, Central People's Hospital of Huizhou. PARTICIPANTS: A total of 128 patients who were diagnosed as type 2 diabetes mellitus were selected from Central People's Hospital of Huizhou from September 2001 to October 2005. There were 75 males and 53 females aged 32-83 years and the illness course ranged from 1 month to 20 years. METHODS: All 128 patients with type 2 diabetes mellitus received neuro-electrophysiological study and their clinical data were retrospectively analyzed to measure peripheral nerve conduction velocity and fasting blood glucose so as to investigate the correlation of peripheral nerve conduction velocity with clinical symptoms, illness course and levels of fasting blood glucose. MAIN OUTCOME MEASURES: Correlation of peripheral nerve conduction velocity with clinical symptoms, illness course and levels of fasting blood glucose. RESULTS: All 128 patients with type 2 diabetes mellitus were involved in the final analysis. ① Among 128 patients, 114 patients had abnormality of peripheral nerve conduction velocity; 110 patients had clinical symptoms, including 102 patients having abnormality of peripheral nerve conduction velocity; 18 patients did not have clinical symptoms, including 12 patients having abnormality of peripheral nerve conduction velocity. There were significant differences between them (χ 2=8.275, P =0.04). ② Among 128 patients, illness course of 75 patients was equal to or less than 5 years, including 27 patients having abnormality of peripheral nerve conduction velocity; illness course of 53 patients was more than 5 years, including 35 patients having abnormality of peripheral nerve conduction velocity. There were significant differences between them (χ 2=11.469, P =0.003). ③ Among 128 patients, levels of fasting blood glucose of 75 patients was equal to or lower than 11 mmol/L, including 41 patients having abnormality of peripheral nerve conduction velocity; levels of fasting blood glucose of 53 patients was higher than 11 mmol/L, including 38 patients having abnormality of peripheral nerve conduction velocity. There were significant differences between them (χ 2=4.023, P =0.134). CONCLUSION: ① Abnormality of peripheral nerve conduction velocity of patients with type 2 diabetes mellitus is related to illness courses and clinical symptoms. The longer the illness course is, the severer the abnormality of peripheral nerve conduction velocity is. Abnormality of peripheral nerve conduction velocity always occurs on patients who have clinical symptoms. ② Abnormality of peripheral nerve conduction velocity is not related to levels of fasting blood glucose.

Wrist blood flow signal-based computerized pulse diagnosis using spatial and spectrum features

ABSTRACT Current computerized pulse diagnosis is mainly based on pressure and photoelectric signal. Considering the richness and complication of pulse diagnosis information, it is valuable to explore the feasibility of novel types of signal and to develop appropriate feature representation for diagnosis. In this paper, we present a study on computerized pulse diagnosis based on blood flow velocity signal. First, the blood flow velocity signal is collected using Doppler ultrasound device and preprocessed. Then, by locating the fiducial points, we extract the spatial features of blood flow velocity signal, and further present a Hilbert-Huang transform-based method for spectrum feature extraction. Finally, support vector machine is applied for computerized pulse diagnosis. Experiment results show that the proposed method is effective and promising in distinguishing healthy people from patients with cho- lecystitis or nephritis.

Possible key residues that determine left gastric artery blood flow response to PACAP in dogs

AIM:To determine the effect of pituitary adenylate cy-clase-activating polypeptide (PACAP) on left gastric artery (LGA) flow and to unveil the structural or functional important sites that may be critical for discrimination of different receptor subtypes. METHODS: Peptides, including PACAP-27, PACAP-38, amino acid substituted PACAP-27 and C-terminus truncated analogues PACAP (27-38), were synthesized by a simultaneous multiple solid-phase peptide synthesizer. Flow probes of an ultrasound transit-time blood flowmeter were placed around the LGA of beagle dogs. Whenpeptides were infused intravenously, the blood flow was measured.RESULTS: [Ala4, Val5]-PACAP-27 caused a concentration-dependent vasodepressor action which was similar to that caused by PACAP-27. The LGA blood flow response to [Ala4, Val5]-PACAP-27 was significantly higher than that to PACAP-27, which was similar to that to vasoactive intestinal polypeptide (VIP) at the same dose. [Ala6]-PACAP-27 did not increase the peak LGA ? ow. [Gly8]-PACAP-27 showed a similar activity to VIP. [Asn24, Ser25, Ile26]-PACAP-27 did not change the activity of peptides at all doses. CONCLUSION: NH2 terminus is more important to biological activity of peptides and specifi c receptor recognition than COOH-terminus.

