Blood Flow Acceleration Research Articles

Ameliorative Effect of Exercise Training on Age-Related Vascular and Biochemical Changes in Rats

AbstractBackground: Physical exercise is suggested as a life style modification to improve the age related patho-physiologic heamodynamic alterations.Aim of Study: The present study was designed to evaluate the possible ameliorating role of aerobic exercise training in improving age associated vascular dysfunction and hemody-namic disturbance.Material and Methods: Thirty male albino rats of local strain were used for this study. Rats were divided into three main groups: The young control (aged 3-4 months, weighing 150-200gm) (n=10), aged sedentary (aged 22-24 months, weighing 300-400gm) (n=10) and aged exercised group (aged 22-24 months, weighing 300-400gm) (n=10). Rats in the aged exercised group practiced moderate intensity treadmill exercise for 5 days/week for 6 weeks. After 6 weeks rats were subjected for rat tail-measurement of SBP. Then, fasting retro-orbital blood samples were collected for measuring serum lipid profile (TC, HDL-C, LDL-C, VLDL-C and TGs) and inflammatory cytokine (TNF-a). Lastly, rats were sacrificed and abdominal aorta was exposed for assessing MNV and RP using Doppler ultrasound.Results: In aged sedentary group, there were significant increase in SBP, RP, serum (TC, LDL-C, HDL-C) and serum TNF-a associated with significant decrement in MNV when compared to the corresponding values in the young control ones. Exercise training for six weeks significantly restored age-related vascular and biochemical changes except for HDL-C and TC there was insignificant diffrence when compared to the corresponding values in aged sedentary group.Conclusion: Regular exercise training in aging has a beneficial effect on the cardiovascular functions by accelerating blood flow and decreasing resistance to blood flow, also it has an additive beneficial effect on the associated dyslipidemia and chronic inflammatory state in aging.

THE ROLE OF MYOCARDIAL REVASCULARIZATION IN THE SURVIVAL OF PATIENTS WITH ALTERED CORONARY BLOOD FLOW DETECTED BY TRANSTHORACIC ULTRASOUND

Aim of the study was to identify the effects of myocardial revascularization on the prognosis in patients with altered coronary blood flow detected by transthoracic ultrasound.Material and Methods. Four hundred and twelve (412) patients were included in the study. The inclusion criterion was coronary velocity more than 70 cm/s during echocardiography. The study population was divided into three groups: Group 1 comprised patients with high velocities in the coronary arteries detected by ultrasound, in whom myocardial revascularization was performed; Group 2 comprised patients with high velocities in the coronary arteries, in whom myocardial revascularization was not performed and; the Control Group comprised patients with normal coronary blood flow according to ultrasound. The follow-up period was 10–11 months.Results. Seventeen (17) deaths (4.7%) occurred during follow-up. Death rates were 1.6 vs. 8.1 vs. 0% in Group 1, Group 2 and the Control Group, respectively, with a p-value for the difference between Group 1 and Group 2 (p1) of <0.009; and a p-value for the differences compared with the Control group (р2) of <0.03. Death, myocardial infarction, pulmonary edema, and acute coronary syndrome were observed in 27 patients (7.7% of the study group with accelerated blood flow). The rates of these outcomes were 4.9 vs. 11.0 vs. 0% in Group 1, Group 2, and the Control Group, respectively (p1<0.05; p2<0.006). Discussion. The study showed high rates of mortality or acute coronary events in the group of patients with pathologically high coronary flow velocities. The positive effects of revascularization on survival in this group were verified.Conclusions: 1. Left artery coronary flow velocities over 70 cm/s indicate a high probability of death or acute coronary events within 10.5 months.2. Myocardial revascularization has a significant positive effect on the survival rate and incidence of acute coronary events in patients with coronary artery flow velocities greater than 70 cm/s.3. Patients with high coronary blood flow velocities should be referred to coronary angiography or other diagnostic tests without waiting for clinical manifestations and specific symptoms for coronary artery disease.

