Transmural Distributions of Blood Flow, Oxygen Tension, and Metabolism in Myocardium: Mechanism and Adaptations1

2015 ◽  
pp. 31-52 ◽  
Author(s):  
C. R. Honig ◽  
E. S. Kirk ◽  
W. W. Myers
Keyword(s):  
Blood Flow ◽  
Oxygen Tension

Local blood flow, oxygen tension, and oxygen consumption in the rat spinal cord

1983 ◽  
Vol 58 (4) ◽  
pp. 526-530 ◽  
Author(s):  
Nariyuki Hayashi ◽  
Barth A. Green ◽  
Mayra Gonzalez-Carvajal ◽  
Joseph Mora ◽  
Richard P. Veraa
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Oxygen Tension ◽  
Tissue Oxygen ◽  
Local Blood Flow ◽  
Rat Spinal Cord ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Tissue Oxygen Consumption

✓ Using a reliable and reproducible microelectrode technique, consistent simultaneous measurements of local spinal cord blood flow (SCBF), tissue oxygen tension, and tissue oxygen consumption were made at cervical, thoracic, and lumbar levels in the rat spinal cord. These observations showed that the metabolic state is maintained constant along the cord, despite significant variations in vasculature. The physiological and anatomical aspects of these findings are discussed.

Blood flow, blood oxygen tension, oxygen uptake, and oxygen transport in skeletal muscle

1964 ◽  
Vol 206 (4) ◽  
pp. 858-866 ◽  
Author(s):  
Wendell N. Stainsby ◽  
Arthur B. Otis
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Oxygen Tension ◽  
Capillary Density ◽  
Muscle Group ◽  
Blood Oxygen ◽  
Histological Techniques ◽  
Contracting Muscle ◽  
Resting Muscle

The effect of changes in blood flow and of blood oxygen tension on oxygen uptake of the in situ gastrocnemius-plantaris muscle group of the dog was examined. Oxygen uptake by resting muscle was not altered by changes in blood flow or blood oxygen tension except when these parameters were reduced below critical values. When the muscle group was contracting once per second, changes in blood oxygen tension were similarly without effect until a critically low value was reached. Although the contracting muscle used eight times as much oxygen per minute as resting muscle, the critical oxygen tension was lower than that for resting muscle. In an attempt to explain this observation the blood-tissue oxygen tension difference was estimated and used in the Krogh equation to calculate capillary density. The capillary density in contracting muscle was found to be much greater than in resting muscle and was about the same as the capillary density measured by others by histological techniques.

Hypoxic effect of exogenous insulin on normal and diabetic peripheral nerve

1994 ◽  
Vol 266 (6) ◽  
pp. E980-E985 ◽  
Author(s):  
M. Kihara ◽  
P. J. Zollman ◽  
I. L. Smithson ◽  
T. D. Lagerlund ◽  
P. A. Low
Keyword(s):  
Blood Flow ◽  
Peripheral Nerve ◽  
Oxygen Tension ◽  
Glycosylated Hemoglobin ◽  
Diabetic Rats ◽  
Insulin Administration ◽  
Dissociation Curve ◽  
Nerve Blood Flow ◽  
Intravenous Insulin ◽  
Arteriovenous Shunts

Insulin administration can cause or worsen experimental and human diabetic neuropathy ("insulin neuritis"). In this study, we tested the hypothesis that insulin administration impairs tissue oxygenation. We infused insulin under nonhypoglycemic conditions and evaluated its effect on endoneurial oxygen tension, nerve blood flow, and the oxyhemoglobin dissociation curve of peripheral nerve in normal and diabetic rats. Intravenous insulin infusion resulted in a dose-dependent reduction in endoneurial oxygen tension in normal nerves (from 26% at 0.04 U/kg insulin to 55% at 32 U/kg). The nerves of rats with streptozotocin-induced diabetes were resistant, but with control of hyperglycemia this susceptibility to the endoneurial hypoxic effect of insulin returned. The reduction in endoneurial oxygen tension regressed with glycosylated hemoglobin (Y = 53.8-2.7X, where Y = %reduction in endoneurial oxygen tension and X = HbA1; r = 0.87; P = < 0.001). Diabetes or insulin administration resulted in only minimal and physiologically insignificant alterations in the oxygen dissociation curve and 2,3-diphosphoglycerate of sciatic nerve. Instead, insulin administration resulted in a reduction in nerve nutritive blood flow and an increase in arteriovenous shunt flow. When the latter was eliminated by the closure of arteriovenous shunts (infusion of 5-hydroxytryptamine), endoneurial oxygen reverted to normal. These findings indicate a deleterious vasoactive effect of insulin and may explain the development of insulin neuritis.

Acute Normovolemic Hemodilution Improves Oxygenation in Ischemic Flap Tissue

2002 ◽  
Vol 96 (6) ◽  
pp. 1478-1484 ◽  
Author(s):  
Sören Schramm ◽  
Reto Wettstein ◽  
Robert Wessendorf ◽  
Stephan M. Jakob ◽  
Andrej Banic ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Tension ◽  
Base Excess ◽  
Hemoglobin Concentration ◽  
Linear Increase ◽  
Control Group ◽  
Total Blood ◽  
Normovolemic Hemodilution ◽  
Total Blood Flow ◽  
Ischemic Flap

Background The flaps used in reconstructive surgery are prone to ischemia and hypoxia, which imply a considerable risk of wound-healing complications. During normovolemic hemodilution, the oxygenation may further deteriorate because of the lack of erythrocytes or improve because of increased microcirculatory blood flow. The aim of this study was to investigate the net effect of normovolemic hemodilution of various degrees on the microcirculation and oxygenation in ischemic flap tissue in adult minipigs. Methods A rectangular flap was raised in the middle of the epigastrium, consisting of an adequately perfused portion and a partly ischemic portion. The animals were randomly assigned to either the control group (n = 10) or the experimental group (n = 10) receiving graded normovolemic hemodilution with 6% hydroxyethyl starch 200-0.5. Results Normovolemic hemodilution caused a significant linear increase in total blood flow to the flap (measured by transit time flowmetry). In the ischemic flap tissue, both oxygen tension (measured by polarographic cells) and venous base excess were transiently improved during hemodilution (F = 4.79 and P = 0.019 for the regression of tissue oxygen tension on hemoglobin and hemoglobin squared, and F = 4.18 and P = 0.029 for base excess). The expected values reached a peak at hemoglobin concentrations of 9.1 and 8.5 g/dl, respectively. The measured values at this level of hemodilution were 17 +/- 10.7 mmHg (mean +/- SD) versus 7.6 +/- 1.9 mmHg (baseline) for oxygen tension and -1.7 +/- 3.4 versus -5.6 +/- 4.1 mM for venous base excess. Conclusions Our results suggest that the oxygenation in ischemic and hypoxic flap tissue may be improved by normovolemic hemodilution. The maximal benefit may be expected at a hemoglobin concentration at or slightly less than 9 g/dl.

Correlation of Conjunctival Oxygen Tension with Carotid Artery Blood Flow During Hemorrhagic Hypotension

1988 ◽  
pp. 499-502
Author(s):  
Yoshinori Kikuta ◽  
Otowa Moritsune ◽  
Hiroaki Kawabata ◽  
Shinkichi Tezuka ◽  
Kazuo Okada ◽  
...  
Keyword(s):  
Blood Flow ◽  
Carotid Artery ◽  
Oxygen Tension ◽  
Artery Blood Flow ◽  
Hemorrhagic Hypotension ◽  
Conjunctival Oxygen Tension
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