Preeclampsia is not associated with elevated muscle sympathetic reactivity.

2020 ◽  
Author(s):  
Laura Marcela Reyes ◽  
Charlotte W. Usselman ◽  
Rshmi Khurana ◽  
Radha S. Chari ◽  
Michael K. Stickland ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Pregnant Women ◽  
Gestational Age ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Tonic Activity ◽  
Sympathetic Nervous ◽  
Peripheral Chemoreflex

Objective: To determine whether increased chemoreflex tonic activity is associated with augmented muscle sympathetic nervous sys activity (MSNA) in women diagnosed with preeclampsia. Methods: Women with preeclampsia (n=19; 32±5 years old, 31±3 weeks gestation) were matched by age and gestational age with pregnant women (controls, n=38, 32±4 years old, 31±4 weeks gestation; 2:1 ratio). MSNA (n=9 preeclampsia) was assessed during baseline, peripheral chemoreflex de-activation (hyperoxia) and a cold pressor test (CPT). Baroreflex gain, diastolic blood pressure at which there is a 50% likelihood of MSNA occurring (T50) and plasma noradrenaline concentrations were measured. Results: Baseline mean arterial pressure (MAP: 106±11 vs. 87±10 mmHg, p<0.0001), noradrenaline concentrations (498±152 pg/mL vs. 326±147, p=0.001) and T50 (79±7 vs. 71±9 mmHg, p=0.02) were greater in women with preeclampsia compared to controls. However, baseline MSNA (burst incidence [BI]: 41±16 vs. 45±13 bursts/100hb, p=0.4) was not different between groups. Responses to hyperoxia (ΔBI -5±7 vs. -1±8 bursts/100hb, p=0.1; ΔMAP -1±3 vs. -2±3 mmHg, p=0.7) and CPT (ΔBI 15±7 vs. 12±11 bursts/100hb, p=0.6; ΔMAP 10±4 vs. 12±11 mmHg, p=0.6) were not different between groups. Conclusion: Our findings question the assumption that increased MSNA contributes to hypertension in women with preeclampsia. The chemoreflex does not appear to contribute to an increase in MSNA in women with preeclampsia.

scholarly journals Acute Cardiovascular Effects of Epidural Spinal Cord Stimulation

2007 ◽  
Vol 5;10 (9;5) ◽  
pp. 677-685
Author(s):  
David M. Schultz
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Spinal Cord Stimulation ◽  
Statistical Significance ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Arterial Blood

Background: Several animal studies support the contention that thoracic spinal cord stimulation (SCS) might decrease arterial blood pressure. Objective: To determine if electrical stimulation of the dorsal spinal cord in humans will lower mean arterial pressure (MAP) and heart rate (HR). Design: Case Series Methods: Ten normotensive subjects that were clinically indicated for SCS testing were studied. Two of the 10 patients who underwent testing were excluded from the analysis because they did not respond to the Cold Pressor Test (CPT). Systolic blood pressure, diastolic blood pressure, and heart rate were measured continuously at the wrist (using the Vasotrac device). SCS was administered with quadripolar leads implanted into the epidural space under fluoroscopic guidance. SCS was randomly performed either in the T1-T2 or T5-T6 region of the spinal cord during normal conditions as well as during transient stress induced by CPT. The CPT was conducted by immersing the non-dominant hand in ice-cold water for 2 minutes. Results: There were moderate decreases in MAP and HR during SCS at the T5-T6 region compared to baseline that did not reach statistical significance. However, SCS at the T1-T2 region tended to increase MAP and HR compared to baseline but the change did not reach statistical significance. Arterial blood pressure was transiently elevated by 9.4 ± 3.8 mmHg using CPT during the control period with SCS turned off and also during SCS at either the T1-T2 region or T5-T6 region of the spinal cord (by 9.2 ± 5 mmHg and 10.7 ± 8.4 mmHg, respectively). During SCS at T5-T6, the CPT significantly increased MAP by 5.9±7.1 mmHg compared to control CPT (SCS off). Conclusion: This study demonstrated that SCS at either the T1-T2 or T5-T6 region did not significantly alter MAP or HR compared to baseline (no SCS). However, during transcient stress (elevated sympathetic tone) induced by CPT, there was a significant increase in MAP and moderate decrease in HR during SCS at T5-T6 region, which is not consistent with previous data in the literature. Acute SCS did not result in adverse cardiovascular responses and proved to be safe. Key words: Spinal cord stimulation, mean arterial pressure, heart rate, cold pressor test

