scholarly journals THE PHYSIOLOGICAL RESPONSE OF THE CIRCULATORY SYSTEM TO EXPERIMENTAL ALTERATIONS

1925 ◽  
Vol 42 (5) ◽  
pp. 661-679 ◽  
Author(s):  
Emile Holman ◽  
Claude S. Beck
Keyword(s):  
Blood Pressure ◽  
Blood Volume ◽  
Peripheral Resistance ◽  
Circulatory System ◽  
Blood Stream ◽  
Volume Flow ◽  
Volume Control ◽  
Total Blood ◽  
Full Compensation ◽  
The Right

An abnormal communication, experimentally produced between the right and left ventricles, causes a deflection of part of the blood stream into the shorter pulmonary circuit. Proceeding pari passu with the increase in volume flow of blood through this shorter circuit, there occurs a gradual enlargement of the heart limited to that part of the circulatory system through which the deflected blood passes; namely, the left ventricle, the right ventricle, the pulmonary artery, and the left auricle. There is also a demonstrable hypertrophy of the right and left ventricles, which presumably is the result of the increased effort necessary to propel forward an increased volume flow of blood, since it cannot be attributed to an increased peripheral resistance. Immediately after the production of the defect, the right auricle and aorta become smaller than usual, conforming in size to the decreased volume flow of blood through them. As full compensation for the deflected flow occurs by an increase in total blood volume, they return to their normal size. If full compensation has not occurred they remain smaller than normal (Dog X 11). The changes incident to the establishment of an opening in the septum are entirely dependent upon the size of the defect, and hence, upon the extent of the volume of blood deflected into the shorter circuit. Commensurate with the volume of blood deflected, there is a fall in general blood pressure. If the animal survives the immediate fall in blood pressure, certain compensatory adjustments occur which reestablish a more normal blood pressure: (a) an immediate increase in pulse rate; (b) a gradual increase in total blood mass. The increase in blood volume is directly commensurate with the size of the defect. The pulse returns to a normal rate when complete compensation through an increase in blood volume has been attained. It is suggested that the enlargement of the heart seen clinically in so called "idiopathic hypertrophy," "essential hypertension," and also in certain cases of cardiorenal disease, may be due to an increase in total blood mass following some interference with the mechanism for its control. The seat of this impairment in blood volume control may be: (a) in a chemical alteration in the blood; (b) in a diseased function of the kidneys which may be responsible for a decreased elimination, or for a change in the chemical composition of the blood; or (c) in an abnormal stimulation of the organs producing the cellular elements of the blood.

scholarly journals STUDIES ON EXPERIMENTAL PLETHORA IN DOGS AND RABBITS

1922 ◽  
Vol 35 (6) ◽  
pp. 847-871 ◽  
Author(s):  
Edward B. Krumbhaar ◽  
Alfred Chanutin
Keyword(s):  
Bone Marrow ◽  
Lymph Nodes ◽  
Blood Volume ◽  
Total Nitrogen ◽  
Circulatory System ◽  
Liver Parenchyma ◽  
Blood Stream ◽  
Experimental Conditions ◽  
Total Blood ◽  
Blood Pigment

