Effects of head-up tilting on baroreceptor control in subjects with different tolerances to orthostatic stress

2002 ◽  
Vol 103 (3) ◽  
pp. 221-226 ◽  
Author(s):  
V.L. COOPER ◽  
R. HAINSWORTH
Keyword(s):  
Blood Pressure ◽  
Vascular Resistance ◽  
Stress Test ◽  
Orthostatic Stress ◽  
Orthostatic Tolerance ◽  
Arterial Blood ◽  
Carotid Baroreceptor ◽  
Head Up Tilt ◽  
Orthostatic Stress Test ◽  
Neck Pressure

During orthostatic stress, an increase in peripheral vascular resistance normally results in arterial blood pressure being well maintained, despite a decrease in cardiac output. The present study was undertaken to determine whether the sensitivity of the carotid baroreceptor reflex was increased during orthostatic stress and whether failure to develop this increase was associated with poor orthostatic tolerance. Three groups of subjects were studied: asymptomatic controls; patients investigated for suspected posturally related syncope but who had normal responses to an orthostatic stress test (normal patients); and patients who were shown to have low orthostatic tolerance (early fainters). We determined responses of R–R interval and forearm vascular resistance (mean arterial pressure/brachial artery velocity by Doppler ultrasonography) to the loading and unloading of carotid baroreceptors by application of pressures of -30 and +30mmHg to a chamber fitted over the neck. Responses were determined after 20min of supine rest and after 10min of head-up tilt at 60°. Responses of cardiac interval were not significantly different between the three groups, and they were not altered by the postural change. Vascular responses also did not differ between the groups during supine rest. However, in healthy volunteers and in normal patients, responses to both neck suction and pressure were significantly enhanced during head-up tilt. In controls, responses to suction were increased by tilt from 0.04±0.1 to -1.01±0.2%·mmHg-1 (means±S.E.M.; P<0.001) and those to neck pressure from -0.6±0.3 to -3.1±1.1%·mmHg-1 (P<0.05). In the normal patients, the corresponding changes were: during suction, from -0.2±0.1 to -0.7±0.1%·mmHg-1 (P<0.05); during pressure, from -0.7±0.1 to -1.5±0.3%·mmHg-1 (P<0.05). In contrast, in patients with low orthostatic tolerance, posture had no effect on the reflex (neck suction, from -0.3±0.1 to -0.3±0.1%·mmHg-1; neck pressure, from -1.0±0.3 to -0.9±0.2%·mmHg-1). We suggest that an increase in the sensitivity of the carotid baroreceptor/vascular resistance reflex may be important in the maintenance of blood pressure during orthostatic stress, and that failure of this to occur in patients with posturally related syncope may go some way towards explaining their poor orthostatic tolerance.

Heterogeneity of responses to orthostatic stress in homozygous twins

2007 ◽  
Vol 102 (1) ◽  
pp. 249-254 ◽  
Author(s):  
D. D. O'Leary ◽  
R. L. Hughson ◽  
J. K. Shoemaker ◽  
D. K. Greaves ◽  
D. E. Watenpaugh ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Environmental Factors ◽  
Cardiovascular Regulation ◽  
Identical Twins ◽  
Orthostatic Stress ◽  
Orthostatic Tolerance ◽  
Arterial Blood ◽  
Head Up Tilt

Early analysis into the role of genetics on cardiovascular regulation has been accomplished by comparing blood pressure and heart rate in homozygous twins during unstressed, resting physiological conditions. However, many variables, including cognitive and environmental factors, contribute to the regulation of cardiovascular hemodynamics. Therefore, the purpose of this study was to determine the hemodynamic response of identical twins to an orthostatic stress, ranging from supine rest to presyncope. Heart rate, arterial blood pressure, middle cerebral artery blood velocity, an index of cerebrovascular resistance, cardiac output, total peripheral resistance, and end-tidal carbon dioxide were measured in 16 healthy monozygotic twin pairs. Five minutes of supine resting baseline data were collected, followed by 5 min of 60° head-up tilt. After 5 min of head-up tilt, lower body negative pressure was applied in increments of 10 mmHg every 3 min until the onset of presyncope, at which time the subject was returned to the supine position for a 5-min recovery period. The data indicate that cardiovascular regulation under orthostatic stress demonstrates a significant degree of variance between identical twins, despite similar orthostatic tolerance. As the level of stress increases, so does the difference in the cardiovascular response within a twin pair. The elevated variance with increasing stress may be due to an increase in the role of environmental factors, as the influential role of genetics nears a functional limit. Therefore, although orthostatic tolerance times were very similar between identical twins, the mechanism involved in sustaining cardiovascular function during increasing stress was different.