Cutaneous Vascular Responses Evoked in the Hand by the Cold Pressor Test and by Mental Arithmetic

1990 ◽  
Vol 79 (1) ◽  
pp. 43-50 ◽  
Author(s):  
I. Marriott ◽  
Janice M. Marshall ◽  
E. J. Johns
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Mental Arithmetic ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Pressor Test ◽  
Contralateral Hand ◽  
The Right ◽  
Cutaneous Vascular Resistance

1. Laser Doppler flowmetry has been used to study changes in cutaneous erythrocyte flux produced in the hand (i) on successive immersion of the contralateral hand in water at 20°C (cold test) and then in water at 0–4°C (cold pressor test), and (ii) by mental arithmetic. 2. In 11 subjects, placing the right hand in water at 20°C for 2 min induced a significant decrease in cutaneous erythrocyte flux in the contralateral hand and a significant fall in mean arterial pressure. Cutaneous vascular resistance, calculated as arterial pressure/cutaneous erythrocyte flux, showed no significant change. Thus, the decrease in erythrocyte flux was apparently due to a fall in perfusion pressure. 3. Subsequent immersion of the right hand in water at 0–4°C for 2 min caused a significant decrease in erythrocyte flux in the contralateral hand and a significant rise in mean arterial pressure. It is concluded that the cold pressor response evoked from one hand elicited a substantial reflex vasoconstriction in the skin of the other hand; accordingly, calculated cutaneous vascular resistance increased significantly. 4. Eight subjects performed mental arithmetic for two periods of 2 min separated by a rest period of 2 min. By the end of the second minute of each period of mental arithmetic there was a significant decrease in erythrocyte flux. Mean arterial pressure increased significantly in the first period only, but calculated cutaneous vascular resistance increased in both periods, consistent with cutaneous vasoconstriction. 5. The cold pressor test and mental arithmetic are aversive stimuli that evoke the characteristic pattern of the alerting or defence response which includes splanchnic vasoconstriction and muscle vasodilatation. Previous studies on the cutaneous vascular component of this response have yielded equivocal results. The present study provides firm evidence that it includes cutaneous vasoconstriction, at least in the hand.

The Effects of Increasing Plasma Concentrations of Dexmedetomidine in Humans

2000 ◽  
Vol 93 (2) ◽  
pp. 382-394 ◽  
Author(s):  
Thomas J. Ebert ◽  
Judith E. Hall ◽  
Jill A. Barney ◽  
Toni D. Uhrich ◽  
Maelynn D. Colinco
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Pulmonary Artery ◽  
Arterial Pressure ◽  
Plasma Concentrations ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Central Venous ◽  
Pressor Test