1. The effects of repeated transfusions of blood on the blood-destroying and blood-forming apparatus of normal and splenectomized dogs and rabbits have been described. An anemia which developed despite continued blood transfusions in two dogs splenectomized during plethora has also been studied. 2. The decrease or absence of reticulocytes from the blood stream during plethora and their increase during "plethoric anemia" are evidently due to depression and activation of bone marrow activity. The response of the bone marrow is not immediate upon the onset of anemia, but is delayed for several days. 3. The blood volume studies have served to emphasize the constancy of plasma volume under extreme experimental conditions, and the adaptability of the circulatory system to large increases in total blood volume. 4. Blood destruction and elimination, as measured by urobilin excretion, are greatly increased during the stage of plethora, but still more so during "plethoric anemia." 5. Despite intravenous introductions of large quantities of nitrogen in the form of whole blood, the total nitrogen, urea, and ammonia in the urine and feces are not raised appreciably for some time after the onset of plethora. The normal organism is apparently able to store large quantities of blood or its decomposition products. Upon the onset of a "plethoric anemia," there is an increase in urinary total nitrogen and urea excretion, which was lowered during the course of the anemia. Albuminuria is also found at this time. Other nitrogenous constituents and phosphates show no striking changes. 6. Blood pigment, chiefly in the form of hemosiderin, is deposited in enormous quantities in the spleen, liver, lymph nodes, and bone marrow. It occurs chiefly in phagocytes, though in late stages large extracellular masses are found. Increased pigment deposition can still be found several months after transfusions have been stopped. 7. Phagocytes containing erythrocytes are found rarely, if at all, and only in the acute cases, but their occurrence may be greatly masked by the coexistent congestion. 8. In splenectomized dogs the tendency to "plethoric anemia" is much more apparent, although a direct connection between the two events is not established. In rabbits, whose spleens constitute only 0.05 per cent of body weight, "plethoric anemia" is more easily produced. 9. In splenectomized animals pigment-bearing phagocytes are especially prominent in the liver, although lymph nodes and bone marrow apparently share in the extra work caused by the absence of the spleen. Lymph nodes with some of the characteristics of hemolymph nodes were found in various localities in all animals that had been made plethoric. 10. In rabbits blood pigment is deposited in the hemopoietic organs in large amounts, but under the conditions of our experiments, the picture and the experiment have been constantly complicated by early fatal intravascular agglutination and thrombosis. In the rabbit, as in human hemochromatosis, the pigment is found in two forms: hemosiderin granules, and smaller, dark spicules that do not react to the usual iron stains (probably hernofuscin). The latter pigment is also found seeded through the cells of the liver parenchyma.

Long-term hemodynamic actions of atrial natriuretic factor (99-126) in conscious sheep

1988 ◽  
Vol 254 (4) ◽  
pp. H811-H815 ◽  
Author(s):  
D. G. Parkes ◽  
J. P. Coghlan ◽  
J. G. McDougall ◽  
B. A. Scoggins
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Blood Volume ◽  
Total Peripheral Resistance ◽  
Atrial Natriuretic Factor ◽  
Peripheral Resistance ◽  
Natriuretic Factor ◽  
Atrial Natriuretic

The hemodynamic and metabolic effects of long-term (5 day) infusion of human atrial natriuretic factor (ANF) were examined in conscious chronically instrumented sheep. Infusion of ANF at 20 micrograms/h, a rate below the threshold for an acute natriuretic effect, decreased blood pressure by 9 +/- 1 mmHg on day 5, associated with a fall in calculated total peripheral resistance. On day 1, ANF reduced cardiac output, stroke volume, and blood volume, effects that were associated with an increase in heart rate and calculated total peripheral resistance and a small decrease in blood pressure. On days 4 and 5 there was a small increase in urine volume and sodium excretion. On day 5 an increase in water intake and body weight was observed. No change was seen in plasma concentrations of renin, arginine vasopressin, glucose, adrenocorticotropic hormone, or protein. This study suggests that the short-term hypotensive effect of ANF results from a reduction in cardiac output associated with a fall in both stroke volume and effective blood volume. However, after 5 days of infusion, ANF lowers blood pressure via a reduction in total peripheral resistance.

Heterogeneity of gut capillary transit times and impaired gut oxygen extraction in endotoxemic pigs

1996 ◽  
Vol 81 (2) ◽  
pp. 895-904 ◽  
Author(s):  
M. F. Humer ◽  
P. T. Phang ◽  
B. P. Friesen ◽  
M. F. Allard ◽  
C. M. Goddard ◽  
...  
Keyword(s):  
Blood Volume ◽  
Transit Time ◽  
Volume Flow ◽  
Oxygen Extraction ◽  
Control Group ◽  
Total Blood Volume ◽  
Oxygen Extraction Ratio ◽  
Total Blood ◽  
Transit Times ◽  
Critical Oxygen