THE ROLE OF MYOCARDIAL REVASCULARIZATION IN THE SURVIVAL OF PATIENTS WITH ALTERED CORONARY BLOOD FLOW DETECTED BY TRANSTHORACIC ULTRASOUND

Aim of the study was to identify the effects of myocardial revascularization on the prognosis in patients with altered coronary blood flow detected by transthoracic ultrasound.Material and Methods. Four hundred and twelve (412) patients were included in the study. The inclusion criterion was coronary velocity more than 70 cm/s during echocardiography. The study population was divided into three groups: Group 1 comprised patients with high velocities in the coronary arteries detected by ultrasound, in whom myocardial revascularization was performed; Group 2 comprised patients with high velocities in the coronary arteries, in whom myocardial revascularization was not performed and; the Control Group comprised patients with normal coronary blood flow according to ultrasound. The follow-up period was 10–11 months.Results. Seventeen (17) deaths (4.7%) occurred during follow-up. Death rates were 1.6 vs. 8.1 vs. 0% in Group 1, Group 2 and the Control Group, respectively, with a p-value for the difference between Group 1 and Group 2 (p1) of <0.009; and a p-value for the differences compared with the Control group (р2) of <0.03. Death, myocardial infarction, pulmonary edema, and acute coronary syndrome were observed in 27 patients (7.7% of the study group with accelerated blood flow). The rates of these outcomes were 4.9 vs. 11.0 vs. 0% in Group 1, Group 2, and the Control Group, respectively (p1<0.05; p2<0.006). Discussion. The study showed high rates of mortality or acute coronary events in the group of patients with pathologically high coronary flow velocities. The positive effects of revascularization on survival in this group were verified.Conclusions: 1. Left artery coronary flow velocities over 70 cm/s indicate a high probability of death or acute coronary events within 10.5 months.2. Myocardial revascularization has a significant positive effect on the survival rate and incidence of acute coronary events in patients with coronary artery flow velocities greater than 70 cm/s.3. Patients with high coronary blood flow velocities should be referred to coronary angiography or other diagnostic tests without waiting for clinical manifestations and specific symptoms for coronary artery disease.

Polymorphism A1166C of AGTR1 Gene and the State of Intrarenal Blood Flow in Patients with Essential Arterial Hypertension 1-2 Degrees

to study relationship between genetic disorders and features of intrarenal blood flow in patients with essential arterial hypertension(AH) of 1-2 degree. We examined 100 patients (60 women, 40 men) aged 35 to 58 years with 1-2‑degree essentialarterial hypertension (AH) and chronic kidney disease (CKD) stages I-III. Examination included triplex scanning of renal arterieson the ultrasound scanner Vivid-7 Dimension, genotyping of single-nucleotide polymorphism А1166С of the AGTR1 gene by realtime polymerase chain reaction (PCR), estimation of glomerular filtration rate (GFR) using CKD-EPI formula. Patients were dividedinto 2 groups: group 1 included persons with I and II stage CKD (n=65, 25 men and 40 women), group 2 included patients with stagesIIIA and IIIB CKD (n=35, 15 men and 20 women). Among patients of group 1 prevailed genotype AA, while among group 2patients prevailed genotype AC. Speed of blood flow in interlobar renal arteries was higher in the group 1 compared with group 2, whilein the group 2 time of acceleration of blood flow was higher than in the group 1. The data obtained are indicative of the decreaseof systolic, diastolic, and averaged maximal blood flow velocity and the lengthening of acceleration time in patients with higherCKD stage. The presence in the genotype of patients with 1-2‑degree AH of AGTR1 1166С allele may be considered a riskfactor of early development of CKD. Lowering of speed characteristics of blood flow and lengthening of the acceleration time in patientswith AH can be a criterion of hypertensive nephropathy development.

Kidney damage in essential arterial hypertension: pathogenetic issues for early diagnostics

We review main issues of early diagnostics of kidney damage in patients with essential hypertension. The remodeling of renal vessels and the underlying mechanisms are discussed. The evidence-based data are reviewed to substantiate the use of laboratory methods for the kidney damage diagnostics (calculation of glomerular fltration rate and microalbuminuria). We discuss the role of Doppler methods in the assessment of intrarenal hemodynamics (the resistance index and blood flow acceleration time) for timely detection of changes in renal vessels and the choice of management strategy.

