Cerebral blood flow during static exercise in humans

Cerebral blood flow (CBF) was determined in humans at rest and during four consecutive unilateral static contractions of the knee extensors. Each contraction was maintained for 3 min 15 s with the subjects in a semisupine position. The contractions corresponded to 8, 16, 24, and 32% of the maximal voluntary contraction (MVC) and utilized alternate legs. CBF (measured by the 133Xe clearance technique) was expressed by a noncompartmental flow index (ISI). Heart rate and mean arterial pressure increased from resting values of 73 (55-80) beats/min and 88 (74-104) mmHg to 106 (86-138) beats/min and 124 (102-146) mmHg, respectively (P less than 0.0005), during the contraction at 32% MVC. Arterial PCO2 and central venous pressure did not change. Corrected to the average resting PCO2, CBF during control was 55 (35-73) ml.100 g-1.min-1 and remained constant during contractions. Cerebral vascular resistance increased from 1.5 (1.0-2.2) to 2.4 (1.4-3.0) mmHg. 100 g.min.ml-1 (P less than 0.025) at 32% of MVC. There was no difference in CBF between the two hemispheres at rest or during exercise. In contrast to dynamic leg exercise, static leg exercise is not associated with an increase in global CBF when measured by the 133Xe clearance technique.

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Measurement of cerebral blood flow in the pig by the 133Xe clearance technique

European Journal of Nuclear Medicine ◽

10.1007/bf00252804 ◽

1981 ◽

Vol 6 (10) ◽

pp. 461-468 ◽

Cited By ~ 1

Author(s):

A. C. W. Volkers ◽

W. A. van Duyl

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

133Xe Clearance ◽

Clearance Technique

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An Assessment of Dynamic Autoregulation from Spontaneous Fluctuations of Cerebral Blood Flow Velocity: A Comparison of Two Models, Index of Autoregulation and Mean Flow Index

Anesthesia & Analgesia ◽

10.1213/01.ane.0000295802.89962.13 ◽

2008 ◽

Vol 106 (1) ◽

pp. 234-239 ◽

Cited By ~ 45

Author(s):

Marek Czosnyka ◽

Piotr Smielewski ◽

Andrea Lavinio ◽

John D. Pickard ◽

Ronney Panerai

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Flow Velocity ◽

Blood Flow Velocity ◽

Cerebral Blood Flow Velocity ◽

Flow Index ◽

Mean Flow ◽

Spontaneous Fluctuations

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Blood Flow Assessment of Arteriovenous Malformations Using Intraoperative Indocyanine Green Videoangiography

Stroke Research and Treatment ◽

10.1155/2019/7292304 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Naoki Kato ◽

Vincent Prinz ◽

Julius Dengler ◽

Peter Vajkoczy

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Indocyanine Green ◽

Region Of Interest ◽

Flow Dynamics ◽

Flow Index ◽

Indocyanine Green Videoangiography ◽

Blood Flow Index ◽

High Resolution Images ◽

The Individual

Intraoperative indocyanine green (ICG) videoangiography is widely used in patients undergoing neurosurgery. FLOW800 is a recently developed analytical tool for ICG videoangiography to assess semi-quantitative flow dynamics; however, its efficacy is unknown. In this study, we evaluated its functionality in the assessment of flow dynamics of arteriovenous malformation (AVM) through ICG videoangiography under clinical settings. ICG videoangiography was performed in the exposed AVM in eight patients undergoing surgery. FLOW800 analysis was applied directly, and gray-scale and color-coded maps of the surgical field were obtained. After surgery, a region of interest was placed on the individual vessels to obtain time-intensity curves. Parameters of flow dynamics, including the maximum intensity, transit time, and cerebral blood flow index, were calculated using the curves. The color-coded maps provided high-resolution images; however, reconstruction of colored images was restricted by the depth, approach angle, and brain swelling. Semi-quantitative parameters were similar among the feeders, niduses, and drainers. However, a higher cerebral blood flow index was observed in the feeders of large AVM (>3 cm) than in those of small AVM (P < 0.05). Similarly, the cerebral blood flow index values were positively correlated with the nidus volume (P < 0.01). FLOW800 enabled visualization of the AVM structure and safer resection, except in case of deep-seated AVM. Moreover, semi-quantitative values in the individual vessels through using ICG intensity diagram showed different patterns according to size of the AVM. ICG videoangiography showed good performance in evaluating flow dynamics of the AVM in patients undergoing surgery.