The Flow Behavior of Red Blood Cell Reduced Deformability in Microchannel

Blood cells are mainly(~99%)comprised of red blood cells.The most remarkable properties of are their high deformability,which allow they flow through microcapillaries of diameter even smaller than their size.The RBC’s remarkable mechanical properties originate from the unique architecture of its membrane.To study the mechanism of RBC’s deformability,a commonly adopted approach is to localize the cytoskeleton protein by immunofluorescence,followed by exploring the changes of cytoskeleton protein during cell deformation.During this process,the fixed treatment of RBC using GA and PFA is of great importance.However,RBC’s deformability is reduced by the fixation process and skeletal protein of membrane is changed accordingly.The flow behavior of red RBCs through the microchannel also changed.Given the difficulty of observing RBC flow in vivo,in vitro simulation by virtue of microfluidic devices provides a feasible alternative.An important physiological phenomenon of the blood flow is the formation of cell free layer(CFL),with RBCs show a tendency to concentrate towards the central axis of the pipeline and move faster than the plasma layer.However,this phenomena is weaken if the stiffness of the membrane increase,which occurs in some disease,such as hereditary spherocytosis and hereditary elliptocytosis.To study the effects of GA and PFA fix treatment on RBC deformability,a microfluidic platform is employed to measuring the CFL and flow velocity of blood flow in this work.The PDMS micro flow channel used is 100 micrometers in width and 50 micrometers in deep.The RBC suspension is fed into the flow channel by the injection pump(NE-1000.USA),and the experiments are observed and recorded by the inverted microscope(IX70,Olympus,Japan)and high-speed camera(Memrecam GX-1,NAC,Japan)system.Three GA concentrations,i.e.,0.000 5,0.000 75,and 0.001 wt.%were used.Meanwhile,the effect of PFA at a concentration of 2wt.%work with GA was also investigated.Images of the flowing RBCs are processed mainly based on Memrecam GXLink.The results show that,the diameter of the RBC be treated is bigger and the shape of the RBC is became more flat after treated.Some of RBCs lost their biconcave structure.When the RBC suspension with 5%Hct flow in the microchannel,the CFL thickness decrease after being treated.And with concentrations of GA increase,the CFL thickness become thinner.The CFL thickness decrease significantly when GA and 2 wt.%PFA work combined.The velocity of RBCs decreases after treated with the GA or/and 2wt.%PFA.GA is known to relieve the dissolution of red blood cells during fluorescence labeling.On the other hand,the crosslinking of the aldehyde group(-cho)of GA with the amino group(-nh2)of RBC membrane protein will change the conformation of the membrane protein and its visco-elastic properties in turn.Then,the transparent fluidity orrheology characteristics of RBC is altered.Since GA and PFA are commonly used to immobilize red blood cells and keep the fluorescence constant,and PFA works similarly as GA,as a result,the variation of membrane protein conformation is intensified,and the membrane becomes stiffer.

Blood Flow Simulation in the Femoral Artery

This paper presents the development of the blood flow simulation in two dimensions over the real geometry of the femoral artery. The Navier-Stokes equations are solved using the finite element method, to obtain the distributions of the blood pressure and flow velocity in multiple instants of time and different places of the femoral artery and thus determine the current condition of the blood vessels. The velocity field shows a laminar behavior,where, the velocity is higher in the center of the artery and decreases as the blood flow approaches artery walls. In spite of all artery and blood flow properties not being considered, the values of pressure and velocity obtained are within the normal ranges. Finally the model is used to verify if there exist irregularities in the blood flow in both healthy subjects and sick patients.

Cerebral blood flow volume measurements of the carotid artery and ipsilateral branches using two-dimensional phase-contrast magnetic resonance angiography

The optimal velocity encoding of phase-contrast magnetic resonance angiography （PC MRA） in measuring cerebral blood flow volume （BFV） ranges from 60 to 80 cm/s. To verify the accuracy of two-dimensional （2D） PC MRA, the present study localized the region of interest at blood vessels of the neck using PC MRA based on three-dimensional time-of-flight sequences, and the velocity encoding was set to 80 cm/s. Results of the measurements showed that the error rate was 7.0±6.0% in the estimation of BFV in the internal carotid artery, the external carotid artery and the ipsilateral common carotid artery. There was no significant difference, and a significant correlation in BFV between internal carotid artery ＋ external carotid artery and ipsilateral common carotid artery. In addition, the BFV of the common carotid artery was correlated with that of the ipsilateral internal carotid artery. The main error was attributed to the external carotid artery and its branches. Therefore, after selecting the appropriate scanning parameters and protocols, 2D PC MRA is more accurate in the determination of BFV in the carotid arteries.

