scholarly journals Effects of Wrist Posture and Fingertip Force on Median Nerve Blood Flow Velocity

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Katherine E. Wilson ◽  
Jimmy Tat ◽  
Peter J. Keir
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Median Nerve ◽  
Blood Flow Velocity ◽  
Nerve Blood Flow ◽  
Occupational Risk Factors ◽  
Early Evaluation ◽  
Fingertip Force ◽  
Significant Difference ◽  
Healthy Participants

Purpose. The purpose of this study was to assess nerve hypervascularization using high resolution ultrasonography to determine the effects of wrist posture and fingertip force on median nerve blood flow at the wrist in healthy participants and those experiencing carpal tunnel syndrome (CTS) symptoms. Methods. The median nerves of nine healthy participants and nine participants experiencing symptoms of CTS were evaluated using optimized ultrasonography in five wrist postures with and without a middle digit fingertip press (0, 6 N). Results. Both wrist posture and fingertip force had significant main effects on mean peak blood flow velocity. Blood flow velocity with a neutral wrist (2.87 cm/s) was significantly lower than flexed 30° (3.37 cm/s), flexed 15° (3.27 cm/s), and extended 30° (3.29 cm/s). Similarly, median nerve blood flow velocity was lower without force (2.81 cm/s) than with force (3.56 cm/s). A significant difference was not found between groups. Discussion. Vascular changes associated with CTS may be acutely induced by nonneutral wrist postures and fingertip force. This study represents an early evaluation of intraneural blood flow as a measure of nerve hypervascularization in response to occupational risk factors and advances our understanding of the vascular phenomena associated with peripheral nerve compression.

scholarly journals Nitric oxide is not obligatory for radial artery flow-mediated dilation following release of 5 or 10 min distal occlusion

2010 ◽  
Vol 298 (1) ◽  
pp. H119-H126 ◽  
Author(s):  
Kyra Pyke ◽  
Daniel J. Green ◽  
Cara Weisbrod ◽  
Matthew Best ◽  
Lawrence Dembo ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Shear Rate ◽  
Flow Velocity ◽  
Radial Artery ◽  
Blood Flow Velocity ◽  
Reactive Hyperemia ◽  
Area Under The Curve ◽  
Flow Mediated Dilation ◽  
Significant Difference

This study investigated the nitric oxide (NO) dependence of radial artery (RA) flow-mediated dilation (FMD) in response to three different reactive hyperemia (RH) shear stimulus profiles. Ten healthy males underwent the following three RH trials: 1) 5 min occlusion (5 trial), 2) 10 min occlusion (10 trial), and 3) 10 min occlusion with cuff reinflation at 30 s (10–30 trial). Trials were performed during saline infusion and repeated during NG-monomethyl-l-arginine (l-NMMA) infusion in the brachial artery. RA blood flow velocity was measured with Doppler ultrasound, and B-mode RA images were analyzed using automated edge detection software. Shear rate estimation of shear stress was calculated as the blood flow velocity/vessel diameter. l-NMMA decreased baseline vascular conductance by 35%. l-NMMA infusion did not affect the peak shear rate stimulus ( P = 0.681) or the area under the curve (AUC) of shear rate to peak FMD ( P = 0.088). The AUC was significantly larger in the 10 trial vs. the 10–30 or 5 trial ( P < 0.001). Although percent FMD (%change in diameter) in the 10 trial was larger than that in the 5 trial ( P = 0.035), there was no significant difference in %FMD between the saline and l-NMMA conditions in any trial: 5 trial, 5.62 ± 1.48 vs. 5.63 ± 1.27%; 10 trial, 9.07 ± 1.16 vs. 11.22 ± 2.21%; 10–30 trial, 6.52 ± 1.43 vs. 7.98 ± 1.51% for saline and l-NMMA, respectively ( P = 0.158). We conclude the following: 1) RH following 10 min of occlusion results in an enhanced stimulus and %FMD compared with 5 min of occlusion. 2) When the occlusion cuff is reinflated 30 s postrelease of a 10 min occlusion, it does not result in an enhanced %FMD compared with that which results from RH following 5 min of occlusion. 3) The lack of effect of l-NMMA on FMD suggests that NO may not be obligatory for radial artery FMD in response to either 5 or 10 min of occlusion in healthy volunteers.

Effect of body position and graduated compression stocking length on femoral venous blood flow velocity

2003 ◽  
Vol 18 (4) ◽  
pp. 198-202
Author(s):  
A Limpus ◽  
W P Chaboyer ◽  
C Purcell ◽  
P J Schluter ◽  
H Gibbs ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Body Position ◽  
Venous Blood ◽  
Vessel Diameter ◽  
Compression Stocking ◽  
Venous Blood Flow ◽  
Significant Difference ◽  
Three Body

Objectives: To measure the effect of graduated compression stocking (GCS) length and body position on peak femoral venous blood flow velocity (PVV) and vessel diameter (VD). Methods: Twenty healthy adult volunteers had PVV and VD measured, using colour Doppler ultrasound, at baseline in three body positions. Knee- or thigh-length GCS were assigned randomly.Arandom sequence of the three positions was used to measure PVV and VD. The procedure was repeated, after a two-hour washout period, using the other length GCS. Results: There was no significant difference in the mean change of PVV ( P =0.74) or VD ( P =0.54) measurements from the baseline between thigh- and knee-length GCS. However, significant mean changes in PVV ( P =0.02) and VD ( P <0.001) measurements were observed for the three body positions, after adjusting for baseline values. Conclusions: In healthy volunteers, thigh- and knee-length GCS do not have an effect on PVV or VD, and body position affects PVV significantly, with or without GCS.

scholarly journals Random squat/stand maneuvers: a novel approach for assessment of dynamic cerebral autoregulation?

