Cardiopulmonary reflexes and arterial pressure during rest and exercise in dogs

1983 ◽  
Vol 244 (3) ◽  
pp. H362-H369 ◽  
Author(s):  
S. C. Walgenbach ◽  
D. E. Donald
Keyword(s):  
Blood Pressure ◽  
Arterial Pressure ◽  
Aortic Arch ◽  
Arterial Blood Pressure ◽  
Blood Pressure Response ◽  
General Level ◽  
Arterial Blood ◽  
Cervical Vagotomy ◽  
The Moment ◽  
Cardiopulmonary Receptors

Mean arterial blood pressure, heart rate, and cardiac output were monitored at rest and during exercise of two grades of severity in conscious dogs under control conditions and after progressive interruption of the baroreflexes. Aortic arch denervation and vascular isolation and pressurization of the carotid sinuses were used to interrupt arterial baroreflexes. Subsequent interruption of cardiopulmonary afferents was produced by acute bilateral cervical vagotomy. The results indicate that 1) with the cardiopulmonary receptors alone operative, the arterial blood pressure response to exercise is abnormal, 2) cardiopulmonary receptors do not contribute to the moment-to-moment modulation of arterial pressure, and 3) the carotid sinuses, aortic arch, and cardiopulmonary receptors are all involved in determining the mean level of arterial blood pressure. It is concluded that vagally innervated cardiopulmonary receptors do not have a significant role in regulating arterial blood pressure during exercise but are involved in establishing the general level of arterial blood pressure.

Cardiopulmonary reflexes and blood pressure in exercising sinoaortic-denervated dogs

1984 ◽  
Vol 57 (5) ◽  
pp. 1417-1421 ◽  
Author(s):  
D. A. Daskalopoulos ◽  
J. T. Shepherd ◽  
S. C. Walgenbach
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Vagal Afferents ◽  
Systemic Resistance ◽  
Vigorous Exercise ◽  
Arterial Blood ◽  
Resistance Vessels ◽  
Before And After ◽  
Cervical Vagotomy ◽  
Cardiopulmonary Receptors

To examine the role of cardiopulmonary receptors in arterial blood pressure regulation during and after exercise, conscious dogs with chronic sinoaortic denervation were subjected to 12 min of light exercise and 12 min of exercise that increased in severity every 3 min. Hemodynamic measurements were made before and after interruption of cardiopulmonary afferents by bilateral cervical vagotomy. During both exercise protocols, after an initial transient decrease, the arterial blood pressure remained close to resting values before and after vagotomy. On cessation of the graded exercise, the arterial blood pressure did not change before, but a rapid and sustained increase in pressure occurred after vagotomy. At the time of this increase the cardiac output and heart rate were returning rapidly to the resting level. The study demonstrates that in the chronic absence of arterial baroreflexes, vagal afferents prevent a rise in arterial blood pressure after vigorous exercise presumably by the action of cardiopulmonary receptors causing a rapid dilatation of systemic resistance vessels.

scholarly journals Plasticity in breathing and arterial blood pressure following acute intermittent hypercapnic hypoxia in infant rat pups with a partial loss of 5-HT neurons

2015 ◽  
Vol 309 (10) ◽  
pp. R1273-R1284 ◽  
Author(s):  
Jennifer Magnusson ◽  
Kevin J. Cummings
Keyword(s):  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Arterial Blood Pressure ◽  
Cardiovascular Responses ◽  
Partial Loss ◽  
Rat Pups ◽  
Arterial Blood ◽  
Hypercapnic Hypoxia ◽  
Long Term Facilitation

The role of serotonin (5-HT) neurons in cardiovascular responses to acute intermittent hypoxia (AIH) has not been studied in the neonatal period. We hypothesized that a partial loss of 5-HT neurons would reduce arterial blood pressure (BP) at rest, increase the fall in BP during hypoxia, and reduce the long-term facilitation of breathing (vLTF) and BP following AIH. We exposed 2-wk-old, 5,7-dihydroxytryptamine-treated and controls to AIH (10% O2; n = 13 control, 14 treated), acute intermittent hypercapnia (5% CO2; n = 12 and 11), or acute intermittent hypercapnic hypoxia (AIHH; 10% O2, 5% CO2; n = 15 and 17). We gave five 5-min challenges of AIH and acute intermittent hypercapnia, and twenty ∼20-s challenges of AIHH to mimic sleep apnea. Systolic BP (sBP), diastolic BP, mean arterial pressure, heart rate (HR), ventilation (V̇e), and metabolic rate (V̇o2) were continuously monitored. 5,7-Dihydroxytryptamine induced an ∼35% loss of 5-HT neurons from the medullary raphe. Compared with controls, pups deficient in 5-HT neurons had reduced resting sBP (∼6 mmHg), mean arterial pressure (∼5 mmHg), and HR (56 beats/min), and experienced a reduced drop in BP during hypoxia. AIHH induced vLTF in both groups, reflected in increased V̇e and V̇e/V̇o2, and decreased arterial Pco2. The sBP of pups deficient in 5-HT neurons, but not controls, was increased 1 h following AIHH. Our data suggest that a relatively small loss of 5-HT neurons compromises resting BP and HR, but has no influence on ventilatory plasticity induced by AIHH. AIHH may be useful for reversing cardiorespiratory defects related to partial 5-HT system dysfunction.

