Cardiovascular functions in the dog rewarmed rapidly and slowly from deep hypothermia

1960 ◽  
Vol 198 (2) ◽  
pp. 333-335 ◽  
Author(s):  
H. E. D'Amato ◽  
Suzanne Kronheim ◽  
B. G. Covino
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Superior Vena ◽  
Vena Cava ◽  
Deep Hypothermia ◽  
Cardiovascular Collapse ◽  
Cardiovascular Failure ◽  
Myocardial Failure ◽  
Cardiovascular Functions

Heart rate, blood pressure, cardiac output and cardiac minute work were measured in pentobarbitalized dogs prior to induction of hypothermia, at rectal temperatures of 25°C or 20°C and following rapid rewarming in warm water or slow rewarming by wrapping in heated sheeting. During rapid rewarming from either 25°C or 20°C no consistent failure in recovery of normal cardiovascular function was observed, although 1 out of 10 dogs did suffer cardiovascular collapse during rapid rewarming. Slow rewarming from 25° and 20°C resulted in consistent failure of some or all of these functions to recover to prehypothermic levels. Moreover, 5 out of 15 slowly rewarmed dogs suffered cardiovascular collapse during the rewarming process. In five dogs slowly rewarmed from 20°C saline was infused into the superior vena cava. This procedure resulted in moderate increases in blood pressure but dramatic increases in cardiac output and minute work (200% and 270%, respectively), thereby negating myocardial failure as the primary cause of the occasionally observed cardiovascular failure.

Assessment of superior vena cava flow and cardiac output in different patterns of patent ductus arteriosus shunt

2021 ◽  
Author(s):  
Adrianne Rahde Bischoff ◽  
Regan E. Giesinger ◽  
Amy H. Stanford ◽  
Ravi Ashwath ◽  
Patrick J. McNamara
Keyword(s):  
Cardiac Output ◽  
Patent Ductus Arteriosus ◽  
Superior Vena Cava ◽  
Superior Vena ◽  
Ductus Arteriosus ◽  
Vena Cava ◽  
Patent Ductus

Increased cardiac output following occlusion of the descending thoracic aorta in dogs

1982 ◽  
Vol 243 (1) ◽  
pp. R152-R158 ◽  
Author(s):  
J. K. Stene ◽  
B. Burns ◽  
S. Permutt ◽  
P. Caldini ◽  
M. Shanoff
Keyword(s):  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Thoracic Aorta ◽  
Vascular System ◽  
Superior Vena ◽  
Vena Cava ◽  
Right Atrial ◽  
Mean Systemic Pressure ◽  
Extracorporeal Bypass

Occlusion of the thoracic aorta (AO) in dogs with a constant volume right ventricular extracorporeal bypass increased cardiac output (Q) by 43% and mean arterial pressure by 46%, while mean systemic pressure (MSP) was unchanged. We compared AO with occlusion of the brachiocephalic and left subclavian arteries (BSO) which decreased cardiac output by 5%, increased mean arterial pressure by 32%, and increased MSP by 11%. We feel these results confirm that AO elevates preload by transferring blood volume from the splanchnic veins to the vascular system drained by the superior vena cava. If the heart is competent to keep right arterial pressure at or near zero, this increase in preload will elevate Q above control levels. Comparing our data with results of other authors who have not controlled right atrial pressure, emphasizes the importance of a competent right ventricle in allowing venous return to determine Q.

A Comparison of the Acute Haemodynamic Effects of Propranolol and Pindolol at Rest and during Supine Exercise in Man

1980 ◽  
Vol 59 (s6) ◽  
pp. 465s-468s ◽  
Author(s):  
T. L. Svendsen ◽  
J. E. Carlsen ◽  
O. Hartling ◽  
A. McNair ◽  
J. Trap-Jensen
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Pulmonary Artery ◽  
Pulmonary Artery Pressure ◽  
Response Curves ◽  
Receptor Blocking ◽  
Artery Pressure ◽  
Arterial Blood ◽  
Β Receptor

1. Dose-response curves for heart rate, cardiac output, arterial blood pressure and pulmonary artery pressure were obtained in 16 male patients after intravenous administration of three increasing doses of pindolol, propranolol or placebo. All patients had an uncomplicated acute myocardial infarction 6–8 months earlier. 2. The dose-response curves were obtained at rest and during repeated bouts of supine bicycle exercise. The cumulative dose amounted to 0.024 mg/kg body weight for pindolol and to 0.192 mg/kg body weight for propranolol. 3. At rest propranolol significantly reduced heart rate and cardiac output by 12% and 15% respectively. Arterial mean blood pressure was reduced by 9.2 mmHg. Mean pulmonary artery pressure increased significantly by 2 mmHg. Statistically significant changes in these variables were not seen after pindolol or placebo. 4. During exercise pindolol and propranolol both reduced cardiac output, heart rate and arterial blood pressure to the same extent. After propranolol mean pulmonary artery pressure was increased significantly by 3.6 mmHg. Pindolol and placebo did not change pulmonary artery pressure significantly. 5. The study suggests that pindolol may offer haemodynamic advantages over β-receptor-blocking agents without intrinsic sympathomimetic activity during low activity of the sympathetic nervous system, and may be preferable in situations where the β-receptor-blocking effect is required only during physical or psychic stress.