Dynamics of the speed of blood flow in the arteries of the bone regenerate of the limbs and in the brain arteries during functional tests and changes in the treatment mode

The results of a comparative study of the linear velocity of blood flow in the arteries of the bone regenerate in patients with fractures of the leg and shoulder bones and in the process of Ilizarov treatment are analyzed. Studies were conducted at rest and when performing a number of functional tests (orthostatic, muscular and with a dosed axial load on the limb). The effect of stress on the state of regional and cerebral blood flow in the conditions of inpatient treatment and after the transfer of patients to the outpatient treatment regimen was assessed.Material and methods. 41 adult patients with a closed diaphyseal fracture of the humerus and 57 patients with a fracture of the tibia bones during Ilizarov treatment were examined. The blood flow in the regenerate and along the middle cerebral arteries was determined by the method of ultrasonic doppler sonography.Results. With an increase in the functional load on the limb in patients with fractures of the humerus and tibial bones, respectively, up to 10 and 30 kgf, a temporary increase in the blood flow velocity in the arteries of the bone regenerate was observed. Large values of the load on the lower leg, accompanied by the acceleration of blood flow, indicate a better protection of the vascular bed of the tibial regenerate. The magnitude of the decrease in blood flow velocity in the regeneration of the lower leg arising from the behavior of an orthostatic test in the course of treating patients increased from 21 to 37 %, and indicated an increase in the reactivity of the vascular bed. In patients with injuries of the shoulder and lower leg, the transfer to the outpatient treatment regimen was accompanied by a statistically significant (p≤0.001) increase in the duration of the fixation period, respectively, to 82±3 and 94±7 days, a decrease in the increased blood flow velocity in the middle cerebral artery on the contralateral side by 43 % and 57 % and an increase in the magnitude of changes in cerebral blood flow rate during functional muscle test by 50 and 67 %.

Аналіз стану ниркової гемодинаміки у хворих з первинним гіперальдостеронізмом за даними ультразвукового доплерівського сканування

Мета. Проаналізувати стан ниркової гемодинаміки за даними ультразвукового доплерівського сканування у пацієнтів з первинним гіперальдостеронізмом (ПГА).
 Матеріали і методи. У клініці госпітальної хірургії Запорізького державного медичного університету проведено лікування 52 хворих з ПГА. Ультразвукове доплерівське сканування ниркових артерій виконали 18 (34,6%) пацієнтам.
 Результати. У структурі відхилень на рівні стовбура ниркових артерій переважали зниження кінцево-діастолічної швидкості кровообігу, підвищення часу прискорення кровотоку та індексу резистентності, на рівні сегментарних та міжчасткових артерій - показники часу прискорення кровотоку, систоло-діастолічного співвідношення, індексу резистентності та пікового індексу. Встановлений кореляційний зв’язок між діастолічним артеріальним тиском та піковою систолічною швидкістю кровообігу на рівні міжчасткових артерій. Виявлена залежність між рівнем альдостерону та індексом резистентності на рівні стовбура ниркової артерії, систоло-діастолічним співвідношенням та середньою максимальною швидкістю кровотоку на рівні міжчасткової артерії.
 Висновки. ПГА обумовлює зміни пікового індексу, індексу резистентності та систоло-діастолічного співвідношення на всіх рівнях розгалуження ниркових артерій. Рівень альдостеронемії корелює з індексом резистентності на рівні стовбура ниркової артерії, систоло-діастолічне співвідношення та середня максимальна швидкість кровотоку - на рівні міжчасткових артерій.

Quantitative Analysis of Blood Flow in Cerebral Venous Sinus With Stenosis by Patient-Specific CFD Modeling

Hemodynamics analysis of the cerebral venous sinus (CVS) is important to the etiologies of idiopathic intracranial hypertension (IIH) and pulsatile tinnitus (PT). However, the underlying mechanism of the hemodynamics contributing to IIH and PT is still unclear. The aim of this paper is to investigate the hemodynamics of the patient-specific CVS with stenosis by using a computational fluid dynamics analysis. Hemodynamics under the circumstances of different body positions, such as supine, upright, left lateral, and right lateral, was further evaluated for more comprehensive understanding of the impacts of CVS stenosis. Three cases were involved and the patient-specific hemodynamics analysis was performed. Our results showed that the effect of CVS stenosis was dependent on the drainage dominance. CVS stenosis in the collateral branch to the drainage dominance vessel showed a limited effect on the acceleration of blood flow (T1, 163.64%), while a significant increase of velocity was observed in the balance drainage dominance cases (T2, 281.25%). Moreover, body position could be a trigger to the IIH. Our results indicated that the pressure gradient in the CVS shifted along with a different body position. Especially, the average pressure of the CVS increased by 22%, 123.8%, and 45.2% in T1, T2, and T3, respectively, comparing upright position to supine position. Finally, the proposed patient-specific hemodynamics analysis method could reproduce physiological hemodynamics in CVS. The result of this paper could potentially provide further understanding of IIH-related headache and PT.