GRANGER CAUSALITY ANALYSIS BETWEEN INTRA-OSSEOUS PRESSURE AND ARTERIAL BLOOD PRESSURE IN AFRICAN GREY PARROTS (PSITTACUS ERITHACUS)

2021 ◽  
pp. 1-8
Author(s):  
Yi-Tse Hsiao ◽  
Yun-Wen Peng ◽  
Pin Huan Yu
Keyword(s):  
Blood Pressure ◽  
Arterial Pressure ◽  
Granger Causality ◽  
Arterial Blood Pressure ◽  
Pressure Measurement ◽  
Direct Method ◽  
Blood Pressure Measurement ◽  
Rational Approach ◽  
Arterial Blood ◽  
The Relationship

Monitoring blood pressure helps a clinical veterinarian assess various conditions in birds. Blood pressure is not only a bio-indicator of renal or cardiovascular disease but is also a vital indicator for anesthesia. Anesthetic- and sedation-related mortality is higher in birds than dogs or cats. The traditional method of blood pressure measurement in mammals mainly relies on indirect methods. However, indirect blood pressure measurement is not reliable in birds, making the direct method the only gold standard. Although an arterial catheter can provide continuous real-time arterial pressure in birds, the method requires technical skill and is limited by bird size, and is thus not practical in birds with circulatory collapse. Intra-osseous (IO) blood pressure is potentially related to arterial pressure and may be a much easier and safer technique that is less limited by animal size. However, the relationship between IO pressure and arterial blood pressure has not been established. This study used mathematical methods to determine the relationship between IO pressure and arterial blood pressure. The Granger causality (G.C.) theory was applied in the study and used to analyze which pressure signal was leading the other. Our findings suggest that IO pressure is G.C. by arterial blood pressure; thus, the use of IO pressure measurements as an alternative to arterial blood pressure measurement is a rational approach.

Effect of the Ace Inhibitor Ceronapril on Cerebral Blood flow in Hypertensive Patients

1996 ◽  
Vol 30 (6) ◽  
pp. 578-582 ◽  
Author(s):  
Neal R Cutler ◽  
John J Sramek ◽  
Azucena Luna ◽  
Ismael Mena ◽  
Eric P Brass ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Diastolic Blood Pressure ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Enzyme Inhibitor ◽  
Blood Pressure Response ◽  
Combined Therapy ◽  
Arterial Blood

Objective To assess the effect of the angiotensin-converting enzyme inhibitor ceronapril on cerebral blood flow (CBF) in patients with moderate hypertension. Design Patients received chlorthalidone 25 mg for 4 weeks, and if diastolic blood pressure remained in the range of 100–115 mm Hg, they were given titrated doses of ceronapril (10–40 mg/d based on blood pressure response) in addition to chlorthalidone for 9 weeks. Setting Outpatient research clinic. Subjects Eligible patients had moderate essential hypertension (diastolic blood pressure 100–115 mm Hg) assessed when the patients were receiving no medications. Thirteen patients were entered into the study; 1 withdrew for reasons unrelated to the study drug. Twelve patients (11 men, 1 woman; mean age 52 y) completed the study. Intervention Ceronapril, given with chlorthalidone. Main Outcome Measures CBF measurements were taken at the start and end of ceronapril therapy using intravenous 133Xe; blood pressures were determined weekly. Results Mean arterial blood pressure decreased from 130 ± 4 to 120 ±7 mm Hg after 4 weeks of chlorthalidone administration, and fell further to 108 ± 8 mm Hg after an additional 9 weeks of combined chlorthalidone-ceronapril therapy (p < 0.05). CBF fell from 44 ± 15 to 34 ± 5 mL/min/100 g during the 9 weeks of combined therapy (p = 0.05). No adverse effects consistent with decreased CBF were observed. The decrease in CBF was not linearly correlated with the change in systemic blood pressure, but was strongly correlated (r = –0.937; p < 0.001) with the initial CBF. Conclusions The decrease in mean arterial blood pressure was not associated with a decrease in CBF. Patients with high CBF may be predisposed to a decrease in CBF when treated with ceronapril and chlorthalidone.