2017 ◽  
Vol 123 (3) ◽  
pp. 558-566 ◽  
Author(s):  
Sam C. Barnes ◽  
Naomi Ball ◽  
Ronney B. Panerai ◽  
Thompson G. Robinson ◽  
Victoria J. Haunton
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Autoregulation ◽  
Arterial Blood ◽  
Transfer Function Analysis ◽  
Significant Difference ◽  
Random Frequency ◽  
Dynamic Cerebral Autoregulation

Squat/stand maneuvers (SSM) have been used to assess dynamic cerebral autoregulation (dCA), but always at a fixed frequency (FF). This study aimed to assess the use of random-frequency (RF) SSMs as a stimulus for measuring dCA and determine the reproducibility of FF and RFSSMs. Twenty-nine healthy volunteers [19 male, mean age 23.0 (4.9) yr] completed the study; 11 returned for a repeat visit (median 45 days). Heart rate, beat-to-beat blood pressure, middle cerebral artery (MCA) blood flow velocity, end-tidal CO2, and angle of the squat movement were measured. Subjects underwent four recordings: 5 min sitting, 5 min standing, FFSSMs (0.05Hz), and RFSSMs. Subjects were asked to rate the degree of exertion experienced while performing these maneuvers. Twenty-nine subjects completed the protocol; nine data sets were deemed unsuitable for further analysis. Mean ARI of 6.21 (1.04) while standing was significantly greater than during the SSMs ( P < 0.01), with mean (SD) ARI during the FF and RFSSMs being 5.16 (1.43) and 5.37 (1.21), respectively. However, no significant difference was found between the ARI estimates from the two SSMs ( P = 0.856) or for each of the four recordings between the two visits ( P = 0.645). RFSSMs were found to be significantly less tiring than FFSSMs ( P < 0.01). In conclusion, RFSSMs are an effective and noninvasive method of assessing dCA. There is no difference in the ARI estimates in comparison with FFSSMs. Although FFSSMs have been well tolerated previously, RFSSMs are preferred by healthy subjects and thus may be better tolerated by a patient population in a clinical setting. NEW & NOTEWORTHY RFSSMs provided comparable estimates of autoregulatory indices to FFSSMs. Instead of point estimates at the driven frequency, RFSSMs generate a broader power spectrum of changes in arterial blood pressure and cerebral blood flow velocity, allowing direct comparison with spontaneous fluctuations through transfer function analysis. Moreover, random-frequency SSMs are preferred by participants. They are a novel tool by which larger blood pressure oscillations can be elicited for the reliable measurement of dynamic cerebral autoregulation.

HEMODYNAMIC DISORDERS IN VARICOSE VEIN DISEASE

2021 ◽  
Vol 9 (1) ◽  
pp. 68-76
Author(s):  
R.E. Kalinin ◽  
◽  
I.A. Suchkov ◽  
I.N. Shanaev ◽  
V.A. Yudin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Varicose Vein ◽  
Blood Flow Velocity ◽  
Peripheral Resistance ◽  
Resistance Index ◽  
Significant Difference ◽  
Retrograde Blood Flow ◽  
Varicose Disease ◽  
Vein Disease

Aim. Duplex ultrasound scanning (DUS) is a routine diagnostic procedure in patients with varicose vein disease. DUS mostly evaluates the qualitative (anatomical) parameters of the disease. Still, it is difficult to assess the microcirculatory parameters in trophic disorders based only on the anatomy, therefore assessment of quantitative blood flow parameters is needed. Our aim was to determine the potentials of conventional DUS in assessment of the hemodynamic disorders in patients with varicose disease. Materials and Methods. The study included 583 patients with varicose disease, 348 of which had trophic alterations. The patients were divided into 4 groups according to the CEAP clinical classes. Standard Valsalva and Siegel tests were performed during DUS. The following parameters were assessed in the superficial and deep veins: diameter of veins, antegrade blood flow velocity, retrograde blood flow velocity, reflux time; in the perforator veins (PV) – diameter, maximum velocity and average velocity of reflux. Peripheral resistance index (RI) in the arteries accompanying the PV was also analyzed. Results. A statistically significant difference in the diameter of the GSV was obtained between classes C2 and C3, C3 and C4, but not between class C5, 6 and class C4. Similar findings were observed in the assessment of diameter of the PVs and the velocity of retrograde blood flow through them. A gradual increase in these parameters could be seen with the progression of the disease, but a statistically significant difference was obtained only between classes C2 and C3 for the diameter of the PV and the peak velocity of retrograde blood flow. As for the average blood flow velocity, a statistically significant difference was obtained between classes C2 and C3, C3 and C4. Arteries in the perforator bundles demonstrated low RI which may be attributed to the presence of an arteriolo-venular bypass. Statistically significant differences were obtained for CEAP classes C2 and C3. Conclusions. Ultrasound duplex scanning of the study with use of Superb Micro-Vascular Imaging mode is an effective method in assessing the quantitative and microcirculatory parameters of hemodynamic disorders in patients with varicose vein disease of the lower extremities. Trophic ulcers in varicose vein disease are not an obligatory component of the disease, but only its complication.

The relationship between blood pressure and sciatic nerve blood flow velocity in rats with insulin-treated experimental diabetes

2014 ◽  
Vol 11 (4) ◽  
pp. 281-289 ◽  
Author(s):  
T Dylan Olver ◽  
Kenneth N Grisé ◽  
Matthew W McDonald ◽  
Adwitia Dey ◽  
Matti D Allen ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Sciatic Nerve ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Experimental Diabetes ◽  
Nerve Blood Flow ◽  
The Relationship
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