Effect of temperature and thermal stress on the hemodynamics of the scallop Chlamys farreri, as indicated by Doppler ultrasonography

The effect of temperature and thermal stress on cardiac activity and hemodynamics of a temperate scallop species Chlamys farreri was revealed using Doppler echocardiography. The variation scope of eight hemodynamic parameters within the optimal temperature range (8–26 °C) was determined, including heart beat rate (HR), acceleration of blood flow (ABF), peak systolic velocity (PS), end diastolic velocity (ED), maximum & minimum instantaneous blood flow (Max & Min-IBF), resistive index (RI) and PS/ED.The effects of two thermal stress factors were examined, prolonging high water temperature (28–30 °C) and fast heating (2 °C h−1), on hemodynamics of gill blood vessels. The HR-based Arrhenius break temperatures (ABTs) of the scallop under two stress factors were 29.32 °C and 32.37 °C respectively. Results showed that the scallop has a short-term tolerance to acute thermal stress compared with prolonging high temperature. When temperature rose above 28 °C, the PS/ED ratio and RI exceeded the thresholds of 3.0 and 0.63, respectively, indicating potential damage and malfunction of the blood vessels. Low water temperature (6 °C) may also have negative impacts on blood circulation. When faced with a rapidly rising temperature, the scallop cannot adjust its heartbeat in time, but in compensation, the scallop still supplied sufficient hemolymphs to the gill by expanding the diameter of the arteries. The cause of the scallop's death may be different under two thermal stresses: prolonging high temperature caused cardiac failure and physical damage of the artery, whereas rapid heating caused serious tachycardia accompanied by cardiac failure.

Clinical applicability of monitoring pulmonary artery blood flow acceleration time variations in monitoring fetal pulmonary artery pressure.

In recent years, pulmonary artery blood flow acceleration time (AT) has been believed to be applicable in the examination of fetal lung development. This study aims to evaluate the clinical significance of pulmonary artery blood flow AT as a parameter in monitoring of fetal pulmonary artery pressure. A total of 31 fetuses in midor late-term pregnancy with tricuspid regurgitation were set as the study group (congenital heart disease with a tricuspid regurgitation pressure difference of more than 20 mm Hg was excluded). A total of 68 normal fetuses in midor late-term pregnancy were selected as the control group (strictly screened for tricuspid regurgitation, congenital heart disease and other congenital diseases before inclusion). The average ATs of both groups were calculated. Correlations of pulmonary artery systolic pressure (PASP) and AT, as well as the ratio of AT to right ventricular ejection time (ET) (AT/ET ratio) of both groups were investigated by 1-way analysis of variance (ANOVA). The average AT of the study group was significantly lower than that of the control group (p < 0.0001). In the study group, AT negatively correlated with PASP (r = -0.52; p < 0.01), AT/ET ratio negatively correlated with PASP (r = -0.52; p < 0.01) and both showed statistical significance. The results indicated that fetuses in the study group showed lower ATs and AT/ET ratios than the control group. Acceleration times and AT/ET ratios decreased as PASP increased. Thus, AT and AT/ET ratio can be used clinically as new parameters for the qualitative and - to some extent - quantitative evaluation of fetal pulmonary artery pressure.

Microcirculation in patients with paranoid schizophrenia

To study microcirculation in patients with paranoid schizophrenia by laser Doppler flowmetry. Fifty-three patients at the age from 18 to 38 years with a diagnosis of 'paranoid schizophrenia' (F20.0) were examined in the acute psychotic state and after 3 weeks of therapy. The control group consisted of 20 healthy volunteers. To assess microcirculation, the noninvasive technique of laser Doppler flowmetry using a laser blood flow analyzer was used. Significant changes in the microcirculation persisting even over three weeks of therapy in patients were identified. The total microcirculation index was increased by 1.4 times which indicated the acceleration of blood flow. An increase in the average fluctuations of perfusion by 3.7 times and in the coefficient of variation by 1.9 times, which reflect the excessive strengthening of local mechanisms of regulation of microcirculation, were found. There were an increase in the myogenic tone and neurogenic tone of metarteriole and precapillary sphincters as well as bypass index.