Increases in intramuscular pressure raise arterial blood pressure during dynamic exercise

2001 ◽  
Vol 91 (5) ◽  
pp. 2351-2358 ◽  
Author(s):  
K. M. Gallagher ◽  
P. J. Fadel ◽  
S. A. Smith ◽  
K. H. Norton ◽  
R. G. Querry ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Arterial Blood Pressure ◽  
Dynamic Exercise ◽  
Positive Pressure ◽  
Intramuscular Pressure ◽  
Arterial Blood ◽  
Exercise In Humans ◽  
Cuff Occlusion

This investigation was designed to determine the role of intramuscular pressure-sensitive mechanoreceptors and chemically sensitive metaboreceptors in affecting the blood pressure response to dynamic exercise in humans. Sixteen subjects performed incremental (20 W/min) cycle exercise to fatigue under four conditions: control, exercise with thigh cuff occlusion of 90 Torr (Cuff occlusion), exercise with lower body positive pressure (LBPP) of 45 Torr, and a combination of thigh cuff occlusion and LBPP (combination). Indexes of central command (heart rate, oxygen uptake, ratings of perceived exertion, and electromyographic activity), cardiac output, stroke volume, and total peripheral resistance were not significantly different between the four conditions. Mechanical stimulation during LBPP and combination conditions resulted in significant elevations in intramuscular pressure and mean arterial pressure from control at rest and throughout the incremental exercise protocol ( P < 0.05). Conversely, there existed no significant changes in mean arterial pressure when the metaboreflex was stimulated by cuff occlusion. These findings suggest that under normal conditions the mechanoreflex is tonically active and is the primary mediator of exercise pressor reflex-induced alterations in arterial blood pressure during submaximal dynamic exercise in humans.

Muscle chemoreflex alters vascular conductance in nonischemic exercising skeletal muscle

1994 ◽  
Vol 77 (6) ◽  
pp. 2761-2766 ◽  
Author(s):  
S. W. Mittelstadt ◽  
L. B. Bell ◽  
K. P. O'Hagan ◽  
P. S. Clifford
Keyword(s):  
Blood Pressure ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Blood Pressure Response ◽  
Pressor Response ◽  
Vascular Conductance ◽  
Arterial Blood ◽  
Response To Exercise ◽  
Muscle Chemoreflex

Previous studies have shown that the muscle chemoreflex causes an augmented blood pressure response to exercise and partially restores blood flow to ischemic muscle. The purpose of this study was to investigate the effects of the muscle chemoreflex on blood flow to nonischemic exercising skeletal muscle. During each experiment, dogs ran at 10 kph for 8–16 min and the muscle chemoreflex was evoked by reducing hindlimb blood flow at 4-min intervals (0–80%). Arterial blood pressure, hindlimb blood flow, forelimb blood flow, and forelimb vascular conductance were averaged over the last minute at each level of occlusion. Stimulation of the muscle chemoreflex caused increases in arterial blood pressure and forelimb blood flow and decreases in forelimb vascular conductance. The decrease in forelimb vascular conductance demonstrates that the muscle chemoreflex causes vasoconstriction in the nonischemic exercising forelimb. Despite the decrease in vascular conductance, the increased driving pressure caused by the pressor response was large enough to produce an increased forelimb blood flow.

Association between Intraoperative Hypotension and Myocardial Injury after Vascular Surgery

2016 ◽  
Vol 124 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Judith A. R. van Waes ◽  
Wilton A. van Klei ◽  
Duminda N. Wijeysundera ◽  
Leo van Wolfswinkel ◽  
Thomas F. Lindsay ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Surgery ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Myocardial Injury ◽  
Arterial Blood ◽  
Intraoperative Hypotension ◽  
Cumulative Duration