Background This study determined the responses to increasing plasma concentrations of dexmedetomidine in humans. Methods Ten healthy men (20-27 yr) provided informed consent and were monitored (underwent electrocardiography, measured arterial, central venous [CVP] and pulmonary artery [PAP] pressures, cardiac output, oxygen saturation, end-tidal carbon dioxide [ETCO2], respiration, blood gas, and catecholamines). Hemodynamic measurements, blood sampling, and psychometric, cold pressor, and baroreflex tests were performed at rest and during sequential 40-min intravenous target infusions of dexmedetomidine (0.5, 0.8, 1.2, 2.0, 3.2, 5.0, and 8.0 ng/ml; baroreflex testing only at 0.5 and 0.8 ng/ml). Results The initial dose of dexmedetomidine decreased catecholamines 45-76% and eliminated the norepinephrine increase that was seen during the cold pressor test. Catecholamine suppression persisted in subsequent infusions. The first two doses of dexmedetomidine increased sedation 38 and 65%, and lowered mean arterial pressure by 13%, but did not change central venous pressure or pulmonary artery pressure. Subsequent higher doses increased sedation, all pressures, and calculated vascular resistance, and resulted in significant decreases in heart rate, cardiac output, and stroke volume. Recall and recognition decreased at a dose of more than 0.7 ng/ml. The pain rating and mean arterial pressure increase to cold pressor test progressively diminished as the dexmedetomidine dose increased. The baroreflex heart rate slowing as a result of phenylephrine challenge was potentiated at both doses of dexmedetomidine. Respiratory variables were minimally changed during infusions, whereas acid-base was unchanged. Conclusions Increasing concentrations of dexmedetomidine in humans resulted in progressive increases in sedation and analgesia, decreases in heart rate, cardiac output, and memory. A biphasic (low, then high) dose-response relation for mean arterial pressure, pulmonary arterial pressure, and vascular resistances, and an attenuation of the cold pressor response also were observed.

Sympathetic activation decreases medium-sized arterial compliance in humans

1994 ◽  
Vol 267 (4) ◽  
pp. H1368-H1376 ◽  
Author(s):  
P. Boutouyrie ◽  
P. Lacolley ◽  
X. Girerd ◽  
L. Beck ◽  
M. Safar ◽  
...  
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Mental Stress ◽  
Diastolic Pressure ◽  
Arterial Compliance ◽  
Stress Test ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Sympathetic Activation ◽  
Pressor Test

This study used a precise noninvasive method in normotensive humans to determine the effects of sympathetic activation on arterial compliance. A recently developed, high-resolution echo-tracking system capable of measuring systolic/diastolic variations of arterial diameter was coupled to a Finapres system and used to calculate instantaneous systolic/diastolic pressure-diameter and compliance-pressure curves for a muscular medium-sized artery, the radial artery. Two standardized tests of sympathetic system activation, a cold pressor test (2 min) and a mental stress test (2 min of mental arithmetic), were performed at an interval of 8 days in random order in nine healthy volunteers [30 +/- 9 (SD) yr]. Radial arterial parameters were recorded every 30 s for 9 min, which included 2 min of cold pressor test or mental stress test. During both tests, radial arterial mean diameter did not change despite t he increase in mean arterial pressure (P < 0.001); stroke change in diameter decreased (P < 0.01), whereas pulse pressure increased (P < 0.01). Arterial compliance, calculated for the instantaneous level of mean arterial pressure, decreased significantly (P < 0.01). Compliance (C) calculated at 100 mmHg (C100) was arbitrarily chosen as a reference point for comparing compliance among the different periods of the test. C100 decreased significant (P < 0.05) during both tests (from 2.93 +/- 1.27 to 2.04 +/- 0.94 and from 3.29 +/- 1.73 to 2.63 +/- 1.55 mm2.mmHg-1.10(-3) during mental stress and the cold pressor test, respectively). These results indicate that sympathetic activation is able to decrease radial arterial compliance in healthy subjects. The reduction in arterial compliance probably resulted from complex interactions between changes in distending blood pressure and changes in radial arterial smooth muscle tone.

scholarly journals Assessment of Cardiovascular Autonomic Functions to Predict Development of Pregnancy Induced Hypertension

1970 ◽  
Vol 6 (1) ◽  
pp. 41-45
Author(s):  
Nandini Kapoor ◽  
Rajeev Sharma ◽  
Munish Ashat ◽  
Anju Huria ◽  
Ghansham Mishra
Keyword(s):  
Blood Pressure ◽  
Pregnant Women ◽  
Early Stage ◽  
Blood Pressure Response ◽  
Isometric Exercise ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Roc Curve Analysis ◽  
Pressor Test ◽  
Dynamometer Test

