The purpose of the present study was to investigate the effects of resistance combined with aerobic chrono-exercise on the common carotid artery elasticity and hemodynamics. 24 healthy young men (21.96±0.43 years old) underwent a single acute resistance combined with aerobic exercise intervention at eight time periods (6, 8, 10, 12, 14, 16, 18, and 20 o'clock). The axial flow velocity and diameter waveforms of the common carotid artery were measured, and the hemodynamics were calculated using the classical hemodynamic theory before exercise, immediately after exercise, 10 min and 20 min after exercise. The results showed that during exercise recovery, systolic and mean pressures decreased more markedly after exercise at 8 o'clock (P < 0.05); At 20 min post-exercise, arterial stiffness index and pressure-strain elastic modulus after exercise at 6 o'clock were reduced compared with the resting state, but were significantly elevated after exercise at 20 o'clock (P < 0.05). Immediately after exercise, the pressure rise was higher after exercise at 6 o'clock and the mean wall shear stress was higher after exercise at 20 o'clock (P < 0.05). These results suggest that resistance combined with aerobic chrono-exercise produces different effects on common carotid artery hemodynamics in young men. A single acute session of resistance combined with aerobic exercise at 8 o'clock is more effective in lowering blood pressure. Exercise at 6 o'clock is beneficial to improve arterial elasticity but is not recommended for young male individuals with cardiovascular disease risks because of the excessive increase in blood pressure immediately after exercise. Exercise at 20 o'clock is more effective in improving wall shear stress but is accompanied by elevated arterial stiffness indices and pressure-strain elastic modulus. These results provide a scientific basis for healthy young men in choosing the time of exercise by exploring the common carotid artery elasticity and hemodynamic-related indices.
Humans ; Male ; Young Adult ; Exercise/physiology* ; Carotid Artery, Common/physiology* ; Hemodynamics/physiology* ; Vascular Stiffness/physiology* ; Elasticity ; Resistance Training ; Adult

It has been found that the incidence of cardiovascular disease in patients with lower limb amputation is significantly higher than that in normal people, and the risk of developing coronary atherosclerosis is much higher than that in other high-risk groups. Numerous studies have confirmed that high systolic and diastolic blood pressures are potential risk factors for coronary artery disease, and it has been demonstrated that the ascending aortic pressure during diastole increases after amputation. However, the relationship between lower limb amputation and coronary atherosclerosis has not been fully explained from the perspective of hemodynamic environment. Therefore, in this study, a centralized parameter model of the human cardiovascular system and a three-dimensional model of the left coronary artery were established to investigate the effect of amputation on the hemodynamic environment of the coronary artery. The results showed that the abnormal hemodynamic environment induced by amputation, characterized by factors such as increased diastolic pressure in the ascending aorta, led to a significant expansion of the low wall shear stress (WSS) region on the outer lateral aspect of the left coronary artery bifurcation during diastole. The maximum observed increase in the area of low WSS reached up to 50.5%. This abnormal hemodynamic environment elevates the risk of plaque formation in the left coronary artery. Moreover, the more severe the lower limb atrophy, the greater the risk of coronary atherosclerosis in amputees. This study preliminarily reveals the effect of lower limb amputation on the hemodynamic environment of the left coronary artery.
Humans ; Hemodynamics/physiology* ; Amputation, Surgical/adverse effects* ; Coronary Vessels/physiology* ; Coronary Artery Disease/etiology* ; Lower Extremity/surgery* ; Models, Cardiovascular ; Blood Pressure

INTRODUCTION: Umbilical cord milking (UCM) is a method that allows for postnatal placental transfusion. The benefits of UCM have been demonstrated in some studies, but knowledge about its haemodynamic effects in term infants is limited. The aim of this study was to evaluate the haemodynamic effects of UCM in term infants. METHODS: In this prospective, randomised controlled study, 149 healthy term infants with a birth week of ≥37 weeks were randomly assigned to either the UCM or immediate cord clamping (ICC) group. Blinded echocardiographic evaluations were performed in all the neonates in the first 2-6 h. RESULTS: Superior vena cava (SVC) flow measurements were higher in the UCM group compared to the ICC group (132.47 ± 37.0 vs. 126.62 ± 34.3 mL/kg/min), but this difference was not statistically significant. Left atrial diameter (12.23 ± 1.99 vs. 11.43 ± 1.78 mm) and left atrium-to-aorta diastolic diameter ratio (1.62 ± 0.24 vs. 1.51 ± 0.22) were significantly higher in the UCM group. There were no significant differences in other echocardiographic parameters between the two groups. CONCLUSION We found no significant difference in the SVC flow measurements in term infants who underwent UCM versus those who underwent ICC. This lack of significant difference in SVC flow may be explained by the mature cerebral autoregulation mechanism in term neonates.
Infant, Newborn ; Infant ; Humans ; Pregnancy ; Female ; Infant, Premature/physiology* ; Umbilical Cord Clamping ; Prospective Studies ; Vena Cava, Superior/diagnostic imaging* ; Placenta ; Umbilical Cord/physiology* ; Constriction ; Hemodynamics/physiology*