The Computational Fluid Dynamics Analyses on Hemodynamic Characteristics in Stenosed Arterial Models.

Arterial stenosis plays an important role in the progressions of thrombosis and stroke. In the present study, a standard axisymmetric tube model of the stenotic artery is introduced and the degree of stenosis η is evaluated by the area ratio of the blockage to the normal vessel. A normal case (η = 0) and four stenotic cases of η = 0.25, 0.5, 0.625, and 0.75 with a constant Reynolds number of 300 are simulated by computational fluid dynamics (CFD), respectively, with the Newtonian and Carreau models for comparison. Results show that for both models, the poststenotic separation vortex length increases exponentially with the growth of stenosis degree. However, the vortex length of the Carreau model is shorter than that of the Newtonian model. The artery narrowing accelerates blood flow, which causes high blood pressure and wall shear stress (WSS). The pressure drop of the η = 0.75 case is nearly 8 times that of the normal value, while the WSS peak at the stenosis region of η = 0.75 case even reaches up to 15 times that of the normal value. The present conclusions are of generality and contribute to the understanding of the dynamic mechanisms of artery stenosis diseases.

INFLUENCE OF BIO-MOS PROBIOTIC PREPARATION IN THE COMPOSITION OF COMBIQUES ON THE STRUCTURE OF THE KOROSAN AND CHANNEL SOMA KISCHER

INFLUENCE OF BIO-MOS PROBIOTIC PREPARATION IN THE COMPOSITION OF COMBIQUES ON THE STRUCTURE OF THE KOROSAN AND CHANNEL SOMA KISCHER

The impact of temporary clipping during aneurysm surgery on the incidence of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

OBJECTIVE Clipping of a ruptured intracranial aneurysm requires some degree of vessel manipulation, which in turn is believed to contribute to vasoconstriction. One of the techniques used during surgery is temporary clipping of the parent vessel. Temporary clipping may either be mandatory in cases of premature rupture (rescue) or represent a precautionary or facilitating surgical step (elective). The aim of this study was to study the association between temporary clipping during aneurysm surgery and the incidence of vasospasm and delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage (aSAH) in a large clinical series. METHODS Seven hundred seventy-eight patients who underwent surgical aneurysm treatment after aSAH were retrospectively included in the study. In addition to surgical parameters, the authors recorded transcranial Doppler (TCD) sonography-documented vasospasm (TCD-vasospasm, blood flow acceleration > 120 cm/sec), delayed ischemic neurological deficits (DINDs), and delayed cerebral infarction (DCI). Multivariate binary logistic regression analysis was applied to assess the association between temporary clipping, vasospasm, DIND, and DCI. RESULTS Temporary clipping was performed in 338 (43.4%) of 778 patients during aneurysm surgery. TCD sonographic flow acceleration developed in 370 (47.6%), DINDs in 123 (15.8%), and DCI in 97 (12.5%). Patients with temporary clipping showed no significant increase in the incidence of TCD-vasospasm compared with patients without temporary clipping (49% vs 48%, respectively; p = 0.60). DINDs developed in 12% of patients with temporary clipping and 18% of those without temporary clipping (p = 0.01). DCI occurred in 9% of patients with temporary clipping and 15% of those without temporary clipping (p = 0.02). The need for rescue temporary clipping was a predictor for DCI; 19.5% of patients in the rescue temporary clipping group but only 11.3% in the elective temporary clipping group had infarcts (p = 0.02). Elective temporary clipping was not associated with TCD-vasospasm (p = 0.31), DIND (p = 0.18), or DCI (p = 0.06). CONCLUSIONS Temporary clipping did not contribute to a higher rate of TCD-vasospasm, DIND, or DCI in comparison with rates in patients without temporary clipping. In contrast, there was an association between temporary clipping and a lower incidence of DINDs and DCI. There is no reason to be hesitant in using elective temporary clipping if deemed appropriate.

