Quantitative Evaluation of the Circulatory Adjustment of Splenectomized Dogs to Hemorrhage

1958 ◽  
Vol 193 (3) ◽  
pp. 605-614 ◽  
Author(s):  
Shu Chien
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Blood Volume ◽  
Sympathetic Activity ◽  
Volume Reduction ◽  
Fluid Replacement ◽  
Maximum Heart Rate ◽  
Equal Importance ◽  
Sympathetic Nervous ◽  
The Relationship

Controlled, single hemorrhages were carried out in splenectomized dogs (5–49% of blood volume) and sympathectomized-splenectomized dogs (5–32% of blood volume). A linear relationship exists between the degree of hemodilution and the amount of hemorrhage in both groups. Sympathetic activity aids in the fluid replacement after hemorrhage. In the sympathectomized-splenectomized dogs, the relationship between arterial pressure and blood volume reduction seems to be nonlinear. Arterial pressure of the splenectomized dogs does not decrease until blood volume reduction is more than 10%. Thereafter it decreases linearly with increasing volume reduction which is still compatible with life. In hemorrhages between 10 and 40% of blood volume, the roles played by sympathetic activity and hemodilution in the maintenance of arterial pressure are of about equal importance. The increase in heart rate after hemorrhage has S-shaped relationship to both blood volume reduction and arterial pressure decrease in dogs with or without sympathetic nervous system. The maximum heart rate displayed by sympathectomized dogs after hemorrhage (about 120 beats/min.) is much less than that of the dogs with sympathetic system intact (about 215 beats/min.). The activation of sympathetic activity is not fully achieved immediately after hemorrhage.

Rat venular pressure-diameter relationships are regulated by sympathetic activity

1990 ◽  
Vol 259 (3) ◽  
pp. H674-H680 ◽  
Author(s):  
A. A. Shoukas ◽  
H. G. Bohlen
Keyword(s):  
Blood Volume ◽  
Sympathetic Activity ◽  
Volume Expansion ◽  
Venous Pressure ◽  
Nervous System Activity ◽  
Blood Volume Expansion ◽  
Capacitance Characteristics ◽  
Sympathetic Nervous ◽  
Relationship Of ◽  
The Relationship

The hypothesis that the pressure-diameter relationship of intestinal venules in rats is primarily determined by sympathetic nervous system activity was tested. The pressure-diameter relationship of the smallest to largest diameter (20-100 microns) intestinal venules of the rat was measured at rest, during hemorrhage to increase sympathetic neural activity, and during saline volume expansion to decrease sympathetic activity. During hemorrhage, the diameter of all venules decreased approximately 10% at 10 mmHg venous pressure, and the slope of the pressure-diameter relationship increased approximately 50% above control. Blood volume expansion led to an approximately 10% increase in venule diameter at 10 mmHg and a 25% decrease in slope. Denervation of the vessels causes concomitant vasodilation, which was greater than the vasodilation caused by blood volume expansion. Hemorrhage after denervation caused no significant changes in the relationship when compared with denervated control. Nitroprusside caused an even greater vasodilation when compared with the pressure-diameter relationship after denervation. The results suggest that the slope and 10-mmHg intercept of the pressure-diameter relationship for the largest through smallest intestinal venules and, therefore, their vascular compliance and capacitance characteristics are primarily determined by sympathetic activity.

Effect of hemorrhage on cardiac output of sympathectomized dogs

1961 ◽  
Vol 201 (3) ◽  
pp. 475-479 ◽  
Author(s):  
Shu Chien ◽  
Stuart Billig
Keyword(s):  
Cardiac Output ◽  
Arterial Pressure ◽  
Blood Volume ◽  
Sympathetic Activity ◽  
Peripheral Resistance ◽  
Vascular Wall ◽  
Equal Importance ◽  
Metabolic Products ◽  
Before And After ◽  
Flow Pressure

Blood volume, cardiac output (C.O.), and arterial pressure were measured in unanesthetized, sympathectomized dogs before and after various degrees of hemorrhage. The posthemorrhage cardiac output, expressed as a percentage of the control, showed a linear relationship with the per cent reduction in blood volume (Vr), (C.O. = 107 – 2.51 Vr). After a moderate hemorrhage, the per cent decrease in the arterial pressure was less than that of the cardiac output, indicating a rise of peripheral resistance. This is attributed mainly to the distensibility of the vascular wall. After more severe hemorrhages, the peripheral resistance tended to decrease, due probably to the reduction in hematocrit and the accumulation of metabolic products. By analyzing the volume-flow-pressure relationship in sympathectomized dogs, one can quantify the various compensatory adjustments to hemorrhage. When the blood volume is reduced by less than 10%, the arterial pressure is maintained primarily by the nonneural factors. With a volume reduction between 10 and 25%, the sympathetic activity, the inhibition of vagi, and the nonneural factors are of about equal importance. When the reduction of blood volume is greater than 25%, the sympathetic activity becomes the most significant compensatory factor.

