A comparison of xenon-133 clearance with electromagnetic flowmeters and an indicator dilution method for the measurement of liver blood flow

Object Moderate hypothermia has been reported to be effective in the treatment of postischemic brain edema. The effect of hypothermia on cerebral hemodynamics is a matter of controversial discussion in literature. Clinical studies have yet to be performed in patients with ischemic stroke after induction of hypothermia. Methods Measurements during mild hypothermia (33–34°C) were made in six patients with severe ischemic stroke involving the middle cerebral artery territory. Hypothermia was induced as soon as possible and maintained for 48 to 72 hours. Cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were estimated by a new double-indicator dilution method. Measurements of CBF were made during normothermia, immediately after induction of hypothermia, at the end of hypothermia, and after rewarming. A total of 19 measurements of CBF and jugular bulb O2 saturation were made. Immediately after induction of hypothermia, CBF decreased in all patients. During late hypothermia, CBF improved in patients who survived but remained diminished in the two patients who died. Reduced CMRO2 levels were observed during all phases of hypothermia in all but one case. Conclusions Preliminary oberservations indicate that moderate hypothermia seems to reduce CMRO2 Immediately after induction of hypothermia, CBF may decrease in all patients. During late hypothermia CBF seems to recover in patients with good outcome but remains diminished in patients who die. Serial bedside CBF measurements with the new double-indicator dilution technique may be useful to describe cerebral hemodynamic characteristics in patients with severe ischemic stroke during hypothermia.

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Determination of Leg Blood Flow During Exercise in Man: An Indicator-Dilution Technique Based on Femoral Venous Dye Infusion

Clinical Science ◽

10.1042/cs0450135 ◽

1973 ◽

Vol 45 (2) ◽

pp. 135-146 ◽

Cited By ~ 5

Author(s):

J. Wahren ◽

L. Jorfeldt

Keyword(s):

Blood Flow ◽

Healthy Subjects ◽

Femoral Vein ◽

Indicator Dilution ◽

Dilution Method ◽

Dilution Technique ◽

Flow Measurements ◽

Leg Blood Flow ◽

Indicator Dilution Technique

1. A dye-dilution method has been developed for the determination of leg blood flow in man. The method is based on the infusion of indicator into the distal part of the femoral vein with blood sampling from the same vein at the level of the inguinal ligament. Catheterization of the femoral artery is not required. Evidence of adequate mixing of dye and blood is presented, based on the finding of the same dye concentration in samples from two different levels in the femoral vein. 2. Leg blood flow measured by this technique at rest and during exercise in six healthy subjects was found to agree closely with simultaneous determinations with an intra-arterial indicator-dilution technique. The reproducibility of the blood-flow measurements, expressed as the coefficient of variation for a single determination, was 9·8%. 3. A routine procedure is suggested for leg blood-flow determination based on femoral venous dye infusion. Using this procedure, leg blood flow was measured in twelve healthy subjects at rest and during exercise at work loads of 100, 200, 400 and 600 kpm/min. A linear relationship was found between leg blood flow and pulmonary oxygen uptake. 4. The applicability of this method to the study of patients with occlusive arterial disease of the leg is illustrated by findings in two patients before and after vascular reconstruction.

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On the Theory of the Indicator-Dilution Method for Measurement of Blood Flow and Volume

Journal of Applied Physiology ◽

10.1152/jappl.1954.6.12.731 ◽

1954 ◽

Vol 6 (12) ◽

pp. 731-744 ◽

Cited By ~ 917

Author(s):

Paul Meier ◽

Kenneth L. Zierler

Keyword(s):

Blood Flow ◽

Indicator Dilution ◽

Dilution Method

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Reflectometric Mapping of Microregional Blood Flow and Blood Volume in the Brain Cortex

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.1982.5 ◽

1982 ◽

Vol 2 (1) ◽

pp. 41-53 ◽

Cited By ~ 15

Author(s):

Andras Eke

Keyword(s):

Blood Flow ◽

Blood Volume ◽

Brain Cortex ◽

Mean Transit Time ◽

Minute Volume ◽

Indicator Dilution ◽

Dilution Method ◽

Computer Controlled ◽

Square Array ◽

The Brain

A reflectometric indicator-dilution method has been developed for mapping the parenchymal minute volume flow and blood content over tiny superficial areas of the brain cortex at 625 or 2500 locations, respectively. About 0.4 ml dextran-saline solution was used as nondiffusible indicator and injected into the feline cerebral circulation for each measurement. The subsequent cerebrocortical transit of the hemodiluted bolus was detected as a temporary change in the tissue optical density [OD( t)] and interpreted as indicator dilution, C( t). This gave the data necessary to calculate the microregional blood volume (mrCBV), mean transit time of the bolus (mrMTT), and the microregional blood flow (mrCBF = mrCBV/mrMTT). A two-dimensional record of the OD( t) function was made on Kodak SO 115 film by 16-mm cinematography, as a reflectometric tool, over an exposed area of the brain cortex during the bolus perfusion. Later, the microregional OD( t) functions were retrieved for analysis in a square array from the developed film by computer-controlled, frame-by-frame scanning densitometry. Maps of mrCBF, mrCBV, and mrMTT were presented as square arrays of gray-scaled pixels. The maximal spatial and temporal resolution of the method was 0.015 mm2 (mrCBF), 0.004 mm2 (mrCBV), 6 maps/min (mrCBF), and 600 maps/min (mrCBV).

