scholarly journals Compensatory increases in cardiac output and SMA blood flows prevent splanchnic hypoperfusion during moderate isovolemic hemodilution in dogs

Critical Care ◽  
2001 ◽  
Vol 5 (S3) ◽  
Author(s):  
D Perin ◽  
RJ Cruz ◽  
LF Poli de Figueiredo ◽  
JOC Auler ◽  
M Rocha e Silva
Keyword(s):  
Cardiac Output ◽  
Isovolemic Hemodilution ◽  
Blood Flows ◽  
Splanchnic Hypoperfusion

Catecholamines and regional hemodynamics during isovolemic hemodilution in anesthetized pigs

1992 ◽  
Vol 72 (2) ◽  
pp. 760-769 ◽  
Author(s):  
E. C. Van Woerkens ◽  
A. Trouwborst ◽  
D. J. Duncker ◽  
M. M. Koning ◽  
F. Boomsma ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Left Ventricular ◽  
Oxygen Flux ◽  
Isovolemic Hemodilution ◽  
Blood Flows ◽  
Regional Hemodynamics ◽  
Regional Blood Flows ◽  
Total Body Oxygen

The effects of stepwise isovolemic hemodilution on systemic and regional hemodynamics, oxygen flux, and circulating catecholamines were studied in six pigs anesthetized with midazolam and fentanyl. Reduction of the hematocrit from 28 to 9% resulted in doubling of the cardiac output, mainly due to an increase in stroke volume. Regional blood flows, measured using the radioactive microsphere technique, showed an increase in blood flow to all organs except liver (hepatic artery fraction) and adrenals, with a redistribution of cardiac output in favor of heart and brain (increase in blood flow 420 and 170%, respectively). Oxygen flux to most organs did not decrease until hematocrit decreased to 9%, while total body oxygen consumption was well maintained. Left ventricular oxygen consumption increased, but because left ventricular blood flow also increased, left ventricular extraction ratio did not increase. Circulating catecholamines did not play any role in these regulatory mechanisms.

Costal vs. crural diaphragmatic blood flow during submaximal and near-maximal exercise in ponies

1988 ◽  
Vol 65 (4) ◽  
pp. 1514-1519 ◽  
Author(s):  
M. Manohar
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Left Atrium ◽  
Maximal Exercise ◽  
Muscle Blood Flow ◽  
Intercostal Muscle ◽  
Quiet Breathing ◽  
Blood Flows ◽  
Graded Exercise ◽  
Crural Diaphragm

The present study was carried out 1) to compare blood flow in the costal and crural regions of the equine diaphragm during quiet breathing at rest and during graded exercise and 2) to determine the fraction of cardiac output needed to perfuse the diaphragm during near-maximal exercise. By the use of radionuclide-labeled 15-micron-diam microspheres injected into the left atrium, diaphragmatic and intercostal muscle blood flow was studied in 10 healthy ponies at rest and during three levels of exercise (moderate: 12 mph, heavy: 15 mph, and near-maximal: 19-20 mph) performed on a treadmill. At rest, in eucapnic ponies, costal (13 +/- 3 ml.min-1.100 g-1) and crural (13 +/- 2 ml.min-1.100 g-1) phrenic blood flows were similar, but the costal diaphragm received a much larger percentage of cardiac output (0.51 +/- 0.12% vs. 0.15 +/- 0.03% for crural diaphragm). Intercostal muscle perfusion at rest was significantly less than in either phrenic region. Graded exercise resulted in significant progressive increments in perfusion to these tissues. Although during exercise, crural diaphragmatic blood flow was not different from intercostal muscle blood flow, these values remained significantly less (P less than 0.01) than in the costal diaphragm. At moderate, heavy, and near-maximal exercise, costal diaphragmatic blood flow (123 +/- 12, 190 +/- 12, and 245 +/- 18 ml.min-1.100 g-1) was 143%, 162%, and 162%, respectively, of that for the crural diaphragm (86 +/- 10, 117 +/- 8, and 151 +/- 14 ml.min-1.100 g-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous Airway Pressure Breathing With the Head-Box in the Newborn Lamb: Effects on Regional Blood Flows