Aim: This study aimed at performing autonomic function tests to predict PIH at early stage of pregnancy. Methods: 200 pregnant women between 12 to 20 weeks of gestation were selected for study. Handgrip dynamometer test (HGT) and Cold pressor test (CPT) were performed to assess sympathetic cardiovascular functions. Result: It was observed that 31 women out of 200 pregnant women developed PIH subsequently. ROC curve analysis was done to find out cut off values of high sensitivity and specificity for rise in systolic blood pressure (_SBP) and diastolic blood pressure (_DBP) during CPT and HGT. It was observed that out of 31 women who developed PIH/PE, 87.1% had _SBP _14mm Hg (cut off value) and 83.9% had _DBP _10mm Hg (cut off value) during CPT, both of which were statistically significant (p<0.001). Similarly for HGT, 31 women who developed PIH, _SBP _16 mm Hg and _DBP _14 mm Hg (cut off values) was observed in 96.8% and 83.9% women respectively (p< 0.001). Discriminant analysis showed that the reliability of both the tests in predicting PIH was very high (p<0.001). Conclusion: Thus it can be concluded from the study that heightened blood pressure response to physiological stimuli like cold and isometric exercise early in pregnancy could be used as a suitable tool to predict development of PIH. Key words: Cold pressor test, early detection, Handgrip dynamometer test, PIH DOI: http://dx.doi.org/10.3126/njog.v6i1.5251 NJOG 2011; 6(1): 41-45

scholarly journals Attenuated Cardiovascular Responses to the Cold Pressor Test in Concussed Collegiate Athletes

2020 ◽  
Vol 55 (2) ◽  
pp. 124-131 ◽  
Author(s):  
Blair D. Johnson ◽  
James R. Sackett ◽  
Zachary J. Schlader ◽  
John J. Leddy
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Cold Pressor Test ◽  
Collegiate Athletes ◽  
Cold Pressor ◽  
Cardiovascular Responses ◽  
Pressor Test ◽  
Healthy Control ◽  
Peak Increase

Context Cardiovascular responses to the cold pressor test (CPT) provide information regarding sympathetic function. Objective To determine if recently concussed collegiate athletes had blunted cardiovascular responses during the CPT. Design Cross-sectional study. Setting Laboratory. Patients or Other Participants A total of 10 symptomatic concussed collegiate athletes (5 men, 5 women; age = 20 ± 2 years) who were within 7 days of diagnosis and 10 healthy control individuals (5 men, 5 women; age = 24 ± 4 years). Intervention(s) The participants' right hands were submerged in agitated ice water for 120 seconds (CPT). Main Outcome Measure(s) Heart rate and blood pressure were continuously measured and averaged at baseline and every 30 seconds during the CPT. Results Baseline heart rate and mean arterial pressure were not different between groups. Heart rate increased throughout 90 seconds of the CPT (peak increase at 60 seconds = 16 ± 13 beats/min; P &lt; .001) in healthy control participants but remained unchanged in concussed athletes (peak increase at 60 seconds = 7 ± 10 beats/min; P = .08). We observed no differences between groups for the heart rate response (P &gt; .28). Mean arterial pressure was elevated throughout the CPT starting at 30 seconds (5 ± 7 mm Hg; P = .048) in healthy control individuals (peak increase at 120 seconds = 26 ± 9 mm Hg; P &lt; .001). Mean arterial pressure increased in concussed athletes at 90 seconds (8 ± 8 mm Hg; P = .003) and 120 seconds (12 ± 8 mm Hg; P &lt; .001). Healthy control participants had a greater increase in mean arterial pressure starting at 60 seconds (P &lt; .001) and throughout the CPT than concussed athletes (peak difference at 90 seconds = 25 ± 10 mm Hg and 8 ± 8 mm Hg, respectively; P &lt; .001). Conclusions Recently concussed athletes had blunted cardiovascular responses to the CPT, which indicated sympathetic dysfunction.