Sympathoadrenal-circulatory regulation of arterial pressure during orthostatic stress in young and older men

1992 ◽  
Vol 263 (5) ◽  
pp. R1147-R1155 ◽  
Author(s):  
J. A. Taylor ◽  
G. A. Hand ◽  
D. G. Johnson ◽  
D. R. Seals
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Systemic Vascular Resistance ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Older Men ◽  
Orthostatic Stress ◽  
Plasma Norepinephrine ◽  
Lower Body ◽  
Arterial Blood

Our purpose was to test the hypothesis that human aging alters sympathoadrenal-circulatory control of arterial blood pressure during orthostasis. Plasma catecholamine and hemodynamic adjustments to two different forms of orthostatic stress, lower body suction (-10 to -50 mmHg) and standing, were determined in 14 young (26 +/- 1 yr) and 13 older (64 +/- 1) healthy, normally active men. During quiet supine rest, cardiac output tended to be lower and systemic vascular resistance higher in the older men, but no other differences were observed. On average, arterial blood pressure was well maintained during both forms of orthostasis in the two groups; the older men actually demonstrated better maintenance of pressure (P < 0.05) and a lesser incidence of orthostatic hypotension than the young men during lower body suction. Despite a blunted reflex tachycardia during orthostatic stress (P < 0.05), cardiac output tended to decrease less in the older men because of a smaller decline in stroke volume (P < 0.05, suction only), whereas the reflex increases in systemic vascular resistance were not different in the two groups. The whole forearm vasoconstrictor response tended to be attenuated in the older men during lower body suction, but was identical in the two groups with standing. Forearm skin vascular resistance was unaltered during lower body suction in both groups. Orthostasis-evoked increases in antecubital venous plasma norepinephrine concentrations were similar in the young and older men, whereas little or no increases in plasma epinephrine concentrations were observed in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Pengaruh Penusukan Tunggal Titik Akupunktur Telinga Ciao Kan terhadap Tekanan Darah dan Frekuensi Denyut Jantung

2014 ◽  
Vol 21 (2) ◽  
pp. 141
Author(s):  
Yanti Ivana Suryanto
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Systolic Blood Pressure ◽  
Stress Test ◽  
Orthostatic Stress ◽  
Test Design ◽  
Post Test ◽  
Orthostatic Stress Test

Dalam praktek klinis kedokteran gigi, seringkali pasien datang dengan tekanan darah yang tinggi meskipun ia tidak memiliki riwayat hipertensi sebelumnya. Pada kondisi ini, tingginya tekanan darah seringkali dipengaruhi oleh tingkat kecemasan pasien yang nantinya akan mempengaruhi sistem saraf otonom. Akupunktur merupakan suatu metode pengobatan dengan penusukan jarum tanpa memasukkan bahan kimia ke dalam tubuh pasien. Penelitian ini bertujuan untuk mengkaji pengaruh penusukan tunggal titik akupunktur telinga Ciao Kan terhadap tekanan darah dan frekuensi denyut jantung. Hipotesis yang diajukan adalah penusukan tunggal titik akupunktur telinga Ciao Kan menyebabkan terjadinya penurunan tekanan darah dan frekuensi denyut jantung. Penelitian ini merupakan penelitian eksperimental dengan mempergunakan rancangan penelitian pre-post test design. Subjek penelitian adalah laki-laki berusia 25–35 tahun dengan tekanan sistolik lebih atau sama dengan 130 mmHg yang memenuhi kriteria inklusi dan eksklusi. Subjek menjalani orthostatic stress test, penusukan titik akupunktur telinga Ciao Kan, pengukuran tekanan darah dan frekuensi denyut jantung. Metode statistik yang dipergunakan adalah uji t, uji korelasi Pearson, dan uji ANOVA satu jalur. Uji t dilakukan pada data yang telah ditransformasi. Tekanan sistolik turun signifikan pada subyek penelitian selama perlakuan (p<0,05) namun kemudian naik kembali. Frekuensi denyut jantung juga mengalami penurunan signifikan (p<0,05) selama perlakuan dan naik kembali. Uji korelasi Pearson dilakukan untuk melihat korelasi antara tekanan arteri rata-rata dengan frekuensi denyut jantung. Hasil uji korelasi menunjukkan adanya korelasi positif antara tekanan arteri rata-rata dan frekuensi denyut jantung (r =0,373). Uji ANOVA satu jalur menunjukkan tidak adanya perbedaan nilai tekanan sistolik, tekanan diastolik, tekanan arteri rata-rata, dan frekuensi denyut jantung antar kelompok dengan respon terhadap orthostatic stress test normal, hipertonus, maupun hipotonus (p >0,05). Dengan demikian dapat dikatakan bahwa penusukan tunggal titik akupunktur telinga Ciao Kan menyebabkan terjadinya penurunan tekanan darah dan frekuensi denyut jantung. The Effect of Single Acupuncture on Ciao Kan Ear Acupoint on Blood Pressure and Heart Rate In dental clinical practice. Patient sometime come with high blood pressure even though they have no history of hypertension. In this condition, high blood pressure could be influenced by anxiety that will have an effect on autonomic nerve system. Acupuncture is a healing method with needle puncture without giving chemical substance to patient’s body. This research aimed at evaluating the effect of a single acupuncture on Ciao Kan ear acupoint on blood pressure and heart rate. Hypothesis of this research was single acupuncture on Ciao Kan ear acupoint could decrease blood pressure and heart rate. This was a pre-post test design experiment. Subjects were men, 25 – 35 years old with systolic blood pressure equal or more than 130 mmHg who met the inclusion and exclusion criteria. Subject did orthostatic stress test, acupuncture on Ciao Kan ear acupoint, blood pressure measurement, and heart rate measurement. T test was done on the transformed data. Systolic blood pressure decreased significantly (p < 0.05) during acupuncture and then increased afterward. Heart rates also decreased significantly (p < 0.05) during acupuncture and then increased afterward. Pearson correlation test was done to see the correlation between mean arterial pressure and heart rate. The results showed a positive correlation between mean arterial pressure and heart rate (r = 0.373). One way ANOVA showed no systolic, diastolic, mean arterial pressure, and heart rate differences between groups in response to orthostatic stress test normal, hyper tone, or hypo tone (p > 0.05). It could be said that single acupuncture on Ciao Kan ear acupoint could decrease blood pressure and heart rate.