In recent years, due to the emergence of ultrafast ultrasound imaging technology, the sensitivity of detecting slow and micro blood flow with ultrasound has been dramatically improved, and functional ultrasound imaging (fUSI) has been developed. fUSI is a novel technology for neurological imaging that utilizes neurovascular coupling to detect the functional activity of the central nervous system (CNS) with high spatiotemporal resolution and high sensitivity, which is dynamic, non-invasive or minimally invasive. fUSI fills the gap between functional magnetic resonance imaging (fMRI) and optical imaging with its high accessibility and portability. Moreover, it is compatible with electrophysiological recording and optogenetics. In this paper, we review the developments of fUSI and its applications in neuroimaging. To date, fUSI has been used in various animals ranging from mice to non-human primates, as well as in clinical surgeries and bedside functional brain imaging of neonates. In conclusion, fUSI has great potential in neuroscience research and is expected to become an important tool for neuroscientists, pathologists and pharmacologists.
Animals ; Mice ; Ultrasonography/methods* ; Brain/physiology* ; Magnetic Resonance Imaging ; Optogenetics ; Hemodynamics

Microcirculatory dysfunction is an important pathophysiological change of shock. In the last decade, many researches on the mechanism of microcirculatory dysfunction have been involved in areas such as the glycocalyx damage of vascular endothelial cells, macrocirculation- microcirculation discoupling, vascular hyporeactivity, and microcirculation monitoring. Accordingly, this paper discussed how these research findings can be applied to burn patients, with the aim of alerting the clinicians to improving microcirculation, and maintaining hemodynamic coordination during the treatment of burn shock and burn septic shock. In addition, with the development of accurate and reliable microcirculation monitoring techniques, it is necessary to carry out multi-center clinical trials to reveal the clinical significance of target-oriented shock resuscitation protocol combining macrocirculatory and microcirculatory parameters.
Burns/therapy* ; Endothelial Cells ; Hemodynamics/physiology* ; Humans ; Microcirculation/physiology* ; Resuscitation ; Shock ; Shock, Septic/therapy*

BACKGROUND: It is still unclear what the minimal infusion volume is to effectively predict fluid responsiveness. This study was designed to explore the minimal infusion volume to effectively predict fluid responsiveness in septic shock patients. Hemodynamic effects of fluid administration on arterial load were observed and added values of effective arterial elastance (Ea) in fluid resuscitation were assessed. METHODS: Intensive care unit septic shock patients with indwelling pulmonary artery catheter (PAC) received five sequential intravenous boluses of 100 mL 4% gelatin. Cardiac output (CO) was measured with PAC before and after each bolus. Fluid responsiveness was defined as an increase in CO >10% after 500 mL fluid infusion. RESULTS: Forty-seven patients were included and 35 (74.5%) patients were fluid responders. CO increasing >5.2% after a 200 mL fluid challenge (FC) provided an improved detection of fluid responsiveness, with a specificity of 80.0% and a sensitivity of 91.7%. The area under the ROC curve (AUC) was 0.93 (95% CI: 0.84-1.00, P  < 0.001). Fluid administration induced a decrease in Ea from 2.23 (1.46-2.78) mmHg/mL to 1.83 (1.34-2.44) mmHg/mL (P = 0.002), especially for fluid responders in whom arterial pressure did not increase. Notably, the baseline Ea was able to detect the fluid responsiveness with an AUC of 0.74 (95% CI: 0.59-0.86, P < 0.001), whereas Ea failed to predict the pressure response to FC with an AUC of 0.50 (95% CI: 0.33-0.67, P = 0.086). CONCLUSION: In septic shock patients, a minimal volume of 200 mL 4% gelatin could reliably detect fluid responders. Fluid administration reduced Ea even when CO increased. The loss of arterial load might be the reason for patients who increased their CO without pressure responsiveness. Moreover, a high level of Ea before FC was able to predict fluid responsiveness rather than to detect the pressure responsiveness. TRIAL REGISTRATION ClinicalTrials.gov, NCT04515511.
Cardiac Output/physiology* ; Fluid Therapy ; Gelatin/therapeutic use* ; Hemodynamics ; Humans ; Shock, Septic/therapy*

