The Effect of Lidocaine on Regional Blood Flows and Cardiac Output in the Non-Stressed and the Stressed Foetal Lamb

1986 ◽  
Vol 6 (3) ◽  
pp. 278
Author(s):  
C. Friesen ◽  
R. Yarnell ◽  
C. Bachman ◽  
R. Meatheral ◽  
D. Biehl
Keyword(s):  
Cardiac Output ◽  
Blood Flows ◽  
Regional Blood Flows ◽  
Foetal Lamb

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mum in diam) labeled with strontium-85 were injected into the left ventricle and known volumes of reference sample were withdrawn from peripheral arteries.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.

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.

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.

Regional Blood Flows in High-Cardiac-Output Hypertension

1980 ◽  
Vol 59 (s6) ◽  
pp. 355s-356s ◽  
Author(s):  
J. F. Liard
Keyword(s):  
Cardiac Output ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Initial Increase ◽  
Water Load ◽  
Blood Flows ◽  
Vascular Bed ◽  
Regional Blood Flows ◽  
Electromagnetic Flow Meter ◽  
Secondary Rise

1. Mean arterial pressure, cardiac output (electromagnetic flow-meter) and regional blood flows (15 μm radioactive microspheres) were measured repeatedly in eight dogs receiving a salt and water load after renal mass reduction as well as in six control animals. 2. As previously observed, hypertension developed in the salt-loaded dogs with an initial increase in cardiac output followed by a secondary rise in total peripheral resistance. 3. Much of the early increase in cardiac output was distributed to the skeletal muscle vascular bed. 4. Total peripheral resistance changes did not reflect the resistance of individual vascular beds in the early stages of salt and water load hypertension; indeed, resistance in the muscle vascular bed was decreased and that in the splanchnic area and the bone increased on the first day of salt and water load when total peripheral resistance was unchanged.

Regional blood flows and cardiac output distribution in rats during acute anemia or polycythemia

1980 ◽  
Vol 58 (4) ◽  
pp. 411-415 ◽  
Author(s):  
U. Ackermann ◽  
A. T. Veress
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Output ◽  
Metabolic Factors ◽  
Nervous Control ◽  
Blood Flows ◽  
Before And After ◽  
Regional Blood Flows ◽  
Normovolemic Anemia ◽  
Flow Changes ◽  
Vascular Beds

Radioactively labelled microspheres (15 μm diameter) were used to measure cardiac output (CO) distribution and blood flows in spleen, kidneys, and skeletal muscle before and after normovolemic anemia or polycythemia in anesthetized rats. Hematocrits were changed from 45 to 33% or from 45 to 59% by an exchange transfusion of homologous plasma or packed cells. Anemia was accompanied by a 39% increase in CO while polycythemia showed a 25% decrease. Following hemodilution the spleen as well as skeletal muscle received greater than normal fractions of CO and in each the flow increase was greater than expected from the fall in viscosity. The renal fraction of CO was unchanged. Following hemoconcentration "greater-than-normal" fractions of CO were distributed towards spleen and kidney. In these tissues the changes in flow were significantly greater than the change in resistance due to viscosity. Skeletal muscle flow changes appeared to have been due mostly to increased viscosity. These observations imply that during acute, isovolemic changes in hematocrit, the flow changes of individual vascular beds cannot be explained by viscosity changes alone but the importance of nervous control or of local metabolic factors remains to be investigated.

Regional blood flows in salt loading hypertension in the dog

1981 ◽  
Vol 240 (3) ◽  
pp. H361-H367 ◽  
Author(s):  
J. F. Liard
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Cardiac Output ◽  
Arterial Pressure ◽  
Muscle Blood Flow ◽  
Peripheral Resistance ◽  
Salt Loading ◽  
Skeletal Muscle Blood Flow ◽  
Blood Flows ◽  
Regional Blood Flows

An intravenous infusion of isotonic sodium chloride, 196 ml/kg per day, was administered for several days to eight dogs with their renal mass reduced. Mean arterial pressure, cardiac output (electromagnetic flowmeter), and regional blood flows (radioactive microspheres) were measured sequentially and the results compared with those obtained in six control dogs. The salt-loaded animals exhibited on the 1st day of the infusion a 25% increase of arterial pressure and cardiac output. Blood flows to the kidney, the splanchnic area, the skin, and the bone were not significantly changed, whereas skeletal muscle blood flow almost doubled. After several days, cardiac output returned toward control values but pressure remained elevated. Skeletal muscle blood flow, as most other regional flows, did not differ significantly from control values at that time. In four dogs studied 6 h after starting a faster saline infusion, most of the increase in cardiac output was also distributed to the skeletal muscle. Total peripheral resistance changes did not reflect the resistance of individual beds, because vasoconstriction appeared early in some areas but was masked by prominent, although transient, vasodilation in skeletal muscle.