Compression Stocking Length Effects on Arterial Blood Pressure and Heart Rate Following Head-Up Tilt in Healthy Volunteers

2014 ◽  
Vol 63 (6) ◽  
pp. 435-438 ◽  
Author(s):  
Kunihiko Tanaka ◽  
Shiori Tokumiya ◽  
Yumiko Ishihara ◽  
Yumiko Kohira ◽  
Tetsuro Katafuchi
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Healthy Volunteers ◽  
Arterial Blood Pressure ◽  
Compression Stocking ◽  
Arterial Blood ◽  
Head Up Tilt ◽  
Length Effects

Forearm and finger blood flow responses to passive body tilts

1979 ◽  
Vol 46 (2) ◽  
pp. 288-292 ◽  
Author(s):  
Y. A. Mengesha ◽  
G. H. Bell
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Pulse Rate ◽  
Forearm Blood Flow ◽  
Body Tilt ◽  
Finger Blood Flow ◽  
Arterial Blood ◽  
Forearm Vascular Resistance

Ten to fifteen healthy subjects, ages 18--30 yr, were used to assess the correlation of forearm blood flow with graded passive body tilts and vascular resistance and also to discern the relative effects of body tilts on finger blood flow. In the head-up tilts forearm blood flow and arterial blood pressure fell progressively, whereas forearm vascular resistance and pulse rate increased. In the head-down tilts the forearm blood flow and the arterial blood pressure increased, whereas the forearm vascular resistance and pulse rate decreased. These changes were found to be significantly correlated with the different tilt angles and with one another. In a preliminary study it was found that infrared heating of the carpometacarpal region produced finger vasodilatation similar to the forearm vasodilatation observed by Crockford and Hellon (6). However, unlike forearm blood flow, finger blood flow showed no appreciable response to either the head-up or head-down tilts. This indicates that the sympathetic tone and the volume of blood in the finger are not appreciably altered by this test procedure at least 1 min after the body tilt is assumed.

Increased vascular resistance in paralyzed legs after spinal cord injury is reversible by training

2002 ◽  
Vol 93 (6) ◽  
pp. 1966-1972 ◽  
Author(s):  
Maria T. E. Hopman ◽  
Jan T. Groothuis ◽  
Marcel Flendrie ◽  
Karin H. L. Gerrits ◽  
Sibrand Houtman
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Arterial Blood Flow ◽  
Arterial Blood ◽  
Cord Injury

The purpose of the present study was to determine the effect of a spinal cord injury (SCI) on resting vascular resistance in paralyzed legs in humans. To accomplish this goal, we measured blood pressure and resting flow above and below the lesion (by using venous occlusion plethysmography) in 11 patients with SCI and in 10 healthy controls (C). Relative vascular resistance was calculated as mean arterial pressure in millimeters of mercury divided by the arterial blood flow in milliliters per minute per 100 milliliters of tissue. Arterial blood flow in the sympathetically deprived and paralyzed legs of SCI was significantly lower than leg blood flow in C. Because mean arterial pressure showed no differences between both groups, leg vascular resistance in SCI was significantly higher than in C. Within the SCI group, arterial blood flow was significantly higher and vascular resistance significantly lower in the arms than in the legs. To distinguish between the effect of loss of central neural control vs. deconditioning, a group of nine SCI patients was trained for 6 wk and showed a 30% increase in leg blood flow with unchanged blood pressure levels, indicating a marked reduction in vascular resistance. In conclusion, vascular resistance is increased in the paralyzed legs of individuals with SCI and is reversible by training.

