Effect of rhythmically inflating a pneumatic cuff at the ankle on blood flow in the foot

1959 ◽  
Vol 14 (3) ◽  
pp. 411-413 ◽  
Author(s):  
R. Andrew Loane
Keyword(s):  
Blood Flow ◽  
Heat Flow ◽  
Perfusion Pressure ◽  
Venous Pressure ◽  
Venous Occlusion ◽  
Quantitative Agreement ◽  
Venous Occlusion Plethysmography ◽  
Flow Through ◽  
And Calorimetry

Rhythmic inflation to 110 mm Hg of a pneumatic cuff around the ankle of a seated subject reduces the venous pressure in the foot and is found by three methods, venous occlusion plethysmography, heat flow and calorimetry, to increase the rate of blood flow through the foot. The increases measured by the three methods are not, however, in quantitative agreement and it is not possible to decide how large the increase may be. It is considered, however, that the increase in flow is probably of the same order as the increase in perfusion pressure and not greatly in excess of this increase. Submitted on August 5, 1958

Intrinsic control of colonic blood flow and oxygenation

1980 ◽  
Vol 238 (6) ◽  
pp. G478-G484
Author(s):  
P. R. Kvietys ◽  
T. Miller ◽  
D. N. Granger
Keyword(s):  
Blood Flow ◽  
Vascular Resistance ◽  
Perfusion Pressure ◽  
Reactive Hyperemia ◽  
Venous Pressure ◽  
Arterial Occlusion ◽  
Venous Occlusion ◽  
Colonic Blood Flow ◽  
O2 Extraction ◽  
O2 Delivery

In a denervated autoperfused dog colon preparation, arterial perfusion pressure, venous outflow pressure, blood flow, and arteriovenous O2 difference were measured during graded arterial pressure alterations, arterial occlusion, venous pressure elevation, venous occlusion, and local intra-arterial infusion of adenosine. As perfusion pressure was reduced from 100 to 30 mmHg, colonic blood flow decreased and arteriovenous O2 difference increased. Although blood flow was not autoregulated O2 delivery was maintained within 10% of control between 70 to 100 mmHg and then decreased with further reduction in perfusion pressure. Arterial occlusion (15, 30, and 60 s) resulted in a postocclusion reactive hyperemia; the magnitude of the hyperemia was directly related to the duration of occlusion. Venous occlusion resulted in a postocclusion reactive hypoemia. Elevation of venous pressure from 0 to 20 mmHg increased vascular resistance, O2 extraction, and the capillary filtration coefficient, but decreased O2 delivery. Infusion of adenosine decreased vascular resistance and O2 extraction, but increased O2 delivery. These data suggest that both metabolic and myogenic mechanisms are involved in the control of colonic blood flow and oxygenation.

Maximal vasodilation does not eliminate the vascular waterfall in the canine hindlimb

1995 ◽  
Vol 79 (5) ◽  
pp. 1531-1539 ◽  
Author(s):  
I. Shrier ◽  
S. Magder
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Critical Pressure ◽  
Perfusion Pressure ◽  
Venous Pressure ◽  
Elastic Recoil ◽  
Recoil Pressure ◽  
Before And After ◽  
Flow Through ◽  
Stop Flow

Previous studies have shown that blood flow through skeletal muscle is regulated by changes in an arteriolar vascular waterfall [critical pressure (Pcrit)] and a proximal (arterial) resistance (Ra) element. To determine whether Pcrit still exists during maximal vasodilation, we pump perfused vascularly isolated canine hindlimbs. We set outflow pressure to zero and measured Pcrit, perfusion pressure (Pper), and regional elastic recoil pressure (Pcl; by a stop-flow technique) and calculated both Ra and venous resistance before and after maximal vasodilation with adenosine and nitroprusside. Pcrit was 56.4 +/- 5.1 mmHg before vasodilation and decreased to 11.0 +/- 0.6 mmHg after vasodilation, which was less than the downstream pressure in the venous compliant region (Pel). Therefore, Pcrit should not have affected flow at normal Pper levels under vasodilated conditions. However, we could still measure Pcrit because our technique allowed Pel to decline and Pcrit becomes apparent once Pel < Pcrit. With vasodilation, Ra decreased to < 8.1 +/- 2.6% and Rv decreased to 41 +/- 6% of control values. In contrast to the nonvasodilated vasculature, increases in venous pressure during maximal vasodilation caused immediate increases in Pper. This also suggests that the vascular waterfall is inactive under conditions of maximal vasodilation. We conclude that a small arteriolar Pcrit is still present in the maximally vasodilated hindlimb but is less than the downstream pressure and does not affect flow under these conditions.

scholarly journals Blood Perfusion of the Kidney of Lophius Piscatorius L.

1953 ◽  
Vol 32 (2) ◽  
pp. 329-336 ◽  
Author(s):  
L. Brull ◽  
E. Nizet ◽  
E. B. Verney
Keyword(s):  
Blood Flow ◽  
Critical Level ◽  
Perfusion Pressure ◽  
Blood Perfusion ◽  
Urine Flow ◽  
The Other ◽  
Protein Nitrogen ◽  
Other Hand ◽  
Flow Through

Lophius kidneys perfused with the heparinized blood (venous) of the fish secrete urine in which total non-protein nitrogen is concentrated, magnesium highly concentrated, and chloride only slightly so or not at all. Oxygenation of the blood, or lowering the temperature of the perfusate from c. 20° to c. 5° C. does not appear to influence secretion. The blood flow through the kidneys increases with the perfusion pressure, the increase often becoming disproportionately large. The urine flow, on the other hand, above a certain critical level is largely independent of changes in perfusion pressure.