Characterization of baroreflex impairment in conscious dogs with pacing-induced heart failure

1993 ◽  
Vol 265 (5) ◽  
pp. R1132-R1140 ◽  
Author(s):  
N. B. Olivier ◽  
R. B. Stephenson
Keyword(s):  
Heart Failure ◽  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Peripheral Resistance ◽  
Open Loop ◽  
Ventricular Pacing ◽  
Baroreflex Control ◽  
Rapid Ventricular Pacing ◽  
Reflex Control

Open-loop baroreflex responses were evaluated in eight conscious dogs before and during congestive heart failure to determine the effects of failure on baroreflex control of blood pressure, heart rate, cardiac output, and total peripheral resistance. Heart failure was induced by rapid ventricular pacing. Baroreflex function was determined by calculation of the range and gain of the open-loop stimulus-response relationships for the effect of carotid sinus pressure on blood pressure, heart rate, cardiac output, and total peripheral resistance. The range and gain of blood pressure responses were substantially reduced as early as 3 days after induction of heart failure (161 +/- 6 to 99 +/- 8 mmHg and -2.7 +/- 0.3 to -1.5 +/- 0.1, respectively) and remained depressed for the 21 days of heart failure. This depression in baroreflex control of blood pressure was associated with similar depressions in reflex range and gain for heart rate (125 +/- 9 to 78 +/- 11 beats/min and -2.05 +/- 0.2 to -1.16 +/- 0.2 beats/min, respectively) and cardiac output (1.74 +/- 0.2 to 0.46 +/- 0.2 l/min and -0.81 +/- 0.02 to -0.027 +/- 0.008 l/min, respectively). The group-averaged range and gain for reflex control of vascular resistance were not altered by heart failure. In three dogs, discontinuation of rapid ventricular pacing led to resolution of heart failure within 7 days and partial restoration of the range and gain of reflex control of blood pressure. We conclude that heart failure reversibly depresses baroreflex control of blood pressure principally through a concurrent reduction in reflex control of cardiac output, whereas reflex control of vascular resistance is not consistently affected.

scholarly journals Role of the Melanocortin System in the Central Regulation of Cardiovascular Functions

2021 ◽  
Vol 12 ◽  
Author(s):  
Francesca Copperi ◽  
Jung Dae Kim ◽  
Sabrina Diano
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Energy Homeostasis ◽  
Current Knowledge ◽  
Protective Role ◽  
System Level ◽  
Central Regulation ◽  
Melanocortin System ◽  
Cardiovascular Functions

Increasing evidence indicates that the melanocortin system is not only a central player in energy homeostasis, food intake and glucose level regulation, but also in the modulation of cardiovascular functions, such as blood pressure and heart rate. The melanocortins, and in particular α- and γ-MSH, have been shown to exert their cardiovascular activity both at the central nervous system level and in the periphery (e.g., in the adrenal gland), binding their receptors MC3R and MC4R and influencing the activity of the sympathetic nervous system. In addition, some studies have shown that the activation of MC3R and MC4R by their endogenous ligands is able to improve the outcome of cardiovascular diseases, such as myocardial and cerebral ischemia. In this brief review, we will discuss the current knowledge of how the melanocortin system influences essential cardiovascular functions, such as blood pressure and heart rate, and its protective role in ischemic events, with a particular focus on the central regulation of such mechanisms.

The Chanages of Blood Pressure , Heart Rate and Cardiac Output During Awake Fiberoptic Nasotracheal and Orotracheal Intubation

1991 ◽  
Vol 24 (3) ◽  
pp. 505
Author(s):  
Young Jin Lim ◽  
Jae Hyon Bahk ◽  
Kook Hyun Lee ◽  
Jin Kyu Park ◽  
Kwang Won Yum
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Orotracheal Intubation

Pet CO2 inversely affects MSNA response to orthostatic stress

2001 ◽  
Vol 281 (3) ◽  
pp. H1040-H1046 ◽  
Author(s):  
J. Kevin Shoemaker ◽  
Debbie D. O'Leary ◽  
Richard L. Hughson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Orthostatic Intolerance ◽  
Muscle Sympathetic Nerve Activity ◽  
Peripheral Resistance ◽  
Burst Frequency ◽  
Head Up Tilt ◽  
End Tidal ◽  
Combined Data