Cardiovascular responses to ice-cold showers

1964 ◽  
Vol 19 (6) ◽  
pp. 1145-1150 ◽  
Author(s):  
William R. Keatinge ◽  
Malcolm B. McIlroy ◽  
Alan Goldfien
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Cold Water ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Cardiovascular Responses ◽  
Normal Subjects ◽  
Plasma Norepinephrine ◽  
Arterial Blood ◽  
Sympathetic Nervous

A shower of ice-cold water (0@#X2013;2.5 C) over the chest caused large increases in systolic and diastolic arterial pressures, pulse pressure, and pulse rate in normal subjects. Cardiac output rose by 59 and 100% in the two subjects in whom it was measured. The changes in pressure were considerably larger than those caused by a cold pressor test or by anxiety. The changes appear to be due to sympathetic nervous reflexes to the heart and blood vessels rather than release of adrenal catecholamines, as plasma epinephrine did not increase and plasma norepinephrine rose only by 0.32 @#X00B5;g/liter. Hyperventilation and evidence of peripheral venoconstriction occurred during the showers, but neither voluntary hyperventilation nor increased venous return from a change in posture produced the changes in blood pressure seen during shower arterial blood pressure; cardiac output; catecholamines; sympathetic nervous reflexes; hyperventilation; peripheral venoconstriction Submitted on March 10, 1964

Increased blood pressure response to the cold pressor test in pregnant women developing pre-eclampsia

2000 ◽  
Vol 18 (4) ◽  
pp. 399-403 ◽  
Author(s):  
Christian Woisetschläger ◽  
Ulla Waldenhofer ◽  
Andreas Bur ◽  
Harald Herkner ◽  
Herbert Kiss ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Pregnant Women ◽  
Blood Pressure Response ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Pressure Response ◽  
Pressor Test

Sympathetic neural reactivity to stress does not increase with age in healthy humans

1994 ◽  
Vol 267 (1) ◽  
pp. H344-H353 ◽  
Author(s):  
A. V. Ng ◽  
R. Callister ◽  
D. G. Johnson ◽  
D. R. Seals
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Arterial Pressure ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Handgrip Exercise ◽  
Isometric Handgrip ◽  
Isometric Handgrip Exercise ◽  
Sympathetic Nervous ◽  
Older Subjects

Sympathetic nervous system reactivity to stress is though to increase with age in humans. We tested this hypothesis by recording postganglionic sympathetic nerve activity to skeletal muscle (MSNA) (peroneal microneurography) and by measuring plasma norepinephrine concentrations (PNE), heart rate, and arterial pressure before (prestress control) and during cognitive challenge (mental arithmetic and colored word test), thermal stress (i.e., the cold pressor test), and exhaustive isometric handgrip exercise (40% of maximum voluntary force)/postexercise ischemia in 15 older (60-74 yr, mean +/- SE = 64 +/- 1) and 15 young (19–30 yr, mean +/- SE = 25 +/- 1) healthy men and women (8 males, 7 females each). The initial prestress control level of MSNA was higher in the older subjects (P < 0.01 vs. young), but there were no significant differences for PNE, heart rate, or arterial pressure. The MSNA and PNE responses to mental stress were small and not different in the two groups. MSNA and PNE increased markedly in response to the cold pressor test and isometric handgrip exercise/post exercise ischemia in both groups. The absolute unit increases in MSNA were similar in the two groups, but the relative (percentage) increases were actually smaller in the older subjects (P < 0.05 vs. young) due to their elevated baseline levels. The stress-evoked increases in arterial pressure were similar in the groups, but the older subjects tended to demonstrate smaller increases in heart rate. In general, no gender differences were noted in either age group. These findings fail to support the long-held concept that stress-induced sympathetic nervous system stimulation becomes exaggerated with age. Thus, sympathetic neural hyperreactivity does not appear to be a fundamental property of the aging process in humans.

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