Impact of wall filter selection on the detection of vasomotor changes in the brachial artery: a pilot study

2009 ◽  
Vol 34 (2) ◽  
pp. 212-215
Author(s):  
Michel J. Johnson ◽  
J. Kevin Shoemaker
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Lower Body Negative Pressure ◽  
High Amplitude ◽  
Surrounding Tissue ◽  
Peripheral Blood Flow ◽  
Low Velocity ◽  
Flow Monitoring ◽  
Ultrasound Assessment ◽  
The Impact

During Doppler ultrasound assessment of blood flow, a wall filter is used to reduce or eliminate high-amplitude, low-velocity signals from the vessel wall and the surrounding tissue. This study investigated the impact of a range of wall filters (22 Hz, 75 Hz, 128 Hz, and 252 Hz) on the accuracy of forearm blood flow monitoring during the sympathoexcitatory application of lower body negative pressure, when peripheral blood flow may decrease substantially. The 252 Hz filter eliminated diastolic flow in 4 of 10 participants. In the remaining participants, the 252 Hz filter minimized the sensitivity of the pulsatility index. The interpretation of physiological responses could ultimately be compromised by using filters beyond 128 Hz.

Interactions between local and reflex influences on human forearm skin blood flow

1976 ◽  
Vol 41 (6) ◽  
pp. 826-831 ◽  
Author(s):  
J. M. Johnson ◽  
G. L. Brengelmann ◽  
L. B. Rowell
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Forearm Blood Flow ◽  
Lower Body Negative Pressure ◽  
Muscle Blood Flow ◽  
Whole Body ◽  
Vasoconstrictor Response ◽  
Human Forearm ◽  
Forearm Skin ◽  
Forearm Muscle

A three-part experiment was designed to examine interactions between local and reflex influences on forearm skin blood flow (SkBF). In part I locally increasing arm skin temperature (Tsk) to 42.5 degrees C was not associated with increases in underlying forearm muscle blood flow, esophageal temperature (Tes), or forearm blood flow in the contralateral cool arm. In part II whole-body Tsk was held at 38 or 40 degrees C and the surface temperature of one arm held at 38 or 42 degrees C for prolonged periods. SkBF in the heated arm rose rapidly with the elevation in body Tsk and arm Tsk continued to rise as Tes rose. SkBF in the arm kept at 32 degrees C paralleled rising Tes. In six studies, SkBF in the cool arm ultimately converged with SkBF in the heated arm. In eight other studies, heated arm SkBF maintained an offset above cool arm SkBF throughout the period of whole-body heating. In part III, local arm Tsk of 42.5 degrees C did not abolish skin vasoconstrictor response to lower body negative pressure. We conclude that local and reflex influences to skin interact so as to modify the degree but not the pattern of skin vasomotor response.

Peripheral blood flow monitoring in an infant with septic shock

2014 ◽  
Vol 56 (5) ◽  
pp. 787-789 ◽  
Author(s):  
Akio Ishiguro ◽  
Sayaka Sakazaki ◽  
Ryuta Itakura ◽  
Sumie Fujinuma ◽  
Shuntaro Oka ◽  
...  
Keyword(s):  
Septic Shock ◽  
Blood Flow ◽  
Peripheral Blood ◽  
Peripheral Blood Flow ◽  
Flow Monitoring

Comparison of two indices for forearm noradrenaline release in humans

2000 ◽  
Vol 99 (5) ◽  
pp. 363-369 ◽  
Author(s):  
Gerard A. RONGEN ◽  
Jacques W. M. LENDERS ◽  
Paul SMITS ◽  
John S. FLORAS
Keyword(s):  
Blood Flow ◽  
Sodium Nitroprusside ◽  
Noradrenaline Release ◽  
Negative Pressure ◽  
Forearm Blood Flow ◽  
Lower Body Negative Pressure ◽  
Lower Body ◽  
Release Of Noradrenaline ◽  
Appearance Rate

