Characteristics of reactive hyperemia in the cerebral circulation

1984 ◽  
Vol 246 (1) ◽  
pp. H52-H58 ◽  
Author(s):  
J. K. Gourley ◽  
D. D. Heistad
Keyword(s):  
Blood Flow ◽  
White Matter ◽  
Cerebral Ischemia ◽  
Gray Matter ◽  
Cerebral Circulation ◽  
Time Course ◽  
Reactive Hyperemia ◽  
Arterial Occlusion ◽  
Maximal Peak ◽  
Minimal Resistance

Reactive hyperemia has been characterized in many vascular beds, but little is known about quantitative characteristics of reactive hyperemia in the cerebral circulation. We measured velocity of blood flow and pial artery diameter to characterize the time course of reactive hyperemia and used microspheres to study regional blood flow in the brain. Cerebral ischemia was produced by raising intracranial pressure or by arterial occlusion with a cuff around the neck. Five seconds of ischemia produced virtually maximal peak reactive hyperemia, and 30 s of ischemia produced maximal peak reactive hyperemia. During reactive hyperemia after 30 s of cerebral ischemia, there was a three- to fourfold increase in cerebral blood flow. The magnitude of reactive hyperemia was greater in gray matter than in white matter. Minimal resistance during reactive hyperemia, after ischemia produced by arterial occlusion, is similar to minimal resistance during seizures or hypercapnia, which suggests that reactive hyperemia produces maximal vasodilatation. Oxygen saturation of cerebral venous blood increased almost twofold during reactive hyperemia, which indicates that factors in addition to venous (and presumably tissue) oxygen are important determinants of reactive hyperemia. In summary, 1) we have characterized the time course of reactive hyperemia in the cerebral circulation; 2) reactive hyperemia after arterial occlusion produces maximal cerebral vasodilatation; and 3) there is marked heterogeneity of the response, with much larger increases in flow in cortical gray matter than white matter.

Oxygen consumption in skeletal muscle during reactive hyperemia

1959 ◽  
Vol 197 (1) ◽  
pp. 190-192 ◽  
Author(s):  
Lloyd R. Yonce ◽  
W. F. Hamilton
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Time Course ◽  
Reactive Hyperemia ◽  
Control Level ◽  
Arterial Occlusion ◽  
Gracilis Muscle ◽  
Oxygen Deficit ◽  
Oxygen Difference ◽  
Increased Blood Flow

The surgical technique of isolation of the blood supply of the gracilis muscle of the dog has been developed for analysis of the oxygen consumption during reactive hyperemia. The time course of the blood flow, A-V oxygen difference and the oxygen consumption follow the same pattern. Immediately after the release of the arterial occlusion, there is an increase in all three values which decay and go below the control level that existed just prior to the occlusion. The increased oxygen consumption during reactive hyperemia is possible primarily by the increased blood flow, although the A-V oxygen difference is increased also. A theoretical oxygen deficit is overpaid by the oxygen consumption during the period of increased blood flow but essentially repaid if the period of decreased blood flow is included.

Peak calf blood flow estimates are higher with Dohn than with Whitney plethysmograph

1996 ◽  
Vol 81 (3) ◽  
pp. 1418-1422 ◽  
Author(s):  
D. N. Proctor ◽  
J. R. Halliwill ◽  
P. H. Shen ◽  
N. E. Vlahakis ◽  
M. J. Joyner
Keyword(s):  
Blood Flow ◽  
Reactive Hyperemia ◽  
Arterial Occlusion ◽  
Venous Occlusion ◽  
Calf Blood Flow ◽  
Absolute Flow ◽  
Wide Range ◽  
Before And After ◽  
The Mean ◽  
Highly Correlated