PEDIATRICS ◽  
1977 ◽  
Vol 59 (6) ◽  
pp. 858-864
Author(s):  
G. Gabriele ◽  
C. R. Rosenfeld ◽  
D. E. Fixler ◽  
J. M. Wheeler
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Airway Pressure ◽  
Left Ventricular Pressure ◽  
Blood Gases ◽  
Ocular Blood Flow ◽  
Left Ventricular ◽  
Positive Pressure ◽  
Blood Flows ◽  
Arterial Blood

Continuous airway pressure delivered by a head-box is an accepted means of treating clinical hyaline membrane disease. To investigate hemodynamic alterations resulting from its use, eight newborn lambs, 1 to 6 days of age, were studied at 6 and 11 mm Hg of positive pressure, while spontaneously breathing room air. Organ blood flows and cardiac output were measured with 25 µ-diameter radioactive microspheres. Heart rate, left ventricular pressure, and arterial blood gases did not change during the study. Jugular venous pressures increased from 6.4 mm Hg to 18.6 and 24.2 mm Hg at 6 and 11 mm Hg, respectively (P < .005). Cardiac output decreased approximately 20% at either intrachamber pressure setting. Renal blood flow fell 21% at 11 mm Hg. No significant changes in blood flow were found in the brain, gastrointestinal tract, spleen, heart, or liver when compared to control flows. Of particular interest was the finding of a 28% reduction in ocular blood flow at 6 mm Hg and 52% at 11 mm Hg. From these results, we conclude that substantial cardiovascular alterations may occur during the application of head-box continuous airway pressure breathing, including a significant reduction in ocular blood flow.

Norepinephrine elevation in the fetal lamb: oxygen consumption and cardiac output

1980 ◽  
Vol 239 (1) ◽  
pp. R115-R122 ◽  
Author(s):  
R. H. Lorijn ◽  
L. D. Longo
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Diffusing Capacity ◽  
Blood Flows ◽  
Umbilical Blood ◽  
Arterial Blood ◽  
Fetal Lamb ◽  
O2 Diffusion ◽  
Umbilical Blood Flow ◽  
Higher Doses

In an effort to determine if placental diffusion reserves exceed fetal O2 requirements, we increased fetal O2 consumption (VO2) by infusing 1.7-11.5 microgram of norepinephrine (NE) . min-1. After 50 min of infusion VO2 rose 25% to 10.2 from 8.2 ml . min-1 . kg fetal wt-1. Placental CO diffusing capacity remained essentially unchanged from control, 0.49 +/- 0.05 (SE) ml . min-1. Torr-1 . kg-1, During the first 5 min of NE infusion fetal arterial blood pressure increased 29%, while heart rate decreased 15%. In addition, coronary, pulmonary, and umbilical blood flow, expressed per kilogram of fetal weight as determined by use of labeled microspheres, increased 50, 162, and 25%, respectively (P less than 0.05), although fetal cardiac output remained constant at 538 +/- 23 (SE) ml . min-1 . kg-1. Finally, we determined the NE-blood pressure dose-response relations for the fetus; Blood pressure increased with doses up to 1 microgram . min-1 . kg-1, but failed to rise further with higher doses. We conclude that 1) fetal VO2 increases with NE infusion 2) the placental reserve for O2 diffusion exceeds normal requirements, and 3) NE infusion is associated with increased blood pressure, bradycardia, and a redistribution of blood flows to the heart, lungs, and placenta despite a constant cardiac output.

Prevention of fatal hemorrhagic shock in dog by pretreatment with chronic high-salt diet

1985 ◽  
Vol 249 (3) ◽  
pp. H577-H584
Author(s):  
A. P. Rocchini ◽  
K. P. Gallagher ◽  
M. J. Botham ◽  
J. H. Lemmer ◽  
C. A. Szpunar ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Sodium Chloride ◽  
Hemorrhagic Shock ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Plasma Renin ◽  
High Salt ◽  
High Salt Diet ◽  
Salt Diet ◽  
Blood Flows