Although there is as yet no method which measures directly the neuronal release of noradrenaline in humans in vivo, the isotope dilution technique with [3H]noradrenaline has been applied to estimate forearm neuronal noradrenaline release into plasma. Two different equations have been developed for this purpose: one to estimate the spillover of noradrenaline into the venous effluent, and a modified formula (often referred to as the appearance rate) which may reflect more closely changes in the neuronal release of noradrenaline into the synaptic cleft, particularly during interventions that alter forearm blood flow. The present study was performed to compare the effects of two interventions known to exert contrasting actions on neuronal forearm noradrenaline release and forearm blood flow. Intra-arterial infusion of sodium nitroprusside at doses without systemic effect increases forearm blood flow, but not neuronal noradrenaline release. In contrast, lower-body negative pressure at -25 mmHg causes forearm vasoconstriction by stimulating neuronal noradrenaline release. During sodium nitroprusside infusion, forearm noradrenaline spillover increased from 1.1±0.3 to 2.2±1.0 pmol·min-1·100 ml-1 (P < 0.05), whereas the forearm noradrenaline appearance rate was unchanged. Lower-body negative pressure did not affect the forearm noradrenaline spillover rate, but increased the forearm noradrenaline appearance rate from 3.4±0.4 pmol·min-1·100 ml-1 at baseline to 5.0±0.9 pmol·min-1·100 ml-1 (P < 0.05). These results indicate that the noradrenaline appearance rate provides the better approximation of changes in forearm neuronal noradrenaline release in response to stimuli which alter local blood flow.

scholarly journals Thermography Quantification of Human Perfusion Thermal Signature

2018 ◽  
Author(s):  
Abbas K. AlZubaidi ◽  
Ahmed F. Hussein ◽  
Mena Basil ◽  
Qais Ahmed Habash
Keyword(s):  
Blood Flow ◽  
Infrared Thermography ◽  
Blood Perfusion ◽  
Bioheat Transfer ◽  
Thermal Excitation ◽  
Thermal Imager ◽  
Flow Monitoring ◽  
Air Stream ◽  
Measurement Protocol ◽  
The Impact

Blood perfusion quantification is important vital parameters in different diagnostic procedure, using infrared thermography imaging; it is reliable to use this technique as non-contact, non-invasive blood flow measurement method. Therefore, we developed a measurement protocol for blood flow over the arm's anterior surface. By using the superficial brachial and radial veins to be monitored under the impact of cold-excitation of (2 &deg;C to 5 &deg;C), the blood perfusion signal was detected using thermal imager of long-wave infrared spectral range (LWIR, 7&mu;m - 14 &mu;m). The simulation of Penne's bioheat transfer equation was performed to be compared with results obtained from the infrared thermography. Furthermore, the proposed blood flow monitoring using external adjusting of the excitation temperature, by using (cold-compress, or cold air-stream) applied to the region under testing. The signal detected resembles to the hemodynamic pulse of the superficial veins, in the definition of systolic and diastolic phases of the cardiac cycle. Moreover, statistical analysis applied to the BFIRT signals from 24 subjects to estimate the skin's mean temperature after recovery from the thermal excitation.

scholarly journals Doppler Ultrasonography of the Fetal Tibial Artery in High-Risk Pregnancy and Its Value in Predicting and Monitoring Fetal Hypoxia in IUGR Fetuses

Medicina ◽  
2021 ◽  
Vol 57 (10) ◽  
pp. 1036
Author(s):  
Kristina Norvilaitė ◽  
Diana Ramašauskaitė ◽  
Daiva Bartkevičienė ◽  
Bronius Žaliūnas ◽  
Juozas Kurmanavičius
Keyword(s):  
Blood Flow ◽  
Stress Test ◽  
Ductus Venosus ◽  
Peripheral Blood Flow ◽  
Fetal Hypoxia ◽  
Doppler Examination ◽  
Flow Monitoring ◽  
Tibial Artery ◽  
Risk Pregnancy ◽  
Flow Changes

Background and Objectives: Intrauterine growth restriction (IUGR) is the term used to describe a fetus whose estimated weight is less than the 10th percentile of its age growth curve. IUGR is the second most common cause of perinatal death. In many cases there is a deficiency in the standardization of optimal management, prenatal follow-up and timing of delivery. Doppler examination is the most sensitive test that can assess the condition of the fetus and indicate fetal intrauterine hypoxia. Numerous studies of the fetal intrauterine state focus on the umbilical artery and the fetal cerebral blood vessels, while the peripheral arteries have so far received insufficient attention. Materials and Methods: We present a case of an IUGR fetus monitored with a non-stress test (NST) and a Doppler examination of the fetal arteries (tibial, umbilical, middle cerebral and uterine) and the ductus venosus. In this case the first early sign of fetal hypoxia was revealed by blood flow changes in the tibial artery. Results: We hypothesize that peripheral vascular changes (in the tibial artery) may more accurately reflect the onset of deterioration in the condition of the IUGR fetus, such that peripheral blood flow monitoring ought to be employed along with other techniques already in use. Conclusion: This paper describes the clinical presentation of an early detection of late IUGR hypoxia and claims that blood flow changes in the tibial artery signal the worsening of the fetus’s condition.