We tested the hypothesis that endotoxin increases the heterogeneity of gut capillary transit times and impairs oxygen extraction. The gut critical oxygen extraction ratio was determined by measuring multiple oxygen delivery-consumption points during progressive phlebotomy in eight control and eight endotoxin-infused anesthetized pigs. In multiple 1- to 2-g samples of small bowel, we measured blood volume (radiolabeled red blood cells) and flow (radiolabeled 15-microns microspheres) before and after critical oxygen extraction. Red blood cell transit time (= volume/flow) multiplied by morphologically determined capillary/total blood volume gave capillary transit time. During hemorrhage, capillary/total blood volume did not change in the endotoxin group (0.5 +/- 4.5%) but increased in the control group (17.6 +/- 2.5%; P < 0.05) due to a decrease in total gut blood volume. Flow decreased significantly in the endotoxin group (36 +/- 10%; P < 0.05) but not in the control group (12 +/- 10%). Capillary transit-time heterogeneity increased in the endotoxin group (12.3 +/- 4.9%) compared with the control group (-5.8 +/- 7.4%; P < 0.05), predicting a critical oxygen extraction ratio 0.14 lower in the endotoxin group than in the control group (K. R. Walley. J. Appl. Physiol. 81: 885–894, 1996). This matches the measured difference (endotoxin group, 0.60 +/- 0.04; control group, 0.74 +/- 0.03; P < 0.05). Increased heterogeneity of capillary transit times may be an important cause of impaired oxygen extraction.

Estimation of blood pressure-related parameters by electrical impedance measurement

1992 ◽  
Vol 73 (5) ◽  
pp. 1946-1957 ◽  
Author(s):  
J. H. Muntinga ◽  
K. R. Visser
Keyword(s):  
Blood Pressure ◽  
Blood Volume ◽  
Electrical Impedance ◽  
Cuff Pressure ◽  
Arterial Compliance ◽  
Blood Pressure Measurement ◽  
Venous Blood ◽  
Impedance Measurement ◽  
Total Blood ◽  
Arterial Blood

In 13 healthy volunteers a computerized experimental set-up was used to measure the electrical impedance of the upper arm at changing cuff pressure, together with the finger arterial blood pressure in the contralateral arm. On the basis of a model for the admittance response, the arterial blood volume per centimeter length (1.4 +/- 0.3 ml/cm), the venous blood volume as a percentage of the total blood compartment (49.2 +/- 12.6%), and the total arterial compliance as a function of mean arterial transmural pressure were estimated. The effective physiological arterial compliance amounted to 2.0 +/- 1.3 microliters.mmHg-1.cm-1 and the maximum compliance to 33.4 +/- 12.0 microliters.mmHg-1.cm-1. Additionally, the extravascular fluid volume expelled by the occluding cuff (0.3 +/- 0.3 ml/cm) was estimated. These quantities are closely related to patient-dependent sources of an unreliable blood pressure measurement and vary with changes in cardiovascular function, such as those found in hypertension. Traditionally, a combination of several methods is needed to estimate them. Such methods, however, usually neglect the contribution of extravascular factors.

Influence of atrial natriuretic factor on intravascular volume displacement in pigs

1990 ◽  
Vol 259 (5) ◽  
pp. H1595-H1600
Author(s):  
D. L. Rutlen ◽  
G. Christensen ◽  
K. G. Helgesen ◽  
A. Ilebekk
Keyword(s):  
Blood Volume ◽  
Urine Output ◽  
Atrial Natriuretic Factor ◽  
Fluid Loss ◽  
Total Blood Volume ◽  
Right Heart ◽  
Total Blood ◽  
Reservoir Volume ◽  
Natriuretic Factor ◽  
The Right