RETINAL SPECTRAL IMAGING AND BLOOD FLOW MEASUREMENT

Measurement of both oxygen saturation and blood flow in the retinal vessels has proved to give important information about the eye health and the onset of eye pathologies such as diabetic retinopathy.In this study,we present the implementation,on a commercially available fundus camera,of a retinal imager and a retina blood flow velocimeter.The retinal imager uses division of aperture to acquire nine wavelength-dependent sub-images of the retina.Careful consideration is taken to improve image transfer by measuring the optical properties of the fundus camera and modeling the optical train in Zemax.This part of the setup is calibrated with optical phantoms of known optical properties that are also used to build a lookup table(LUT)linking phantom optical properties to measured reflectance.The retina blood flow velocimeter relies on tracking clusters of erythrocytes and uses a fast acquisition camera attached to a zoom lens,with a green illumination LED-engine.Calibration is provided using a calibrated quartz capillary tube and human blood at a known flow rate.Optical properties of liquid phantoms are retrieved from measured reflectance using the LUT,and blood flow measurements in the retina are presented.

Close Correlations Between Carotid Arterial Mean Blood Flow Velocity,Body Mass Index,and Temperature in Normal Individuals

Objective:Assessing carotid and radial pulses is an essential sphygmology method in traditional Chinese medicine(TCM).It is believed in TCM and by doctors that pulse force is markedly linked with the physiological state of a human,including body mass index(BMI)and temperature.However,comprehensive analysis elucidating these potential correlations remains undetermined.Therefore,this investigation aimed to assess the association of pulse strength with human metabolism.Materials and Methods:The mean blood flow velocity(MBFV)of the carotid artery and pulse force of 122 healthy adults included in this investigation were assessed using ultrasound and manual palpation.Their thermal texture map was also acquired.Results:No substantial variation was observed in the carotid arterial MBFV among normal individuals(P>0.05)regardless of body side and gender.However,young individuals had higher blood velocity than middle-aged individuals(P<0.05).Furthermore,it was identified that MBFV was negatively associated with BMI and torso temperature;however,it was positively linked with hand temperature.Conclusions:This investigation revealed that carotid arterial MBFV could indicate the physical state of humans,including BMI and temperature,and therefore,is valuable for elucidating the effect of TCM on yin–yang.The data validated some TCM beliefs and supported the implementation of sphygmology in TCM.

EFFECTS OF ACUPUNCTURE AT FENGCHI POINT (GB 20) ON CEREBRAL BLOOD FLOW

Blood velocity in the vertebral artery and the basilar artery was observed before and after acupuncture at Fengchi point (GB 20) in 97 patients by transcranial Doppler ultrasonic detecting. The results showed that the blood velocity in patients with either high or low blood flow had significant changes after acupuncture (P【 0.001).