scholarly journals SIMULATION OF THE RELATIONSHIP BETWEEN EXERCISE AND CARDIOPULMONARY FUNCTION AT HIGH ALTITUDE

2021 ◽  
Vol 27 (5) ◽  
pp. 509-513
Author(s):  
Rui Li
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Oxygen Saturation ◽  
High Altitude ◽  
Lower Limb ◽  
Pulmonary Circulation ◽  
Blood Oxygen ◽  
Blood Oxygen Saturation ◽  
Cardiopulmonary Function ◽  
The Relationship

ABSTRACT Introduction: Due to various uncertain and unexpected factors in life such as diseases, natural disasters, traffic accidents, and congenital disabilities, the number and proportion of lower limb amputations are still rising for many reasons, so the research on lower limb prostheses is particularly important. Objective: This work aimed to study the relationship between altitude exercise and cardiopulmonary function. Methods: A model of abnormal changes in cardiopulmonary function was established, and then 40 plateau exercisers were selected, all of whom arrived in Tibet in March 2017. The relationship between pulmonary circulation volume and internal pressure in the chest was observed and compared. The relationship between cardiopulmonary sensory reflex and exercise (high altitude) breathing and heart rate was analyzed. A comparison of the cardiopulmonary function of subjects of different genders was implemented. Moreover, the influence of different altitudes on the subjects’ cardiopulmonary function and the subjects’ cardiopulmonary function changes before departure and during the first, second, and third week after departure were observed and compared. Results: I. As the pressure in the thoracic cavity increased, the subjects’ pulmonary circulation blood volume gradually decreased, and the decrease was most obvious in the stage of thoracic pressure −50 to 0. II. As the cardiorespiratory reflex coefficient increased, the subjects’ breathing and heart rate compensatory acceleration appeared. III. Tracking and monitoring of the subjects’ cardiopulmonary indicators revealed that with the increase in altitude, the subjects’ average arterial pressure, respiratory frequency, and heart rate all showed an upward trend, while the blood oxygen saturation value showed a downward trend. IV. No matter how high the altitude was, the average arterial pressure, respiratory rate, and heart rate monitored of the subjects under exercise were significantly superior to the indicator values under resting state. In contrast, the blood oxygen saturation value showed the opposite trend. V. The subjects’ average arterial pressure, respiration, and heart rate in the first week were higher than other periods, but the blood oxygen saturation was relatively lower. In the second and third weeks, the changes in cardiopulmonary function were relatively smooth (all P<0.05). VI. The changes in the index of the cardiopulmonary function of subjects of different genders were small (p>0.05). Conclusion: Through modeling, the results of the plateau environment on the cardiopulmonary function of the body were made clearer, and these research data provided theoretical references for the training of the sports field in the plateau area. Level of evidence II; Therapeutic studies - investigation of treatment results.

Ovine fetal adrenal gland and cardiovascular function

1988 ◽  
Vol 254 (4) ◽  
pp. R706-R710 ◽  
Author(s):  
N. D. Ray ◽  
C. S. Turner ◽  
N. M. Rawashdeh ◽  
J. C. Rose
Keyword(s):  
Heart Rate ◽  
Adrenal Gland ◽  
Arterial Pressure ◽  
Blood Volume ◽  
Cardiovascular Function ◽  
Late Gestation ◽  
Arterial Blood ◽  
Significant Difference ◽  
Ovine Fetus ◽  
Ovine Fetal

Given the necessity of the adrenal gland in maintaining cardiovascular function in adults of various species, these experiments were conducted to determine if fetal bilateral adrenalectomy results in altered resting heart rate, hypotension, and decreased basal blood volume as well as a diminished ability of the fetus to maintain arterial pressure and restore blood volume in response to hemorrhage. We studied heart rate, arterial blood pressure, and blood volume changes in response to hemorrhage of 20% of blood volume at 2%/min in seven adrenalectomized and six intact chronically cannulated unanesthetized lambs between 119 and 133 days of gestation. Blood volumes and percent restitution of shed volume were determined using 51Cr-tagged red blood cells and changes in hematocrit. There was no significant difference between groups in basal heart rate, mean arterial pressure, hematocrit, and blood volume. The two groups were similar to hemorrhage-induced changes in these and restitution of volume. Therefore, fetal adrenal glands are not necessary for basal cardiovascular function or regulation subsequent to moderate hemorrhage in the late gestation ovine fetus.