Measurement of the cutaneous circulation

1965 ◽  
Vol 20 (4) ◽  
pp. 696-702 ◽  
Author(s):  
Harry M. Wright
Keyword(s):  
Blood Flow ◽  
Skin Temperature ◽  
Circulatory Arrest ◽  
Thermal Conductance ◽  
Venous Occlusion ◽  
Indirect Methods ◽  
Blood Content ◽  
Heating And Cooling ◽  
Flow Through ◽  
Cutaneous Circulation

Relationships between four commonly used indirect methods for study of the cutaneous circulation in intact, unanesthetized man were examined. Skin temperature, thermal conductance, volume plethysmography and the light absorption of the skin (as related to hemoglobin content) were simultaneously recorded on the upper extremities of normal young men as blood flow and blood content of the skin were changed by circulatory arrest, venous occlusion, indirect heating and cooling, and changes in position. Skin temperature and thermal conductance changed along parallel courses as blood flow was changed, while finger volume and reflectance of the skin to light of wavelength 550 mμ both changed in expected directions although along different courses, following passive congestion and de-congestion and changes in level of the hand relative to the heart. The advantages, disadvantages, and limitations of each of the methods in the study of cutaneous circulation in man are discussed and compared. measurement of circulation of skin; methods for measurement of cutaneous circulation; blood flow through skin; blood content of skin; skin Submitted on March 12, 1964

Blood flow elevation increases VO2 maximum during repetitive tetanic contractions of dog muscle in situ

1993 ◽  
Vol 74 (4) ◽  
pp. 1499-1503 ◽  
Author(s):  
W. F. Brechue ◽  
B. T. Ameredes ◽  
G. M. Andrew ◽  
W. N. Stainsby
Keyword(s):  
Blood Flow ◽  
Perfusion Pressure ◽  
Power Production ◽  
Arterial Supply ◽  
O2 Uptake ◽  
Plantaris Muscle ◽  
Control Series ◽  
Flow Through ◽  
Series Of Experiments

Blood flow through the gastrocnemius-plantaris muscle of the dog in situ was increased by a pump in the arterial supply during a 30-min period of 1/s isotonic tetanic contractions. Compared with a control series of experiments with normoxemia and spontaneous flow, the pump increased flow 84%, from 1.51 +/- 0.08 to 2.78 +/- 0.15 ml.g-1.min-1. The perfusion pressure was increased from 125 to 196 mmHg. The pump hyperemia increased maximal O2 uptake (VO2) at 5 min of contractions by 31%, from 8.97 +/- 0.44 to 12.89 +/- 0.30 mumol.g-1.min-1. The extraction was decreased, and venous PO2 (PVO2) was increased. Fatigue, measured as a drop in power production from the highest level at 10 s to 30 min, was 49% during pump hyperemia and 54% in the control conditions. VO2 decreased 30% from the 5-min value to the 30-min value with pump hyperemia and 28% over the same time in the control conditions. At maximal VO2, the ratio VO2/PVO2 was increased by pump hyperemia compared with control conditions, suggesting an increased O2 diffusing conductance of the muscles. We conclude that the elevated perfusion pressure of pump hyperemia increased flow to raise maximal VO2 mainly in areas of the muscle that had restricted flow under control conditions.

scholarly journals Cerebral Blood Flow in Patients with Intracranial Pressure Elevation due to Traumatic Brain Edema

1976 ◽  
Vol 3 (1) ◽  
pp. 35-37 ◽  
Author(s):  
W. A. Tweed ◽  
Jørn Overgaard
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Intracranial Pressure ◽  
Brain Edema ◽  
Cerebral Perfusion ◽  
Perfusion Pressure ◽  
Monitoring And Control ◽  
Intracranial Pressure Elevation ◽  
Flow Through ◽  
And Control

SUMMARY:The object of this study was to determine if traumatic brain edema (BE) and increased intracranial pressure (ICP) reduce cerebral blood flow (CBF). Two groups of patients were studied, one with slight BE and ICP less than 20 mm Hg., the other with pronounced BE and ICP over 20 mm Hg. Although ICP was higher and cerebral perfusion pressure lower in pro-nounced edema there was only a small and non-significant reduction in CBF and no difference in cerebro-vascular resistance. Since traumatic BE does not increase resistance to blood flow through the brain, cerebral perfusion can be maintained if an adequate perfusion pressure is established. This in turn, demands the monitoring and control of ICP.

THE EFFECT OF LOCAL TEMPERATURE ON INDIRECT VASODILATATION IN THE FEET

1967 ◽  
Vol 45 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Peter Gaskell ◽  
Garth M. Bray
Keyword(s):  
Blood Flow ◽  
Venous Occlusion ◽  
Venous Occlusion Plethysmography ◽  
Local Temperature ◽  
Cool Water ◽  
Arterial Blood

Lewis and Pickering reported in 1933 that warming occurred later in cool than in warm fingers in response to body heating. Factors which may be responsible were investigated. Measurement of rate of blood flow in the feet by venous occlusion plethysmography during body heating showed that vasodilatation in the feet occurred at the same time in a cool foot (18 to 23 °C) as in a warm (30 to 35 °C) but that warming of the cooler foot might be delayed for some time until the increase in flow was 0.5 ml/100 ml of foot per minute or more. In control experiments, with both feet in cool water or both in warm, the increase in blood flow during body heating started at the same time in both feet. Warming also began at the same time in both feet, but in the cool control experiments, warming often began later than did increase in flow. It is suggested that precooling of arterial blood may account for the delay in warming when the extremity is initially cool and the increase in blood flow is at first small during indirect vasodilatation.

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