The ability of a chronic high-salt diet to prevent fatal hemorrhagic shock was examined in 36 mongrel dogs. Twenty-one dogs received a dietary supplement of 9 g sodium chloride/day for 6 wk, and 15 dogs received the same basic diet for 6 wk but without the sodium chloride supplement. Hemorrhagic shock was induced in all dogs by bleeding into an overhanging sealed reservoir. After 3 h of shock, salt-pretreated dogs had a lower systemic vascular resistance of 0.70 +/- 0.02 versus 1.44 +/- 0.04 mmHg X ml-1 X min X kg (P less than 0.01) and a higher cardiac output of 53 +/- 3 versus 26 +/- 3 ml X min-1 X kg-1 (P less than 0.01) than was observed in controls. At 2.5 h of shock, the salt-pretreated dogs also experienced an increase in gastrointestinal (P less than 0.01), hepatic arterial, (P less than 0.05), kidney (P less than 0.05), brain (P less than 0.01), and heart blood flows (P less than 0.001) compared with 0.5 h of shock, whereas the control dogs experienced no increased flow during this same period. We also observed that after 3 h of hypotension there was a significantly smaller increase in plasma renin activity in the salt-pretreated dogs. Administration of 0.1 U X kg-1 X min-1 of hog renin eliminated the differences in systemic vascular resistance, cardiac output, and survival in five salt-pretreated dogs.

Reference sample method for cardiac output and regional blood flow determinations in the rat

1976 ◽  
Vol 40 (3) ◽  
pp. 472-475 ◽  
Author(s):  
A. B. Malik ◽  
J. E. Kaplan ◽  
T. M. Saba
Keyword(s):  
Cardiac Output ◽  
Regional Blood Flow ◽  
Reference Sample ◽  
Peripheral Arteries ◽  
Blood Flows ◽  
Tissue Weight ◽  
Regional Blood Flows ◽  
Sample Method ◽  
The Brain ◽  
Cardiac Output Measurements

The reference sample method was used for simultaneous determinations of cardiac output and regional blood flows in conscious rats. Microspheres (15 +/- 5 mum in diam) labeled with strontium-85 were injected into the left ventricle and known volumes of reference sample were withdrawn from peripheral arteries. The calculated cardiac output measurements agreed with the previously reported values in rats. The percent distribution of the cardiac output to the brain, intestinal bed, and lungs were different from the reported values obtained in the rats using larger spheres. These differences may be related to the use of smaller spheres and to differences in the preparation. The absolute regional flows to various organs expressed in terms of milliliters per minute per gram tissue weight were also determined. The results indicate that the reference sample method can be applied to smaller mammals for determinations of regional flows and cardiac output.

Circulation of sympathectomized dogs under pentobarbital anesthesia

1965 ◽  
Vol 208 (4) ◽  
pp. 790-794
Author(s):  
Shu Chien ◽  
Shunichi Usami
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Blood Volume ◽  
Total Blood Volume ◽  
Central Blood Volume ◽  
Total Blood ◽  
Pentobarbital Anesthesia ◽  
Blood Flows ◽  
The Mean ◽  
Mean Circulation

In sympathectomized-splenectomized dogs under pentobarbital anesthesia, the total blood volume averaged 78 ml/kg, with 20% in the splanchnic circulation and 28% in the central blood volume. These values are almost the same as those found in the splenectomized (control) dogs with the sympathetic system intact. The over-all and the splanchnic Fcells factors are also not significantly different between these two groups. The sympathectomized animals had lower arterial pressure, cardiac output, and splanchnic blood flow, but the resistances calculated for the total and the splanchnic circulations were not significantly different from those of the control dogs. The mean circulation times for the total, the central, and the splanchnic circulations were all longer in the sympathectomized dogs. The data indicate that, under pentobarbital anesthesia, sympathectomized dogs are characterized by slower blood flows without any significant changes in either the blood volume or vascular resistance.

Responses of reproductive and nonreproductive tissues to 17 beta-estradiol during ovine puerperium

1980 ◽  
Vol 239 (5) ◽  
pp. E333-E339 ◽  
Author(s):  
C. R. Rosenfeld
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Mammary Gland ◽  
Thyroid Gland ◽  
Vascular Reactivity ◽  
Progressive Increase ◽  
Fallopian Tubes ◽  
Blood Flows ◽  
Flow Response ◽  
Regional Blood Flows