scholarly journals Blood flow in the forearm in patients with Rheumatoid arthritis and healthy subjects under local thermotherapy

2002 ◽  
Vol 58 (2) ◽  
Author(s):  
C. Mucha
Keyword(s):  
Rheumatoid Arthritis ◽  
Blood Flow ◽  
Healthy Subjects ◽  
Forearm Blood Flow ◽  
Human Subjects ◽  
Muscle Blood Flow ◽  
Reactive Hyperemia ◽  
Peripheral Blood Flow ◽  
Healthy Human ◽  
Heat Therapy

Objectives: Muscle blood flow in the forearm of patients with rheuma-toid arthritis and healthy volunteers following treatment with temperature increasingarm baths, mudpacks and short- or decimeter-wave diathermy was studied in thisinvestigation. The aim of the study was to find out the difference of reactive hyperemia between the different temperature methods as well as the influence on theconsensual reaction. Subjects: Eighty patients with rheumatoid arthritis, stage 3 according toSteinbrocker, as well as 80 healthy human subjects had been assigned numerically in the four therapy- and controlgroups. Patients with diseases influencing the peripheral blood flow were excluded. Design: Blood flow was measured by venous occlusion plethysmography in both forearms with the subjects lyingsupine. The application of the local heat therapies had been excluded on the left forearm. The forearm blood flow wasmonitored before heat therapy, directly after as well as in two further 10 minutes intervals. An analysis of variancewas used to determine the influence on blood flow of the response to the heat therapies in patients with rheumatoidarthritis and healthy subjects.Results: Under homogeneous starting conditions and a statistically uniformed high blood flow in rest the reactive values of blood flow on the left-hand side of application and the right consensual side showed high significant differencesbetween all methods of therapy. Differences between the patients and the healthy subjects only showed tendencies withpartially lower reactions, concerning the patients with rheumatoid arthritis. All methods of heat therapy caused a statistically provable consensual reaction that turned out smaller after diathermic methods. Here the post therapeuticreaction of the blood flow on the side of application was also lower or rather shorter. Conclusion: Greater differences of the blood flow in rest between the patients with rheumatoid arthritis and healthysubjects could not be observed. Temperature increasing arm baths and mud packs induced a provable higher increaseof local and consensual forearm blood flow than did diathermic methods. These results lead to the conclusion thatthere are differences in temperature distribution between the methods of therapy. Increasing arm baths and mud packsseem to have a stronger influence on the thermo reflexive skin perfusion.

Aging and the skin blood flow response to the unloading of baroreceptors during heat and cold stress

2004 ◽  
Vol 96 (3) ◽  
pp. 1019-1025 ◽  
Author(s):  
Glaucio Scremin ◽  
W. Larry Kenney
Keyword(s):  
Blood Flow ◽  
Heat Stress ◽  
Cold Stress ◽  
Skin Blood Flow ◽  
Forearm Blood Flow ◽  
Lower Body Negative Pressure ◽  
Older Men ◽  
Stress Conditions ◽  
Vascular Conductance ◽  
Heat And Cold Stress

Control of skin blood flow (SkBF) is on the efferent arm of both thermoregulatory and nonthermoregulatory reflexes. To what extent aging may affect the SkBF response when these two reflex systems interact is unknown. To determine the response of aged skin to the unloading of baroreceptors in thermoneutral, cold stress, and heat stress conditions, sequential bouts of nonhypotensive lower body negative pressure (LBNP) were applied at -10, -20, and -30 mmHg in 14 young (18–25 yr) and 14 older (63–78 yr) men. SkBF was measured by laser-Doppler velocimetry (averaged over 2 forearm sites), and data are expressed as percentage of maximal cutaneous vascular conductance (%CVCmax). Total forearm blood flow was measured by venous occlusion plethysmography, and forearm vascular conductance (FVC) was calculated as the ratio of forearm blood flow to mean arterial pressure. In young men, all three intensities of LBNP in thermoneutrality decreased FVC significantly ( P < 0.05), but FVC at -10 mmHg did not change in the older men. There were no significant LBNP effects on %CVCmax. Application of LBNP during cold stress did not significantly change %CVCmax or FVC in either age group. During heat stress, -10 to -30 mmHg of LBNP decreased FVC significantly ( P < 0.05) in both age groups, but these decreases were attenuated in the older men ( P < 0.05). %CVCmax decreased at -30 mmHg in the younger men only. These results suggest that older men have an attenuated skin vasoconstrictor response to the unloading of baroreceptors in heat stress conditions. Furthermore, the forearm vasoconstriction elicited by LBNP in older men reflects that of underlying tissue (i.e., muscle) rather than that of skin, whereas -30 mmHg LBNP also decreases SkBF in young hyperthermic men.