It has been found that the incidence of cardiovascular disease in patients with lower limb amputation is significantly higher than that in normal individuals, but the relationship between lower limb amputation and the episodes of cardiovascular disease has not been studied from the perspective of hemodynamics. In this paper, numerical simulation was used to study the effects of amputation on aortic hemodynamics by changing peripheral impedance and capacitance. The final results showed that after amputation, the aortic blood pressure increased, the time averaged wall shear stress of the infrarenal abdominal aorta decreased and the oscillatory shear index of the left and right sides was asymmetrically distributed, while the time averaged wall shear stress of the iliac artery decreased and the oscillatory shear index increased. The changes above were more significant with the increase of amputation level, which will result in a higher incidence of atherosclerosis and abdominal aortic aneurysm. These findings preliminarily revealed the influence of lower limb amputation on the occurrence of cardiovascular diseases, and provided theoretical guidance for the design of rehabilitation training and the optimization of cardiovascular diseases treatment.
Amputation ; Aorta, Abdominal/surgery* ; Aortic Aneurysm, Abdominal/surgery* ; Blood Flow Velocity/physiology* ; Hemodynamics/physiology* ; Humans ; Lower Extremity ; Models, Cardiovascular ; Stress, Mechanical

To explore the influence of bionic texture coronary stents on hemodynamics, a type of bioabsorbable polylactic acid coronary stents was designed, for which a finite element analysis method was used to carry out simulation analysis on blood flow field after the implantation of bionic texture stents with three different shapes (rectangle, triangle and trapezoid), thus revealing the influence of groove shape and size on hemodynamics, and identifying the optimal solution of bionic texture groove. The results showed that the influence of bionic texture grooves of different shapes and sizes on the lower wall shear stress region had a certain regularity. Specifically, the improvement effect of grooves above 0.06 mm on blood flow characteristics was poor, and the effect of grooves below 0.06 mm was good. Furthermore, the smaller the size is, the better the improvement effect is, and the 0.02 mm triangular groove had the best improvement effect. Based on the results of this study, it is expected that bionic texture stents have provided a new method for reducing in-stent restenosis.
Bionics ; Computer Simulation ; Coronary Vessels ; Hemodynamics/physiology* ; Models, Cardiovascular ; Stents ; Stress, Mechanical

By using Doppler sensor and pressure sensor, the cerebrovascular stroke detector can be used to measure the blood flow velocity and blood pressure of the carotid artery. In this study, a variety of signal conversion and isolation processing techniques are proposed for processing and feature extraction of the output signals from the sensors. Finally, effective signal output waveforms that can be used to evaluate the cerebrovascular hemodynamics index (CVHI) are obtained, and the sound signal outputs that can reflect the change characteristics of blood flow velocity and blood pressure signals are generated, which realizes the application functional requirements of the detector.
Blood Flow Velocity/physiology* ; Cerebrovascular Circulation/physiology* ; Hemodynamics/physiology* ; Humans ; Stroke ; Technology

Echocardiogram is vital for the diagnosis of cardiac disease. The heart has complex hemodynamics requiring an advanced ultrasound imaging mode. Cardiac ultrasound vector flow imaging is capable of measuring the actual magnitude and direction of the blood flow velocity, obtaining the quantitative parameters of hemodynamics, and then providing more information for clinical research and diagnosis. This study mainly reviewed several different vector flow imaging techniques for cardiac flow and presented the implementation difficulties, and proposed a diverging wave based high frame rate cardiac ultrasound vector flow imaging. The study discussed the limitation of current ultrasound technology used in the cardiac flow measurement, analyzed and demonstrated the specific reasons for these implementation difficulties and the potential future development.
Blood Flow Velocity ; Heart/physiology* ; Hemodynamics ; Ultrasonography