Arterial baroreflex resetting mediates postexercise reductions in arterial pressure and heart rate

1998 ◽  
Vol 275 (5) ◽  
pp. H1627-H1634 ◽  
Author(s):  
Margaret P. Chandler ◽  
David W. Rodenbaugh ◽  
Stephen E. DiCarlo
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Acute Exercise ◽  
Operating Point ◽  
Arterial Baroreflex ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Single Bout ◽  
Before And After ◽  
The Relationship

We tested the hypothesis that postexercise reductions in arterial pressure and heart rate (HR) are mediated by a lowering of the operating point and a reduction in the gain of the arterial baroreflex. To test this hypothesis, spontaneous changes in arterial pressure and the reflex responses of HR were examined before and after a single bout of mild to moderate dynamic exercise in 19 spontaneously hypertensive rats (SHR, 10 male and 9 female). Eleven SHR subjected to sinoaortic denervation (SAD) (6 male, 5 female) were also studied. All rats were instrumented with an arterial catheter for the measurement of arterial pressure and HR. After exercise, arterial pressure and HR were reduced below preexercise levels. Furthermore, the operating point and spontaneous gain (G) of the arterial baroreflex were reduced. Specifically, after exercise, the spontaneous range of HR (P1, 50%), the pressure at the midpoint of the pressure range (P3, 13%) and the HR at the midpoint of the HR range (H3, 10%), the spontaneous minimum HR (P4, 8%) and maximum HR (10%), and G (76%) were significantly attenuated. SAD significantly attenuated the relationship between arterial pressure and HR by reducing G (males 94%, females 95%). These results demonstrate that acute exercise resulted in a postexercise resetting of the operating point and a reduction in the gain of the arterial baroreflex. Furthermore, these data suggest that postexercise reductions in arterial pressure and HR are mediated by a lowering of the operating point of the arterial baroreflex.

A model for the genesis of arterial pressure Mayer waves from heart rate and sympathetic activity

2001 ◽  
Vol 91 (1-2) ◽  
pp. 62-75 ◽  
Author(s):  
Christopher W Myers ◽  
Michael A Cohen ◽  
Dwain L Eckberg ◽  
J.Andrew Taylor
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Sympathetic Activity ◽  
Mayer Waves

Maternal responses to long-term hypoxemia in sheep

1989 ◽  
Vol 256 (6) ◽  
pp. R1340-R1347 ◽  
Author(s):  
T. Kitanaka ◽  
R. D. Gilbert ◽  
L. D. Longo
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Blood Volume ◽  
Cardiovascular Responses ◽  
Uterine Blood Flow ◽  
O2 Uptake ◽  
Arterial Po2

To determine the maternal cardiovascular responses to long-term hypoxemia, we studied three groups of animals: 1) pregnant ewes (n = 20) at 110-115 days gestation subjected to hypoxia for up to 28 days; 2) pregnant ewes (n = 4) that served as normoxic controls; and 3) nonpregnant ewes (n = 6) subjected to hypoxemia for up to 28 days. We measured mean arterial pressure, heart rate, uterine blood flow, and uterine vascular resistance continuously for 1 h/day while the ewe was exposed to an inspired O2 fraction of 12-13% for at least 17 days. Arterial PO2, O2 saturation, hemoglobin, arteriovenous O2 difference, and uterine O2 uptake were measured daily while blood volume and erythropoietin concentration were measured weekly. In the pregnant hypoxic group arterial PO2 decreased from a control value of 101.5 +/- 5.1 to 59.2 +/- 5.1 Torr within a few minutes, where it remained throughout the study. The hemoglobin concentration increased from 8.9 +/- 0.5 to 10.0 +/- 0.5 g/dl within 24 h where it remained, whereas erythropoietin concentration increased from 16.6 +/- 2.1 to 39.1 +/- 7.8 mU/ml at 24 h but then returned to near-control levels. Arterial glucose concentration, mean arterial pressure, and cardiac output decreased slightly but insignificantly. In contrast, body weight, heart rate, blood volume, uterine blood flow, uterine O2 flow, uteroplacental O2 uptake, and the concentrations of catecholamines and cortisol remained relatively constant. Thus both pregnant and nonpregnant sheep experience relatively minor cardiovascular and hematologic responses in response to long-term hypoxemia of moderate severity.