Arterial hypocapnia has been associated with orthostatic intolerance. Therefore, we tested the hypothesis that hypocapnia may be detrimental to increases in muscle sympathetic nerve activity (MSNA) and total peripheral resistance (TPR) during head-up tilt (HUT). Ventilation was increased ∼1.5 times above baseline for each of three conditions, whereas end-tidal Pco 2 (Pet CO2 ) was clamped at normocapnic (Normo), hypercapnic (Hyper; +5 mmHg relative to Normo), and hypocapnic (Hypo; −5 mmHg relative to Normo) conditions. MSNA (microneurography), heart rate, blood pressure (BP, Finapres), and cardiac output (Q, Doppler) were measured continuously during supine rest and 45° HUT. The increase in heart rate when changing from supine to HUT ( P < 0.001) was not different across Pet CO2 conditions. MSNA burst frequency increased similarly with HUT in all conditions ( P < 0.05). However, total MSNA and the increase in total amplitude relative to baseline (%ΔMSNA) increased more when changing to HUT during Hypo compared with Hyper ( P < 0.05). Both BP and Q were higher during Hyper than both Normo and Hypo (main effect; P < 0.05). Therefore, the MSNA response to HUT varied inversely with levels of Pet CO2 . The combined data suggest that augmented cardiac output with hypercapnia sustained blood pressure during HUT leading to a diminished sympathetic response.

Effect of sympathetic blockade on diurnal variation of hemodynamic patterns

1989 ◽  
Vol 256 (3) ◽  
pp. R778-R785 ◽  
Author(s):  
M. I. Talan ◽  
B. T. Engel
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Base Line ◽  
Sympathetic Blockade ◽  
Selective Blockade ◽  
Arterial Blood

Heart rate, stroke volume, and intra-arterial blood pressure were monitored continuously in each of four monkeys, 18 consecutive h/day for several weeks. The mean heart rate, stroke volume, cardiac output, systolic and diastolic blood pressure, and total peripheral resistance were calculated for each minute and reduced to hourly means. After base-line data were collected for approximately 20 days, observation was continued for equal periods of time under conditions of alpha-sympathetic blockade, beta-sympathetic blockade, and double sympathetic blockade. This was achieved by intra-arterial infusion of prazosin, atenolol, or a combination of both in concentration sufficient for at least 75% reduction of response to injection of agonists. The results confirmed previous findings of a diurnal pattern characterized by a fall in cardiac output and a rise in total peripheral resistance throughout the night. This pattern was not eliminated by selective blockade, of alpha- or beta-sympathetic receptors or by double sympathetic blockade; in fact, it was exacerbated by sympathetic blockade, indicating that the sympathetic nervous system attenuates these events. Because these findings indicate that blood volume redistribution is probably not the mechanism mediating the observed effects, we have hypothesized that a diurnal loss in plasma volume may mediate the fall in cardiac output and that the rise in total peripheral resistance reflects a homeostatic regulation of arterial pressure.

Supine exercise restores arterial blood pressure and skin blood flow despite dehydration and hyperthermia

1999 ◽  
Vol 277 (2) ◽  
pp. H576-H583 ◽  
Author(s):  
José González-Alonso ◽  
Ricardo Mora-Rodríguez ◽  
Edward F. Coyle
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Arterial Blood Pressure ◽  
Blood Volume ◽  
Plasma Catecholamines ◽  
Central Blood Volume ◽  
Vascular Conductance ◽  
Arterial Blood ◽  
Cutaneous Vascular Conductance

We determined whether the deleterious effects of dehydration and hyperthermia on cardiovascular function during upright exercise were attenuated by elevating central blood volume with supine exercise. Seven trained men [maximal oxygen consumption (V˙o 2 max) 4.7 ± 0.4 l/min (mean ± SE)] cycled for 30 min in the heat (35°C) in the upright and in the supine positions (V˙o 2 2.93 ± 0.27 l/min) while maintaining euhydration by fluid ingestion or while being dehydrated by 5% of body weight after 2 h of upright exercise. When subjects were euhydrated, esophageal temperature (Tes) was 37.8–38.0°C in both body postures. Dehydration caused equal hyperthermia during both upright and supine exercise (Tes = 38.7–38.8°C). During upright exercise, dehydration lowered stroke volume (SV), cardiac output, mean arterial pressure (MAP), and cutaneous vascular conductance and increased heart rate and plasma catecholamines [30 ± 6 ml, 3.0 ± 0.7 l/min, 6 ± 2 mmHg, 22 ± 8%, 14 ± 2 beats/min, and 50–96%, respectively; all P < 0.05]. In contrast, during supine exercise, dehydration did not cause significant alterations in MAP, cutaneous vascular conductance, or plasma catecholamines. Furthermore, supine versus upright exercise attenuated the increases in heart rate (7 ± 2 vs. 9 ± 1%) and the reductions in SV (13 ± 4 vs. 21 ± 3%) and cardiac output (8 ± 3 vs. 14 ± 3%) (all P< 0.05). These results suggest that the decline in cutaneous vascular conductance and the increase in plasma norepinephrine concentration, independent of hyperthermia, are associated with a reduction in central blood volume and a lower arterial blood pressure.

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