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Effect of Pentoxifylline on Cerebral Blood Flow in Patients with Chronic Cerebrovascular Disease

Journal of International Medical Research ◽

10.1177/030006058100900311 ◽

1981 ◽

Vol 9 (3) ◽

pp. 211-214 ◽

Cited By ~ 5

Author(s):

Stefano Passero ◽

Marcello Nardini ◽

Noé Battistini

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Cerebrovascular Disease ◽

Pharmacological Treatment ◽

Intravenous Infusion ◽

Chronic Administration ◽

Before And After ◽

Clearance Technique

The effect of pentoxifylline on cerebral blood flow (CBF) was studied with the intravenous 133Xe clearance technique in eleven patients with chronic cerebrovascular disease. Pentoxifylline was administered orally at a dose of 1200 mg/day over a period of 30 days (eight patients) or by intravenous infusion of 100 ml saline containing 400 mg of the drug in 1 hour (three patients). CBF was measured before and after pharmacological treatment. CBF was found to be significantly increased by both acute and chronic administration of pentoxifylline.

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INFLUENCE OF VENOUS PRESSURE (VP) ON CEREBRAL BLOOD FLOW NEWBORN DOGS

Pediatric Research ◽

10.1203/00006450-198404001-00291 ◽

1984 ◽

Vol 18 ◽

pp. 141A-141A

Author(s):

Andrew J Mcphee ◽

Uma R Kotagal ◽

Leonard I Kleinman

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Venous Pressure

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Near-infrared estimation of O2 supply and consumption in forearm muscles working at varying intensity

Journal of Applied Physiology ◽

10.1152/jappl.1996.80.4.1279 ◽

1996 ◽

Vol 80 (4) ◽

pp. 1279-1284 ◽

Cited By ~ 74

Author(s):

S. Homma ◽

H. Eda ◽

S. Ogasawara ◽

A. Kagaya

Keyword(s):

Blood Flow ◽

Near Infrared ◽

Maximum Voluntary Contraction ◽

Venous Occlusion ◽

Voluntary Contraction ◽

Flow Index ◽

O2 Consumption ◽

Rate Of Increase ◽

Consumption Index ◽

O2 Supply

We estimated a blood flow index, O2 supply index, and O2 consumption index from near-infrared (NIR) signals during venous occlusion imposed at rest and immediately after handgrip exercise with loads equal to 5, 10, 15, 20, 25, and 30% of the maximum voluntary contraction. We also estimated forearm blood flow (BFfa) by strain-gauge plethysmography and forearm O2 consumption (VO2fa) by the invasive method. There was a significant correlation between the rate of increase in total hemoglobin during venous occlusion obtained from NIR signals and BFfa in each subject (r = 0.853 approximately 0.981, P < 0.001). There was also a significant correlation (r = 0.854 approximately 0.944, P < 0.001) between the O2 consumption index estimated from NIR signals and VO2fa. The mean values for O2 supply index in five subjects increased with exercise intensity, while the O2 consumption index showed no further increase about 25% of maximum voluntary contraction. We found significant positive correlations between the O2 supply index and BFfa (r = 0.986, P < 0.001) and the O2 consumption index and VO2fa (r = 0.976, P < 0.001) during exercise at 5-30% of maximum voluntary contraction. These results demonstrate that analysis of NIR signals during venous occlusion provides an advantageous method of estimation of O2 supply and consumption in working muscles during exercise of varying intensity.

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