The effect of blood acceleration on the ultrasound power Doppler spectrum

The purpose of the present work was to study the influence of blood acceleration and time window length on the power Doppler spectrum for Gaussian ultrasound beams. The work has been carried out on the basis of continuum model of the ultrasound scattering from inhomogeneities in fluid flow. Correlation function of fluctuations has been considered for uniformly accelerated scatterers, and the resulting power Doppler spectra have been calculated. It is shown that within the initial phase of systole uniformly accelerated slow blood flow in pulmonary artery and aorta tends to make the correlation function about 4.89 and 7.83 times wider, respectively, than the sensitivity function of typical probing system. Given peak flow velocities, the sensitivity function becomes, vice versa, about 4.34 and 3.84 times wider, respectively, then the correlation function. In these limiting cases, the resulting spectra can be considered as Gaussian. The optimal time window duration decreases with increasing acceleration of blood flow and equals to 11.62 and 7.54 ms for pulmonary artery and aorta, respectively. The width of the resulting power Doppler spectrum is shown to be defined mostly by the wave vector of the incident field, the duration of signal and the acceleration of scatterers in the case of low flow velocities. In the opposite case geometrical properties of probing field and the average velocity itself are more essential. In the sense of signal–noise ratio, the optimal duration of time window can be found. Abovementioned results may contribute to the improved techniques of Doppler ultrasound diagnostics of cardiovascular system.

Acceleration of blood flow as an indicator of improved hemodynamics after indirect bypass surgery in Moyamoya disease

Objective: The ultrasonography findings in the superficial temporal artery (STA) in Moyamoya disease patients treated with indirect bypass remain unclear. We evaluated the time-related changes in ultrasonography findings of the STA main trunk and branches in patients with Moyamoya disease who underwent encephalo-duro-arterio-synangiosis (EDAS). Patients and methodsPatients (n=21, 30 sides) with Moyamoya disease who underwent EDAS at Fukuoka University Hospital were prospectively registered between 2008 and 2015. EDAS using the frontal and parietal branches of the STA was adopted in an indirect bypass procedure. Mean velocity (MV) and resistance index (RI) were used as ultrasonography markers, and their changes over time in the STA main trunk and branches were assessed. ResultsThere was a significant increase in MV in both the STA main trunk (p=0.001) and branches (frontal: p=0.005, parietal: p=0.003) at 3 months after EDAS, whereas there was a decrease in RI at 14days after EDAS (main trunk: p <0.001, frontal: p <0.001, parietal: p=0.014). In subgroup analysis of patients divided by EDAS outcome, compared with before EDAS, there were significant differences at 3 months after EDAS in MV (responders: main trunk: p=0.002, frontal: p=0.001, parietal: p=0.001; non-responders: main trunk: p=0.093, frontal: p=0.24, parietal: p=0.96) and RI (responders: main trunk: p<0.001, frontal: p<0.001, parietal: p=0.006; non-responders: main trunk: p=0.17, frontal: p=0.12, parietal: p=0.17). ConclusionsMeasurement of MV may be useful for predicting outcome at 3 months after EDAS.

Non-invasive coronary wave intensity analysis

Wave intensity analysis is calculated from simultaneously acquired measures of pressure and flow. Its mathematical computation produces a profile that provides quantitative information on the energy exchange driving blood flow acceleration and deceleration. Within the coronary circulation it has proven most useful in describing the wave that originates from the myocardium and that is responsible for driving the majority of coronary flow, labelled the backward decompression wave. Whilst this wave has demonstrated valuable insights into the pathogenic processes of a number of disease states, its measurement is hampered by its invasive necessity. However, recent work has used transthoracic echocardiography and an established measures of central aortic pressure to produce coronary flow velocity and pressure waveforms respectively. This has allowed a non-invasive measure of coronary wave intensity analysis, and in particular the backward decompression wave, to be calculated. It is anticipated that this will allow this tool to become more applicable and widespread, ultimately moving it from the research to the clinical domain.

Effects of arterial load variations on dynamic arterial elastance: an experimental study