Estimates of calf blood flow with venous occlusion plethysmography vary widely between studies, perhaps due to the use of different plethysmographs. Consequently, we compared calf blood flow estimates at rest and during reactive hyperemia in eight healthy subjects (four men and four women) with two commonly used plethysmographs: the mercury-in-silastic (Whitney) strain gauge and Dohn air-filled cuff. To minimize technical variability, flow estimates were compared with a Whitney gauge and a Dohn cuff on opposite calves before and after 10 min of bilateral femoral arterial occlusion. To account for any differences between limbs, a second trial was conducted in which the plethysmographs were switched. Resting flows did not differ between the plethysmographs (P = 0.096), but a trend toward lower values with the Whitney was apparent. Peak flows averaged 37% lower with the Whitney (27.8 +/- 2.8 ml.dl-1.min-1) than with the Dohn plethysmograph (44.4 +/- 2.8 ml.dl-1.min-1; P < 0.05). Peak flow expressed as a multiple above baseline was also lower with the Whitney (10-fold) than with the Dohn plethysmograph (14.5-fold; P = 0.02). Across all flows at rest and during reactive hyperemia, estimates were highly correlated between the plethysmographs in all subjects (r2 = 0.96-0.99). However, the mean slope for the Whitney-Dohn relationship was only 60 +/- 2%, indicating that over a wide range of flows the Whitney gauge estimate was 40% lower than that for the Dohn cuff. These results demonstrate that the same qualitative results can be obtained with either plethysmograph but that absolute flow values will generally be lower with Whitney gauges.

Nonhyperemic blood flow restoration and brain edema in experimental focal cerebral ischemia

1989 ◽  
Vol 70 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Toshihiko Kuroiwa ◽  
Makoto Shibutani ◽  
Riki Okeda
Keyword(s):  
Blood Flow ◽  
Cerebral Ischemia ◽  
Brain Edema ◽  
Focal Cerebral Ischemia ◽  
Reactive Hyperemia ◽  
Diffusion Method ◽  
Left Middle Cerebral Artery ◽  
Content Type ◽  
Bbb Opening ◽  
Fine Print

✓ The effect of suppression of postischemic reactive hyperemia on the blood-brain barrier (BBB) and ischemic brain edema after temporary focal cerebral ischemia was studied in cats under ketamine and alpha-chloralose anesthesia. Regional cerebral blood flow (rCBF) was measured by a thermal diffusion method and a hydrogen clearance method. The animals were separated into three groups. In Group A, the left middle cerebral artery (MCA) was occluded for 6 hours. In Group B, the MCA was occluded for 3 hours and then reperfused for 3 hours; postischemic hyperemia was suppressed to the preischemic level by regulating the degree of MCA constriction. In Group C, the MCA was occluded for 3 hours and reperfused for 3 hours without suppressing the postischemic reactive hyperemia. The brain was removed and cut coronally at the site of rCBF measurement. The degree of ischemic edema was assessed by gravimetry in samples taken from the coronal section and correlated with the degree of BBB disruption at the corresponding sites, evaluated by densitometric determination of Evans blue discoloration. The findings showed that 1) ischemic edema was significantly exacerbated by postischemic hyperemia during reperfusion in parallel with the degree of BBB opening to serum proteins, and 2) suppression of postischemic hyperemia significantly reduced the exacerbation of ischemic edema and BBB opening. These findings indicate that blood flow may be restored without significant exacerbation of postischemic edema by the suppression of postischemic hyperemia in focal cerebral ischemia.

scholarly journals Time course of forearm arterial compliance changes during reactive hyperemia

2001 ◽  
Vol 281 (3) ◽  
pp. H1093-H1103 ◽  
Author(s):  
Damiano Baldassarre ◽  
Mauro Amato ◽  
Carlo Palombo ◽  
Carmela Morizzo ◽  
Linda Pustina ◽  
...  
Keyword(s):  
Time Course ◽  
Arterial Compliance ◽  
Reactive Hyperemia ◽  
Low Density Lipoprotein ◽  
Arterial Occlusion ◽  
Density Lipoprotein ◽  
Peak Time ◽  
Continuous Measurements ◽  
Measurement Protocol ◽  
Plasma High Density