颈总动脉流速对创伤合并休克患者容量反应性的评价

目的探讨颈总动脉呼气末及吸气末流速对评估创伤合并休克患者容量反应性的意义。方法前瞻性研究2017年7月—2019年1月上海市浦东新区人民医院重症监护室收治需要机械通气控制呼吸的创伤合并休克患者60例,根据液体复苏后是否具有容量反应性(VR)且扩容前后心输出量(CO)变化是否≥15%将患者分为有反应(VR+组)及无反应(VR-组),各30例。VR+组男性23例,女性7例;年龄18~86岁,平均46.9岁。VR-组男性21例,女性9例;年龄18~90岁,平均46.1岁;采用迈瑞M9便携式多普勒超声取右颈总动脉长轴方向上测量两组患者呼气末最大血流速度(ex-Vmax)、吸气末最大血流速度(in-Vmax)与呼气末平均血流流速(ex-TAmax)、吸气末平均血流流速(in-TAmax),并计算出各自的变异度值:颈总动脉吸呼气末最大血流速度变异度(△Vmax)、吸呼气末平均血流速度变异度(△TAmax),分析不同组别上述数值的变化;绘制受试者工作特征(ROC)曲线,分析以上各项指标在容量反应性评估方面的价值。结果VR+组与VR-组in-Vmax[(71.72±18.67)cm/s vs.(79.47±24.04)cm/s]、in-TAmax[(40.67±11.44)cm/svs.(46.44±15.84)cm/s]比较无明显差异,但ex-Vmax[(61.00±17.84)cm/s vs.(76.86±25.28)cm/s]、ex-TAmax[(34.83±11.01)cm/s vs.(44.66±15.43)cm/s]比较差异有统计学意义(P<0.05)。VR+组与VR-组△Vmax(19.42%±14.18%vs.5.09%±13.59%)、△TAmax(18.19%±11.63%vs.4.29%±7.57%)比较差异有统计学意义(P<0.001)。ex-Vmax与ex-TAmax对创伤合并休克患者容量评估的ROC曲线下面积分别为0.695和0.678,而△Vmax与△TAmax的ROC曲线下面积均>0.800,分别是0.803和0.863,提示△Vmax、△TAmax对于创伤合并休克患者容量的评估更敏感。结论呼气末颈总动脉最大血流流速及平均血流流速、吸呼气末最大血流流速差异度及平均血流流速变异度均可用来评估机械通气创伤合并休克患者的容量反应性,且吸呼气末最大血流流速变异度及平均血流流速变异度对容量反应性的评估效果更佳。

体检人群中超重和肥胖对基底动脉、颈内动脉和椎动脉功能的影响

目的探讨健康体检人群中,体质量指数(BMI)与颅内动脉(基底动脉、颈内动脉和椎动脉)功能的相关性。方法回顾性选取2023年6至8月健康体检者共1169例。收集一般资料、实验室指标以及经颅多普勒数据。依据BMI分为3组:正常组(<24 kg/m^(2))546例、超重组(24~<28 kg/m^(2))484例和肥胖组(≥28 kg/m^(2))139例。比较3组临床特征、实验室指标、颅内动脉血流速度情况。分析BMI与颅内动脉血流速度的相关性,利用多元线性回归及限制性立方条分析BMI与颅内动脉血流速度的关系,并确定颅内动脉血流速度减慢风险增加的临界值。结果与正常组相比,肥胖组和超重组颅内动脉收缩期血流速度、舒张期血流速度和平均血流速度均较低(P<0.05)。多元线性回归分析显示,BMI与颅内动脉收缩期血流速度、舒张期血流速度及平均血流速度呈负相关(P<0.01),与血管搏动指数、阻力指数无相关性(P>0.05)。限制性立方条结果显示,基底动脉和双侧椎动脉血流速度与BMI之间呈线性相关(P>0.05),双侧颈内动脉血流速度与BMI之间呈非线性相关(P<0.05)。结论健康体检人群中BMI与颅内动脉血流速度呈负相关,当BMI超过特定值(24.18~24.26 kg/m^(2))时,颅内动脉血流速度减慢的风险增加。

沙滩椅体位及控制性降压下肩关节手术病人脑氧饱和度与脑部血流速度改变及其对术后神经认知的影响

目的分析沙滩椅体位及控制性降压下肩关节手术中脑氧饱和度(rScO_(2))与脑部血流速度的变化,及其对病人术后神经认知的影响。方法选取拟于本院以沙滩椅体位接受肩关节手术治疗的病人60例,均为美国麻醉医师协会(ASA)分级Ⅰ、Ⅱ级,在静脉全身麻醉及控制性降压干预下,于麻醉前、麻醉并转入沙滩椅体位后5 min、手术开始时以及手术开始后每隔20 min直至手术结束进行rScO_(2)、大脑中动脉血流速度(VMCA)和有创血压(心脏水平和耳道水平)的检测,并记录脑氧欠饱和事件(CDE)的发生。同时,于术前和术后24 h对病人进行神经认知能力测试。结果转入沙滩椅体位后所有病人的rScO_(2)和VMCA相比麻醉前都有所下降。经历CDE的病人耳道水平平均动脉压、rScO_(2)和VMCA均显著低于未经历CDE的病人,并且术后24 h时连线测试成绩也更低,组间差异有统计学意义(P<0.05)。结论对于ASA分级Ⅰ、Ⅱ级病人,沙滩椅体位及控制性降压下肩关节手术中部分病人的rScO_(2)和VMCA较麻醉前显著下降并发生CDE,进而对术后神经认知产生不利影响。