BackgroundDynamic arterial elastance (Eadyn), the relationship between pulse pressure variation (PPV) and stroke volume variation (SVV), has been suggested as a functional assessment of arterial load. The aim of this study was to evaluate the impact of arterial load changes during acute pharmacological changes, fluid administration, and haemorrhage on Eadyn. MethodsEighteen anaesthetized, mechanically ventilated New Zealand rabbits were studied. Arterial load changes were induced by phenylephrine (n=9) or nitroprusside (n=9). Thereafter, animals received a fluid bolus (10 ml kg−1), followed by stepwise bleeding (blood loss: 15 ml kg−1). The influence of arterial load and cardiac variables on PPV, SVV, and Eadyn was analysed using a linear mixed-effects model analysis. ResultsAfter phenylephrine infusion, mean (sd) Eadyn decreased from 0.89 (0.14) to 0.49 (0.12), P<0.001; whereas after administration of nitroprusside, Eadyn increased from 0.80 (0.23) to 1.28 (0.21), P<0.0001. Overall, the fluid bolus decreased Eadyn [from 0.89 (0.44) to 0.73 (0.35); P<0.01], and haemorrhage increased it [from 0.78 (0.23) to 0.95 (0.26), P=0.03]. Both PPV and SVV were associated with similar arterial factors (effective arterial elastance, arterial compliance, and resistance) and heart rate. Furthermore, PPV was also related to the acceleration and peak velocity of aortic blood flow. Both arterial and cardiac factors contributed to the evolution of Eadyn throughout the experiment. ConclusionsAcute modifications of arterial load induced significant changes on Eadyn; vasodilatation increased Eadyn, whereas vasoconstriction decreased it. The Eadyn was associated with both arterial load and cardiac factors, suggesting that Eadyn should be more properly considered as a ventriculo-arterial coupling index.

Feasibility study for the non-invasive blood pressure estimation based on ppg morphology: normotensive subject study

BackgroundBlood pressure is a critical bio-signal and its importance has been increased with the aged society and the growth of cardiovascular disease population. However, most of hypertensive patients have been suffered the inconvenience in monitoring blood pressure in daily life because the measurement of the blood pressure depends on the cuff-based technique. Nowadays there are many trials to measure blood pressure without cuff, especially, photoplethysmography (PPG) based research is carried out in various ways.MethodsOur research is designed to hypothesis the relationship between vessel wall movement and pressure-flow relationship of PPG and to validate its appropriateness by experimental methods. PPG waveform is simplified by approximate model, and then it is analyzed as the velocity and the acceleration of blood flow using the derivatives of PPG. Finally, we develop pressure index (PI) as an estimation factor of blood pressure by combining of statistically significant segments of photoplethysmographic waveform.ResultsTwenty-five subjects were participated in the experiment. As a result of simulation, correlation coefficients between developed PI and blood pressure were represented with R = 0.818, R = 0.827 and R = 0.615 in systolic blood pressure, pulse pressure and mean arterial pressure, respectively, and both of result showed the meaningful statistically significance (P < 0.05).ConclusionsCurrent study can estimate only the relative variation of blood pressure but could not find the absolute pressure value. Moreover, proposed index has the limitation of diastolic pressure tracing. However, the result shows that the proposed PI is statistically significantly correlated with blood pressures, and it suggests that the proposed PI as a promising additional parameter for the cuff less blood pressure monitoring.

Uterine blood flow in sheep and goats during the peri-parturient period assessed by transrectal Doppler sonography

The aim of the present study was to evaluate uterine blood flow (UBF) during the postpartum period in small ruminants. The study involved measures of UBF in 5 ewes and 5 goats during the first 4 weeks after parturition. Transrectal quantification of UBF was assessed by determining the diameter (DM), time averaged mean velocity (TAMEAN), blood flow volume (BFV), blood flow acceleration (ACCE) and pulsatility index (PI) in the uterine arteries ipsilateral to the previously gravid uterine horn(s) at Wk 20 of gestation and every 3days from the day of parturition (D 0) until Day 27 postpartum (D 27). The diameters of the uterine arteries decreased (P<0.01) in both species during the postpartum period. The results revealed decreases (P<0.0001) in BFV, ACCE and TAMEAN, while PI increased during the postpartum period in both sheep and goats. Furthermore, there were positive correlations (P<0.05) between blood flow parameters in sheep and goats, respectively (BFV and DM, r=0.62 and 0.58; BFV and ACCE, r=0.32 and 0.26; BFV and TAMEAN, r=0.51 and 0.37). There were negative correlations (P<0.05) between PI and other parameters (PI and BFV, r=−0.39 and −0.36; PI and DM, r=−0.54 and −0.24; PI and ACCE, r=−0.58 and −0.48; and PI and TAMEAN, r=−0.80 and −0.79) in sheep and goats, respectively. Altogether, these results indicate that non-invasive Doppler ultrasound parameters provide important information toward understanding changes in the vasculature and its perfusion of the uterus during the postpartum period in sheep and goats.