Ultrasonic studies have shown that arterial compliance increases after prolonged ischemia. The objective of the present study was to develop an alternative plethysmographic method to investigate compliance, exploring validity and clinical applicability. Forearm pulse volume (FPV) and blood pressure (BP) were used to establish the FPV-BP relationship. Forearm arterial compliance (FAC) was measured, and the area under the FAC-BP curve (FACAUC) was determined. The time course curve of compliance changes during reactive hyperemia was obtained by continuous measurements of FACAUCfor 20 s before and for 300 s after arterial occlusion. This technique allows us to effectively assess compliance changes during reactive hyperemia. Furthermore, the selected measurement protocol indicated the necessity for continuous measurements to detect “true” maximal FACAUCchanges. On multivariate analysis, preischemic FACAUCwas mainly affected by sex, peak FACAUCwas affected by sex and systolic BP, percent changes were affected by plasma high-density and low-density lipoprotein cholesterol, peak time was affected by age and body mass index, and descent time was affected by plasma triglyceride levels. The proposed technique is highly sensitive and well comparable with the generally accepted echotracking system. It may thus be considered as an alternative tool to detect and monitor compliance changes induced by arterial occlusion.

Differences in reactive hyperemia between the intestinal mucosa and muscularis

1984 ◽  
Vol 247 (6) ◽  
pp. G617-G622
Author(s):  
A. P. Shepherd ◽  
G. L. Riedel
Keyword(s):  
Blood Flow ◽  
Metabolic Rate ◽  
Laser Doppler Velocimetry ◽  
Reactive Hyperemia ◽  
Arterial Occlusion ◽  
Oxygen Demand ◽  
Laser Doppler ◽  
Doppler Velocimetry ◽  
Total Blood ◽  
Total Blood Flow

In a previous study of regional intestinal blood flow by laser-Doppler velocimetry, we noted that the mucosa displayed reactive hyperemia following arterial occlusion but that the muscularis did not. Therefore, to determine whether this observation is generally valid, we compared responses of the mucosa and muscularis externa to arterial occlusion. We measured total blood flow to isolated loops of canine small bowel with an electromagnetic flow probe on the supply artery; blood flow either in the mucosa or in the muscularis was measured by laser-Doppler velocimetry. Mucosal and total blood flow consistently showed reactive hyperemia in response to a 60-s occlusion, but the muscularis did not. To determine whether metabolic rate influenced reactive hyperemia, we increased enteric oxygen uptake by placing 5% bile and transportable solutes in the lumen; these agents increased oxygen consumption by 36%. After a 60-s occlusion, the durations of both total and mucosal reactive hyperemia were significantly prolonged by increased metabolic rate. Similarly, the payback-to-debt ratios in both total and mucosal blood flows were significantly increased at elevated metabolic rate. These data support the conclusions that reactive hyperemia occurs more frequently and has a greater magnitude in the mucosa compared with the muscularis and both total and mucosal reactive hyperemia are strongly influenced by the preocclusive oxygen demand. These findings therefore constitute further evidence that metabolic factors contribute to reactive hyperemia in the intestinal circulation.

[14C]iodoantipyrine and microsphere blood flow estimates in cat brain

1987 ◽  
Vol 253 (5) ◽  
pp. H1289-H1297
Author(s):  
F. J. Schuier ◽  
S. C. Jones ◽  
T. Fedora ◽  
M. Reivich
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
White Matter ◽  
Spatial Resolution ◽  
Gray Matter ◽  
Local Cerebral Blood Flow ◽  
Normal Appearance ◽  
Diffusion Limited ◽  
Cat Brain ◽  
Temporal And Spatial

A comparison of local cerebral blood flow estimates with the microsphere and the 4-[N-methyl-14C]iodoantipyrine ([14C]IAP) techniques has been performed in cats. Good correlation of [14C]IAP with microsphere flow estimates in the gray matter was found. In the white matter, however, [14C]IAP flow estimates were consistently lower than microsphere flow estimates. Error analysis of both techniques and comparison with previous studies suggest that peculiarities of white matter arterial vasculature with preferential microsphere accumulation may lead to this discrepancy. Microspheres did not interfere with flow as shown by the normal appearance of subsequent [14C]IAP autoradiograms. The number of microspheres seen on autoradiograms was used for an estimate of microvessels blocked by spheres and found to be negligible. The study also demonstrates that [14C]IAP is not diffusion limited up to the observed flow values of 2 ml.g-1.min-1. Both techniques might be used together for a combination of their respective advantages, which are temporal and spatial resolution for microsphere and [14C]IAP, respectively.