Regulation of arterial blood pressure in Australian tiger snakes

1978 ◽  
Vol 75 (1) ◽  
pp. 65-79 ◽  
Author(s):  
H. B. Lillywhite ◽  
R. S. Seymour
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Complete Recovery ◽  
Pressure Control ◽  
Pressure Regulation ◽  
Body Temperatures ◽  
Heating And Cooling ◽  
Arterial Blood ◽  
Preferred Temperatures ◽  
Head Up Tilt

1. Blood pressure was measured in the dorsal aorta of restrained, unanaesthetized tiger snakes (Notechis scutatus) at different body temperatures during graded, passive tilt. Aortic blood pressure in horizontal snakes showed no significant change over a range of body temperatures between 18 and 33 degrees C (mean of measurements on 16 snakes = 42.2 +/− I.98 mmHg), while heart rate increased logarithmically (Q10 approximately 2.5). Blood pressure was stable during heating and cooling between body temperatures of 15 and 30 degrees C, but the pressure was 10--50% higher during heating than during cooling. 2. Head-up tilt usually caused a brief fall in pressure at heart level followed by partial or complete recovery and tachycardia. At the cessation of tilt, there was a characteristic overshoot of the blood pressure followed by readjustment to control (pretilt) levels. Head-down tilt typically increased pressure which then either stabilized or returned toward pretilt levels. Heart rate changes during head-down tilt were not consistent in direction or magnitude. Stabilized pressures at mid-body usually increased following head-up tilt and decreased following head-down tilt, indicating physiological adjustment to posture change. Blood pressure control was evident at body temperatures ranging from 10 to 38 degrees C, but was most effective at the higher and behaviourally preferred temperatures. 3. Propranolol lowered heart rate but did not influence pressure in horizontal snakes. During head-up tilt propranolol eliminated or reduced tachycardia and sometimes reduced the efficacy of pressure compensation for tilt. Phentolamine increased heart rate, lowered blood pressure, and eliminated pressure regulation during tilt. The results suggest that sympathetically mediated reflexes assist central blood pressure regulation in the tiger snake, with vasomotor adjustments having greater importance than changes in heart rate.

L-propionylcarnitine increases postischemic blood flow but does not affect recovery of energy charge

1991 ◽  
Vol 261 (1) ◽  
pp. H172-H180 ◽  
Author(s):  
L. M. Sassen ◽  
K. Bezstarosti ◽  
W. J. Van der Giessen ◽  
J. M. Lamers ◽  
P. D. Verdouw
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Systemic Vascular Resistance ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Contractile Function ◽  
Energy Charge ◽  
Left Ventricular ◽  
Arterial Blood

Effects of pretreatment with L-propionylcarnitine (50 mg/kg, n = 9) or saline (n = 10) were studied in open-chest anesthetized pigs, in which ischemia was induced by decreasing left anterior descending coronary artery blood flow to 20% of baseline. After 60 min of ischemia, myocardium was reperfused for 2 h. In both groups, flow reduction abolished contractile function of the affected myocardium and caused similar decreases in ATP (by 55%) and energy charge [(ATP + 0.5ADP)/(ATP + ADP + AMP); decrease from 0.91 to 0.60], mean arterial blood pressure (by 10-24%), the maximum rate of rise in left ventricular pressure (by 26-32%), and cardiac output (by 20-30%). During reperfusion, “no-reflow” was attenuated by L-propionylcarnitine, because myocardial blood flow returned to 61 and 82% of baseline in the saline- and L-propionylcarnitine-treated animals, respectively. Cardiac output of the saline-treated animals further decreased (to 52% of baseline), and systemic vascular resistance increased from 46 +/- 3 to 61 +/- 9 mmHg.min.l-1, thereby maintaining arterial blood pressure. In L-propionylcarnitine-treated pigs, cardiac output remained at 75% of baseline, and systemic vascular resistance decreased from 42 +/- 3 to 38 +/- 4 mmHg.min.l-1. In both groups, energy charge but not the ATP level of the ischemic-reperfused myocardium tended to recover, whereas the creatine phosphate level showed significantly more recovery in saline-treated animals. We conclude that L-propionylcarnitine partially preserved vascular patency in ischemic-reperfused porcine myocardium but had no immediate effect on “myocardial stunning.” Potential markers for long-term recovery were not affected by L-propionylcarnitine.

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