Fever and regional blood flows in wethers and parturient ewes

1988 ◽  
Vol 65 (1) ◽  
pp. 165-172 ◽  
Author(s):  
C. M. Blatteis ◽  
J. R. Hales ◽  
A. A. Fawcett ◽  
T. A. Mashburn
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Regional Blood Flow ◽  
Flow Distribution ◽  
Full Term ◽  
Blood Flows ◽  
Pregnant Sheep ◽  
Regional Blood Flows ◽  
Placental Blood ◽  
Placental Blood Flow

To determine whether the reported absence of fever in full-term-pregnant ewes might be associated with shifts of regional blood flows from thermogenic tissues to placenta during this critical period, fevers were induced twice by injections of Escherichia coli lipopolysaccharide (LPS, 0.25 microgram/kg iv) into each of six Merino ewes from 8 to 1 days prepartum, and their regional blood flow distribution was measured with radioactive, 15-microns-diam microspheres before and during the rise in fever (when their rectal temperature had risen approximately 0.4 degree C). Unexpectedly, fever always developed, rising to heights not significantly different at any time before parturition [4-8 days prepartum = 0.81 +/- 0.23 degree C (SE); 1-3 days prepartum = 0.75 +/- 0.17 degree C) and similar to those in three wethers treated similarly (0.90 +/- 0.10 degree C). Generally, during rising fever, blood flow in the ewes shifted away from heat loss tissues (e.g., skin, nose) to heat production tissues (e.g., shivering muscle, fat) and cardiac output increased; blood flow through redistribution organs (e.g., splanchnic bed) decreased. The reverse occurred during defervescence. Utero-placental blood flow remained high in the febrile ewes. These regional blood flow distributions during febrigenesis and lysis are essentially the same as those during exposures to ambient cold and heat, respectively. Some differences in the responses of cardiac output and its redistribution, however, were apparent between wethers and pregnant ewes. We conclude that 1) the previously reported "absence of fever in the full-term-pregnant sheep" should not be regarded as a general phenomenon and 2) full-term-pregnant sheep support fever production without sacrificing placental blood flow.

Application of Physiologic Models to Predict the Influence of Changes in Body Composition and Blood Flows on the Pharmacokinetics of Fentanyl and Alfentanil in Patients 

1998 ◽  
Vol 88 (3) ◽  
pp. 657-667 ◽  
Author(s):  
Sven Bjorkman ◽  
Russell D. Wada ◽  
Donald Stanski
Keyword(s):  
Body Composition ◽  
Cardiac Output ◽  
Plasma Concentration ◽  
Plasma Concentrations ◽  
Pharmacokinetic Studies ◽  
Concentration Data ◽  
Blood Flows ◽  
Wide Range ◽  
Regional Blood Flows ◽  
Physiologic Models

Background The influence of changes in the physiologic state of a patient on the disposition of fentanyl and alfentanil is poorly understood. The aims of this study were to determine whether physiologic pharmacokinetic models for fentanyl and alfentanil, based on data from rats, could predict plasma concentrations of these opioids in humans and to determine how changes in physiology would influence the predictions of their disposition. Methods The predictions of the models were tested against plasma concentration data from published pharmacokinetic studies. The influences of changes in body composition, cardiac output, and regional blood flows on the disposition of the opioids were simulated. Results The models could predict independently measured plasma concentrations of the opioids after short infusions in humans. Simulations then predicted that differences in body composition between men and women would have little influence on the pharmacokinetics of the opioids. Changes in cardiac output would affect drug redistribution, and consequently the early decay of the plasma concentrations, but not markedly influence rates of elimination. Further, the clearance of the opioids would decrease and their volumes of distribution increase with the age of the patient, but this would only marginally affect the early disposition of the drugs. Even large fluctuations in peripheral or hepatic blood flows would have modest effects on arterial plasma concentrations of the opioids, and sudden "postoperative" increases in peripheral blood flows would cause minor secondary plasma concentration peaks. Conclusions The ability of the physiologic models to predict plasma concentrations of fentanyl and alfentanil in humans was confirmed. When changes in physiologic condition were simulated, effects on the pharmacokinetics of the opioids with possible implications for dosing were obtained only if cardiac output was varied over a wide range.

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