Forearm Vasoreactivity in Type I Diabetic Subjects

2001 ◽  
Vol 26 (1) ◽  
pp. 34-43 ◽  
Author(s):  
Jason D. Allen ◽  
Michael Welsch ◽  
Nikki Aucoin ◽  
Robert Wood ◽  
Matt Lee ◽  
...  
Keyword(s):  
Risk Factors ◽  
Blood Flow ◽  
Vascular Function ◽  
Forearm Blood Flow ◽  
Reactive Hyperemia ◽  
Arterial Occlusion ◽  
Type I ◽  
Handgrip Exercise ◽  
Blood Flows

This study compared forearm vasoreactivity in 15 Type 1 diabetic subjects with 15 healthy controls. The groups were matched for age, exercise capacity, and the absence of other cardiovascular risk factors. Vasoreactivity was measured using strain gauge plethysmography, at rest, after arterial occlusion (OCC), and following OCC coupled with handgrip exercise (ROCC). Forearm blood flows were significantly elevated between conditions 2.58 ± 0.37 ml/100mltissue at rest to 26.80 ± 6.56 after OCC and 32.80 ± 8.26ml/100mltissue following ROCC in Type 1 diabetic subjects. There were no differences in forearm blood flow between groups for any of the conditions. These data indicate the degree of forearm blood flow is directly related to the intensity of the vasodilatory stimulus. However, our study did not reveal evidence of impaired vasodilatory capacity in Type 1 diabetic subjects compared to controls in the absence of other risk factors. Key words: IDDM, vascular function, exercise, fitness, and reactive hyperemia

Occlusion cuff position is an important determinant of the time course and magnitude of human brachial artery flow-mediated dilation

2000 ◽  
Vol 99 (4) ◽  
pp. 261-267 ◽  
Author(s):  
Karen L. BERRY ◽  
R. Andrew P. SKYRME-JONES ◽  
Ian T. MEREDITH
Keyword(s):  
Blood Flow ◽  
Brachial Artery ◽  
Time Course ◽  
Arterial Occlusion ◽  
Flow Mediated Dilation ◽  
Reactive Hyperaemia ◽  
Upper Arm ◽  
Brachial Artery Diameter ◽  
Occlusion Cuff ◽  
Forearm Occlusion

Non-invasive ultrasound techniques to assess flow-mediated vasodilation (FMD) are frequently used to assess arterial endothelial vasodilator function. However, the range of normal values varies considerably, possibly due to differences in methodological factors. We sought to determine the effect of occlusion cuff position on the time course and magnitude of brachial artery blood flow and flow-mediated dilation. Twelve healthy subjects underwent measurements of forearm blood flow using venous occlusion plethysmography (VOP) before and after 5 min of susprasystolic cuff inflation, using two randomly assigned occlusion cuff positions (upper arm and forearm). An additional 16 subjects underwent two brachial ultrasound studies, using the two cuff positions, to assess the extent and time course of changes in brachial artery diameter and blood flow. Maximum increase in blood flow (peak reactive hyperaemia), measured by VOP, occurred immediately upon each cuff deflation, but was greater after upper arm compared with forearm arterial occlusion (33.1±3.1 versus 22.8±2.2 ml/min per forearm tissue, P = 0.001). Maximal brachial artery FMD was significantly greater following upper arm occlusion (9.0±1.2%, mean±S.E.M.) compared with forearm occlusion (5.9±0.7%, P = 0.01). The time course of the change in brachial artery diameter was affected differently in response to each protocol. The time to peak dilation following upper arm occlusion was delayed by 22 s compared with forearm occlusion. Occlusion cuff position is thus a powerful determinant of peak reactive hyperaemia, volume repaid and the extent and time course of brachial artery FMD. Positioning the cuff on the upper arm produces a greater FMD. These results highlight the need for comparisons between FMD studies to be made with care.

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