The responses of regional blood flows and cardiac output to the systemic infusion of 17 beta-estradiol (E2) (1 microgram/kg) were studied with radionuclide-labeled microspheres in 11 chronically instrumented ewes 1-12 days after lambing. Blood flow to the uterine myometrium, endometrium, and caruncles increased 818 +/- 212, 1,149 +/- 376, and 544 +/- 160% (mean +/- SE, P < 0.025), respectively, within 90 min after the infusion of E2. There was, however, in each of these tissues a progressive increase in the magnitude of the response to E2 stimulation as the puerperium progressed, not attaining changes expected in the prepregnant ewe until the 12th postpartum day. Significant vasodilation also occurred in the fallopian tubes, cervix, vagina, ovaries, mammary gland, skin, and thyroid gland. The magnitude of the blood flow response in the tubes, cervix, and vagina increased as the puerperium progressed. Cardiac output rose 17 +/- 10% (P < 0.05) after the infusion of E2. Although the ovine reproductive tissues are sensitive to estrogen-induced vasodilation throughout the puerperium, the magnitude of the responses progressively increase, suggesting that vascular reactivity in these tissues is changing and is not similar to that of the prepregnant animal.

Cardiac output distribution during vasopressin infusion or dehydration in conscious dogs

1982 ◽  
Vol 243 (5) ◽  
pp. H663-H669 ◽  
Author(s):  
J. F. Liard ◽  
O. Deriaz ◽  
P. Schelling ◽  
M. Thibonnier
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Output ◽  
Arginine Vasopressin ◽  
Muscle Blood Flow ◽  
Electromagnetic Flowmeter ◽  
Cardiovascular Effects ◽  
Water Restriction ◽  
Vascular Effects ◽  
Vasopressin Infusion ◽  
Blood Flows

To better understand the role of arginine vasopressin in cardiovascular regulation, we measured in unanesthetized dogs regional blood flows with radioactive microspheres before and during 1-h vasopressin infusions that increased the vasopressin concentration of plasma by 11 +/- 0.6 pg/ml. Cardiac output measured by an electromagnetic flowmeter decreased by 13%. Blood flows to the skeletal muscle and skin, the areas most affected, decreased by 30.8 and 34.3%, respectively. In the same group of dogs a period of 48-h water restriction increased plasma vasopressin by 6.9 +/- 1.3 pg/ml and reduced cardiac output by 14.4%. Skeletal muscle blood flow decreased by 32.8%, a pattern strikingly similar to that following vasopressin infusion. Obvious differences between vasopressin infusion and dehydration were also noted, in particular in the skin and splanchnic areas. However, the possibility that vasopressin contributed to the cardiovascular adjustments to dehydration must be considered. The use of an antagonist of the vascular effects of vasopressin, [1-deaminopenicillamine, 2-(O-methyl)tyrosine]arginine-vasopressin ([dPTyr(Me)]AVP), did not permit us to clarify this issue, because this analogue given alone exerted pronounced systemic and regional cardiovascular effects that resembled those of vasopressin.

Effects of hematocrit variations on regional hemodynamics and oxygen transport in the dog

1980 ◽  
Vol 238 (4) ◽  
pp. H545-H522 ◽  
Author(s):  
F. C. Fan ◽  
R. Y. Chen ◽  
G. B. Schuessler ◽  
S. Chien
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Blood Vessels ◽  
Oxygen Transport ◽  
Oxygen Supply ◽  
Blood Flows ◽  
Regional Hemodynamics ◽  
Regional Blood Flows ◽  
Splenic Vessels ◽  
The Brain

The responses of alterations in regional hemodynamics and oxygen transport rate to hematocrit (Hct) were studied in 20 pentobarbitalized dogs. Hemodilution was carried out by isovolemic exchange with plasma in 12 dogs and the hemoconcentration with packed cells in 8 dogs. The cardiac output and regional blood flows were determined with the microsphere technique. In hemodilution, the increases of blood flow to the myocardium and the brain were out of proportion to the increase of cardiac output; the oxygen supply to the myocardium remained unchanged while that to the brain decreased only slightly. In hemoconcentration, vasodilation occurred in the myocardium and the brain to maintain constant oxygen supply. Splenic vessels had marked vasoconstriction with Hct alteration in either direction. Blood vessels in the liver, intestine, and kidney responded with a milder vasoconstriction and maintained a constant oxygen supply between Hct of 30-55%. Therefore, during Hct alteration, redistribution of blood flow to myocardium and brain occurred. The optimal Hct range for constant oxygen supply was different among various organs.

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