scholarly journals Sympathetic activation increases NO release from eNOS but neither eNOS nor nNOS play an essential role in exercise hyperemia in the human forearm

2013 ◽  
Vol 304 (9) ◽  
pp. H1225-H1230 ◽  
Author(s):  
Husain Shabeeh ◽  
Michael Seddon ◽  
Sally Brett ◽  
Narbeh Melikian ◽  
Barbara Casadei ◽  
...  
Keyword(s):  
Blood Flow ◽  
Negative Pressure ◽  
Essential Role ◽  
Forearm Blood Flow ◽  
Lower Body Negative Pressure ◽  
No Synthase ◽  
Lower Body ◽  
Sympathetic Activation ◽  
Handgrip Exercise ◽  
No Release

Nitric oxide (NO) release from endothelial NO synthase (eNOS) and/or neuronal NO synthase (nNOS) could be modulated by sympathetic nerve activity and contribute to increased blood flow after exercise. We examined the effects of brachial-arterial infusion of the nNOS selective inhibitor S-methyl-l-thiocitrulline (SMTC) and the nonselective NOS inhibitor NG-monomethyl-l-arginine (l-NMMA) on forearm arm blood flow at rest, during sympathetic activation by lower body negative pressure, and during lower body negative pressure immediately after handgrip exercise. Reduction in forearm blood flow by lower body negative pressure during infusion of SMTC was not significantly different from that during vehicle (−28.5 ± 4.02 vs. −34.1 ± 2.96%, respectively; P = 0.32; n = 8). However, l-NMMA augmented the reduction in forearm blood flow by lower body negative pressure (−44.2 ± 3.53 vs. −23.4 ± 5.71%; n = 8; P < 0.01). When lower body negative pressure was continued after handgrip exercise, there was no significant effect of either l-NMMA or SMTC on forearm blood flow immediately after low-intensity exercise ( P = 0.91 and P = 0.44 for l-NMMA vs. saline and SMTC vs. saline, respectively; each n = 10) or high-intensity exercise ( P = 0.46 and P = 0.68 for l-NMMA vs. saline and SMTC vs. saline, respectively; each n = 10). These results suggest that sympathetic activation increases NO release from eNOS, attenuating vasoconstriction. Dysfunction of eNOS could augment vasoconstrictor and blood pressure responses to sympathetic activation. However, neither eNOS nor nNOS plays an essential role in postexercise hyperaemia, even in the presence of increased sympathetic activation.

Baroreflex function in endurance- and static exercise-trained men

1988 ◽  
Vol 64 (2) ◽  
pp. 585-591 ◽  
Author(s):  
M. L. Smith ◽  
H. M. Graitzer ◽  
D. L. Hudson ◽  
P. B. Raven
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Vascular Resistance ◽  
Forearm Blood Flow ◽  
Lower Body Negative Pressure ◽  
Correlation Coefficients ◽  
Cardiovascular Responses ◽  
Cross Sectional ◽  
Baroreflex Function

The effect of exercise training mode on reflex cardiovascular control was studied in a cross-sectional design. We examined the cardiovascular responses to progressive incremental phenylephrine (PE) infusion to maximal rates of 120 micrograms/min and the delta heart rate/delta blood pressure responses to lower body negative pressure (LBNP) to -50 Torr in 30 men who were either endurance exercise trained (ET), untrained (UT), or weight trained (WT). During PE infusion, measures of blood pressures, forearm blood flow, heart rate and cardiac output, and calculations of forearm vascular resistance, stroke volume, and peripheral vascular resistance were made at each infusion rate when steady-state blood pressure was attained. No significant differences (P less than 0.05) in forearm blood flow or resistance were observed between the groups at any dose of PE, suggesting that the vasoconstrictor response was similar among the groups. Regression analyses of heart rate against mean blood pressure during the PE infusion were performed to evaluate baroreflex function. A linear model was used and correlation coefficients ranging from 0.82 to 0.96 were obtained (P less than 0.05). The slope of the line of best fit for the ET subjects (-0.57) was significantly less (P less than 0.05) than the slopes obtained for either the UT (-0.91) or WT (-0.88) subjects. In addition, the delta heart rate/delta blood pressure measurements obtained during LBNP reflected a similarly significant attenuation of reflex chronotropic control in the ET subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

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