Spinal cord regulation of sympathetic activity in intact and spinal rats

1994 ◽  
Vol 266 (4) ◽  
pp. H1485-H1493 ◽  
Author(s):  
Y. Hong ◽  
D. F. Cechetto ◽  
L. C. Weaver
Keyword(s):  
Spinal Cord ◽  
Heart Rate ◽  
Arterial Pressure ◽  
Sympathetic Activity ◽  
Excitatory Amino Acid ◽  
Intrathecal Injection ◽  
Cardiovascular Responses ◽  
Homocysteic Acid ◽  
Arterial Blood ◽  
Cord Injury

Excitatory amino acid (EAA) and cholinergic neurotransmission in the spinal cord of urethan-anesthetized rats was investigated to assess mechanisms regulating sympathetic activity after spinal cord injury. Blockade of EAA transmission by intrathecal injection of kynurenic acid decreased arterial blood pressure by 24 +/- 4 mmHg, heart rate by 15 +/- 10 beats/min, and renal sympathetic nerve activity (RSNA) by 85 +/- 4% in intact rats. In rats with cervical spinal transections, this blockade decreased RSNA by 51 +/- 5% and had no effect on arterial pressure and heart rate. Muscarinic blockade by intrathecal atropine decreased RSNA by 12 +/- 3 and 32 +/- 6% in intact and spinal rats, respectively, and caused no cardiovascular responses in either group. Combined blockade of EAA and muscarinic receptors in spinal rats decreased RSNA by 77 +/- 1%. Intrathecal injections of the EAA agonist D,L-homocysteic acid in spinal rats caused initial increases (335 +/- 28%) in RSNA lasting approximately 3 min and later sustained increases (157 +/- 19%) lasting 36 +/- 8 min. Only the early excitation increased arterial pressure by 17 +/- 3 mmHg, and then pressure returned to baseline values. The EAA agonist kainic acid increased RSNA by 402 +/- 90% in spinal rats, an effect lasting 70 +/- 5 min, and increased arterial pressure by only 8 +/- 2 mmHg for 12 +/- 5 min. These findings suggest that tonic activity of spinal neurons with EAA and cholinergic receptors maintains tonic RSNA after spinal cord transection. However, this activity does not play a major role in maintaining arterial pressure, even if it is increased substantially by EAA receptor stimulation.

Perceived Exertion and Metabolic Responses of Women during Aerobic Dance Exercise

1995 ◽  
Vol 81 (2) ◽  
pp. 691-700
Author(s):  
Sarah A. Schaefeer ◽  
Lynn A. Darby ◽  
Kathy D. Browder ◽  
Brenda D. Reeves
Keyword(s):  
Heart Rate ◽  
Perceived Exertion ◽  
Metabolic Responses ◽  
Maximum Heart Rate ◽  
Ratings Of Perceived Exertion ◽  
Aerobic Dance ◽  
Partial Correlations ◽  
Metabolic Variables ◽  
Instructional Experience ◽  
The Relationship

The relationship between ratings of perceived exertion (RPE) and metabolic responses was examined during aerobic dance exercise with combined arm and leg movements. 16 women with previous aerobic dance instructional experience performed three consecutive trials of 8 min. each of aerobic dance exercise at a cadence of 124 and 138 beats • min.-1 Estimates of RPE reported at the end of each trial were significantly different across the trials while heart rate and % maximum heart rate were significantly different between Trials 1 and 3. Correlations and partial correlations between RPE and all metabolic variables were not significant across trials and with trials combined except for ventilation. Results indicated that RPE should not be used singularly as an indicator of exercise intensity during aerobic dance exercise.

Increased osmolality of conscious water-deprived rats supports arterial pressure and sympathetic activity via a brain action

2005 ◽  
Vol 288 (5) ◽  
pp. R1248-R1255 ◽  
Author(s):  
Virginia L. Brooks ◽  
Yue Qi ◽  
Theresa L. O'Donaughy
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Sympathetic Activity ◽  
Carotid Arteries ◽  
Sympathetic Nerve Activity ◽  
Nerve Activity ◽  
Fluid Infusion ◽  
Hypotonic Fluid ◽  
Control Heart ◽  
The Brain

To test the hypothesis that high osmolality acts in the brain to chronically support mean arterial pressure (MAP) and lumbar sympathetic nerve activity (LSNA), the osmolality of blood perfusing the brain was reduced in conscious water-deprived and water-replete rats by infusion of hypotonic fluid via bilateral nonoccluding intracarotid catheters. In water-deprived rats, the intracarotid hypotonic infusion, estimated to lower osmolality by ∼2%, decreased MAP by 9 ± 1 mmHg and LSNA to 86 ± 7% of control; heart increased by 25 ± 8 beats per minute (bpm) (all P < 0.05). MAP, LSNA, and heart rate did not change when the hypotonic fluid was infused intravenously. The intracarotid hypotonic fluid infusion was also ineffective in water-replete rats. Prior treatment with a V1 vasopressin antagonist did not alter the subsequent hypotensive and tachycardic effects of intracarotid hypotonic fluid infusion in water-deprived rats. In summary, acute decreases in osmolality of the carotid blood of water-deprived, but not water-replete, rats decreases MAP and LSNA and increases heart rate. These data support the hypothesis that the elevated osmolality induced by water deprivation acts via a region perfused by the carotid arteries, presumably the brain, to tonically increase MAP and LSNA and suppress heart rate.

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