The present study was undertaken to quantitate the influences of transcapillary fluid loss, urine output, and the capacity vessels on volume displacement toward and away from the right heart during atrial natriuretic factor (ANF) administration. In eight anesthetized pigs undergoing carotid denervation, cervical vagotomy, and splenectomy, blood was drained from the venae cavae to an extracorporeal reservoir and returned to the right atrium at a constant rate so that volume displacement toward and away from the heart could be recorded as change in reservoir volume. Human ANF-(99-126) (0.1 micrograms.kg-1.min-1) for 15 min was associated with a decrease in reservoir volume of 2.7 +/- 0.4 ml/kg (P less than 0.05), which resulted from a decrease in total blood volume of 8.6 +/- 1.0 ml/kg (P less than 0.05) and a displacement from the capacitance vasculature of 5.9 +/- 1.3 ml/kg (P less than 0.05). Since urine output increased only slightly, virtually all of the total blood volume decrement was due to a displacement of fluid into the extravascular space. Thus ANF acts to displace volume away from the right heart. The displacement is due almost entirely to an increase in transcapillary fluid loss; however, volume displacement from the capacity vessels to the right heart partially counteracts this transcapillary influence.

Haemodynamic and Blood Volume Studies in Long-Term Haemodialysis Patients, and in Patients with Successfully Transplanted Kidneys

1973 ◽  
Vol 45 (s1) ◽  
pp. 155s-157s
Author(s):  
J. Tuckman ◽  
J.-L. Benninger ◽  
F. Reubi
Keyword(s):  
Mean Arterial Pressure ◽  
Cardiac Index ◽  
Arterial Pressure ◽  
Blood Volume ◽  
Peripheral Resistance ◽  
Total Blood Volume ◽  
Total Blood ◽  
Transplanted Kidneys ◽  
Very High

1. Stabilized hypertensive haemodialysis patients, as well as those with normotension, had a greatly elevated cardiac index (CI) that was not due to hypervolemia, but was most likely secondary to their anaemic condition. The hypertension itself was not accompanied by hypervolaemia, but was associated with a relatively very high total peripheral resistance. 2. In eight patients with successfully transplanted kidneys the following results were found. (a) Five were clearly hypertensive and had supine mean arterial pressure between 117 and 143 mmHg. It is noted that they were receiving prednisone at the time of the studies. (b) CI was normal in seven. (c) Total blood volume was normal in all. (d) The presence of wide-open arterio-venous fistulae was not associated with an increase in CI.

scholarly journals Postural hypocapnic hyperventilation is associated with enhanced peripheral vasoconstriction in postural tachycardia syndrome with normal supine blood flow

2006 ◽  
Vol 291 (2) ◽  
pp. H904-H913 ◽  
Author(s):  
Julian M. Stewart ◽  
Marvin S. Medow ◽  
Neil S. Cherniack ◽  
Benjamin H. Natelson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Blood Volume ◽  
Peripheral Resistance ◽  
Impedance Plethysmography ◽  
Postural Tachycardia Syndrome ◽  
Peripheral Vasoconstriction ◽  
Postural Tachycardia ◽  
End Tidal

Previous investigations have demonstrated a subset of postural tachycardia syndrome (POTS) patients characterized by normal peripheral resistance and blood volume while supine but thoracic hypovolemia and splanchnic blood pooling while upright secondary to splanchnic hyperemia. Such “normal-flow” POTS patients often demonstrate hypocapnia during orthostatic stress. We studied 20 POTS patients (14–23 yr of age) and compared them with 10 comparably aged healthy volunteers. We measured changes in heart rate, blood pressure, heart rate and blood pressure variability, arm and leg strain-gauge occlusion plethysmography, respiratory impedance plethysmography calibrated against pneumotachography, end-tidal partial pressure of carbon dioxide (PetCO2), and impedance plethysmographic indexes of blood volume and blood flow within the thoracic, splanchnic, pelvic (upper leg), and lower leg regional circulations while supine and during upright tilt to 70°. Ten POTS patients demonstrated significant hyperventilation and hypocapnia (POTSHC) while 10 were normocapnic with minimal increase in postural ventilation, comparable to control. While relative splanchnic hypervolemia and hyperemia occurred in both POTS groups compared with controls, marked enhancement in peripheral vasoconstriction occurred only in POTSHC and was related to thoracic blood flow. Variability indexes suggested enhanced sympathetic activation in POTSHC compared with other subjects. The data suggest enhanced cardiac and peripheral sympathetic excitation in POTSHC.