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Effect of vasopressin on production of cerebrospinal fluid: possible role of vasopressin (V1)-receptors

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1990.258.1.r94 ◽

1990 ◽

Vol 258 (1) ◽

pp. R94-R98 ◽

Cited By ~ 6

Author(s):

F. M. Faraci ◽

W. G. Mayhan ◽

D. D. Heistad

Keyword(s):

Blood Flow ◽

Cerebrospinal Fluid ◽

Choroid Plexus ◽

Arginine Vasopressin ◽

Indicator Dilution ◽

Dilution Method ◽

Ventriculocisternal Perfusion ◽

Csf Production ◽

Humoral Regulation

The goal of this study was to examine the role of arginine vasopressin in humoral regulation of choroid plexus function. Production of cerebrospinal fluid (CSF) was measured in anesthetized rabbits with an indicator dilution method, by using ventriculocisternal perfusion of artificial CSF containing blue dextran. Rabbits received either vehicle, vasopressin or vasopressin in the presence of the V1-antagonist [1-(beta-mercapto-beta,beta-cyclopentamethylene propionic acid), 2-(O-methyl)tyrosine]arginine vasopressin ([d(CH2)5Tyr(Me)]-AVP). Under control conditions, blood flow to the choroid plexus (measured with microspheres) averaged 369 +/- 26 (mean +/- SE) ml.min-1.100 g-1 and CSF production averaged 9.9 +/- 0.9 microliters/min. Intravenous infusion of vasopressin (2 mU.kg-1.min-1 for 90 min) decreased blood flow to the choroid plexus by 50-60% for the entire period of infusion. Vasopressin decreased production of CSF by 35 +/- 8%. Blood flow to the choroid plexus and production of CSF did not change significantly from control values in animals that received vehicle. In the presence of the V1-antagonist (10 micrograms/kg), infusion of vasopressin had no effect on blood flow to the choroid plexus or production of CSF. Thus circulating vasopressin, at plasma levels that are observed under physiological and pathophysiological conditions, has important effects on formation of CSF, as well as on blood flow to the choroid plexus. These findings are consistent with the hypothesis that effects of vasopressin on both variables are mediated through vasopressin (V1)-receptors.

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The clearance of Xenon-133 following its parenchymal injection: a rapid method for estimating functional liver blood-flow

Clinical Physiology ◽

10.1111/j.1475-097x.1985.tb00774.x ◽

1985 ◽

Vol 5 (5) ◽

pp. 433-442 ◽

Cited By ~ 4

Author(s):

S. A. Jenkins ◽

A. Taylor ◽

S. K. Shimirty ◽

J. Johnson ◽

J. N. Baxter ◽

...

Keyword(s):

Blood Flow ◽

Rapid Method ◽

Liver Blood Flow ◽

Xenon 133

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Liver Blood Flow as a Major Determinant of the Clearance of Recombinant Human Tissue-Type Plasminogen Activator

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648385 ◽

1992 ◽

Vol 67 (01) ◽

pp. 083-087 ◽

Cited By ~ 44

Author(s):

A de Boer ◽

C Kluft ◽

J M Kroon ◽

F J Kasper ◽

H C Schoemaker ◽

...

Keyword(s):

Blood Flow ◽

Rat Liver ◽

Healthy Subjects ◽

Liver Blood Flow ◽

Major Determinant ◽

Tissue Type ◽

Perfused Rat Liver ◽

Liver Model ◽

Type Plasminogen Activator ◽

Proportional Change

SummaryThe influence of changes in liver blood flow on the clearance of rt-PA was studied both in healthy subjects and in a perfused rat liver model. Liver blood flow in healthy subjects was documented indirectly by the clearance of indocyanine green (ICG). Exercise reduced liver blood flow on average by 57% with a 95% confidence interval (95% Cl) ranging from 51% to 62% (n = 5) and increased plasma levels of rt-PA activity (after an i. v. infusion of 18 mg of rt-PA over 120 min) by 119% (95% Cl, 58% - 203%) and rt-PA antigen by 91% (95% Cl, 30% - 140%). In the perfused rat liver model it was shown that halving or doubling of the physiological flow rate of a perfusate, containing rt-PA caused a proportional change in the clearance of rt-PA, while the extraction of rt-PA by the liver remained similar. In conclusion, liver blood flow is a major determinant of the clearance of rt-PA. This may have important implications for dosage of rt-PA in patients with myocardial infarction.

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