Abstract Background Postoperative myocardial injury occurs frequently after noncardiac surgery and is strongly associated with mortality. Intraoperative hypotension (IOH) is hypothesized to be a possible cause. The aim of this study was to determine the association between IOH and postoperative myocardial injury. Methods This cohort study included 890 consecutive patients aged 60 yr or older undergoing vascular surgery from two university centers. The occurrence of myocardial injury was assessed by troponin measurements as part of a postoperative care protocol. IOH was defined by four different thresholds using either relative or absolute values of the mean arterial blood pressure based on previous studies. Either invasive or noninvasive blood pressure measurements were used. Poisson regression analysis was used to determine the association between IOH and postoperative myocardial injury, adjusted for potential clinical confounders and multiple comparisons. Results Depending on the definition used, IOH occurred in 12 to 81% of the patients. Postoperative myocardial injury occurred in 131 (29%) patients with IOH as defined by a mean arterial pressure less than 60 mmHg, compared with 87 (20%) patients without IOH (P = 0.001). After adjustment for potential confounding factors including mean heart rates, a 40% decrease from the preinduction mean arterial blood pressure with a cumulative duration of more than 30 min was associated with postoperative myocardial injury (relative risk, 1.8; 99% CI, 1.2 to 2.6, P &lt; 0.001). Shorter cumulative durations (less than 30 min) were not associated with myocardial injury. Postoperative myocardial infarction and death within 30 days occurred in 26 (6%) and 17 (4%) patients with IOH as defined by a mean arterial pressure less than 60 mmHg, compared with 12 (3%; P = 0.08) and 15 (3%; P = 0.77) patients without IOH, respectively. Conclusions In elderly vascular surgery patients, IOH defined as a 40% decrease from the preinduction mean arterial blood pressure with a cumulative duration of more than 30 min was associated with postoperative myocardial injury.

The Blood Pressure Cuff Controversy

PEDIATRICS ◽  
1978 ◽  
Vol 61 (1) ◽  
pp. 161-161
Author(s):  
Myron L. Cohen ◽  
Harold Alexander ◽  
Leonard Steinfeld
Keyword(s):  
Blood Pressure ◽  
Arterial Pressure ◽  
Arterial Blood Pressure ◽  
Infants And Children ◽  
Blood Pressure Cuff ◽  
Arterial Blood ◽  
Pressure Cuff ◽  
In Infants And Children ◽  
Occlusive Cuff

In a letter (Pediatrics 59:138, January 1977) Bailie noted that the sizes of cuffs normally available for the measurement of blood pressure in infants and children are inadequate to insure that measuremnents will accurately reflect the true arterial blood pressure. In general the use of an improperly sized cuff will lead to an overestimation of the arterial blood pressure. In recent studies,1,2 we have shown that several criteria must be fulfilled in the design of an occlusive cuff in order to insure that the indirect pressure accurately reflects the arterial pressure.

Does nitric oxide buffer arterial blood pressure variability in humans?

2002 ◽  
Vol 93 (4) ◽  
pp. 1466-1470 ◽  
Author(s):  
William H. Cooke ◽  
Rong Zhang ◽  
Julie H. Zuckerman ◽  
Jian Cui ◽  
Thad E. Wilson ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Arterial Pressure ◽  
Arterial Blood Pressure ◽  
Animal Studies ◽  
Transfer Functions ◽  
Body Position ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Arterial Blood

Animal studies suggest that nitric oxide (NO) plays an important role in buffering short-term arterial pressure variability, but data from humans addressing this hypothesis are scarce. We evaluated the effects of NO synthase (NOS) inhibition on arterial blood pressure (BP) variability in eight healthy subjects in the supine position and during 60° head-up tilt (HUT). Systemic NOS was blocked by intravenous infusion of N G-monomethyl-l-arginine (l-NMMA). Electrocardiogram and beat-by-beat BP in the finger (Finapres) were recorded continuously for 6 min, and brachial cuff BP was recorded before and after l-NMMA in each body position. BP and R-R variability and their transfer functions were quantified by power spectral analysis in the low-frequency (LF; 0.05–0.15 Hz) and high-frequency (HF; 0.15–0.35 Hz) ranges.l-NMMA infusion increased supine BP (systolic, 109 ± 4 vs. 122 ± 3 mmHg, P = 0.03; diastolic, 68 ± 2 vs. 78 ± 3 mmHg, P = 0.002), but it did not affect supine R-R interval or BP variability. Beforel-NMMA, HUT decreased HF R-R variability ( P= 0.03), decreased transfer function gain (LF, 12 ± 2 vs. 5 ± 1 ms/mmHg, P = 0.007; HF, 18 ± 3 vs. 3 ± 1 ms/mmHg, P = 0.002), and increased LF BP variability ( P < 0.0001). After l-NMMA, HUT resulted in similar changes in BP and R-R variability compared with tilt without l-NMMA. Increased supine BP afterl-NMMA with no effect on BP variability during HUT suggests that tonic release of NO is important for systemic vascular tone and thus steady-state arterial pressure, but NO does not buffer dynamic BP oscillations in humans.

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