Blood volume changes in rodents exposed to simulated high altitude

1961 ◽  
Vol 200 (3) ◽  
pp. 523-526 ◽  
Author(s):  
Adam Anthony ◽  
Judy Kreider
Keyword(s):  
Blood Volume ◽  
Plasma Volume ◽  
Circulatory System ◽  
Dilution Method ◽  
Total Blood Volume ◽  
Total Blood ◽  
Altitude Exposure ◽  
Volume Measurements ◽  
Capillary Bed ◽  
Rats And Mice

Blood volume measurements were made in rats and mice exposed to a simulated altitude of 20,000– 22,000 ft. for periods of 1–4 weeks. The noncapillary blood volume (which includes arteries, veins, arterioles and venules) was determined from plastic-corrosion preparations of the circulatory system. The plasma volume and total blood volume were measured using the T-1824 dye dilution method and capillary volume was calculated by subtracting noncapillary volume from total blood values. The increase in volume of the noncapillary vessels of rats and mice was about 1–2 ml/100 gm body weight after 1–4 weeks of altitude exposure. It was also shown that the total blood volume of acclimatized rats is about 40% greater than that of control animals whereas the plasma volume decreases by about 57%. It was concluded that altitude exposure resulted in a greater increase in the capacity of the noncapillary vessels ( ca. 60%) than in that of the capillary bed ( ca. 25%).

Impaired Autonomic Blood Pressure and Blood Volume Control in Chronic Renal Failure

2010 ◽  
pp. 291-297
Author(s):  
Guido Grassi ◽  
Raffaella Dell’Oro ◽  
Fosca Quarti-Trevano ◽  
Giuseppe Mancia
Keyword(s):  
Blood Pressure ◽  
Renal Failure ◽  
Chronic Renal Failure ◽  
Blood Volume ◽  
Volume Control ◽  
Blood Volume Control

IMMEDIATE EFFECTS OF RAPID HEMORRHAGE ON HEMODYNAMICS IN THE DOG

1956 ◽  
Vol 34 (5) ◽  
pp. 827-834
Author(s):  
Russell A. Waud ◽  
Douglas R. Waud
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Index ◽  
Specific Gravity ◽  
Blood Cell ◽  
Cell Count ◽  
Blood Volume ◽  
Sedimentation Rate ◽  
Color Index ◽  
Peripheral Resistance

Dogs were anesthetized by the intravenous injection of sodium pentobarbital. Viscosity, hematocrit, blood pressure, cardiac index, stroke output, cardiac output, heart rate, peripheral resistance, red blood cell count, blood volume/body surface area, cell volume/area, plasma volume/area, plasma protein, hemoglobin, specific gravity of whole blood, cell size, color index, and sedimentation rate were determined in 16 dogs, before and following hemorrhage, and in seven controls. The following points were demonstrated: following hemorrhage the viscosity, hematocrit, blood pressure, stroke output, minute output, blood volume, and cell volume were markedly decreased. The decrease in blood volume, by limiting the venous return, was probably the cause of the decreased minute output and fall in blood pressure; this, by reducing the capillary flow, deprived the tissues of an adequate supply of oxygen. There was no significant change in the heart rate. The total peripheral resistance (T.P.R.) was greatly increased. The fall in hematocrit indicates a hemodilution which was probably the main factor in reducing the viscosity. It would appear that the decreased blood volume was the primary cause of the fall in blood pressure following hemorrhage and that a lowering of viscosity was not a large factor. There was no significant change following hemorrhage in the cardiac index, color index, cell size, white cell count, specific gravity of plasma, or sedimentation rate.

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