scholarly journals Effect of a neck compression collar on cardiorespiratory and cerebrovascular function in postural orthostatic tachycardia syndrome (POTS)

2020 ◽  
Vol 128 (4) ◽  
pp. 907-913
Author(s):  
Massimo Nardone ◽  
Juan Guzman ◽  
Paula J. Harvey ◽  
John S. Floras ◽  
Heather Edgell
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Respiratory Rate ◽  
Postural Orthostatic Tachycardia Syndrome ◽  
Brain Blood Flow ◽  
Deep Breathing ◽  
Main Effect ◽  
End Tidal ◽  
Orthostatic Symptoms ◽  
Upright Tilt

Postural orthostatic tachycardia syndrome (POTS) is accompanied by reduced brain blood flow, autonomic dysfunction, and orthostatic intolerance. We hypothesized that wearing a neck compression collar would attenuate orthostatic symptoms, increase brain blood flow, and influence autonomic reflexes. Ten participants with POTS (9 women, age: 36 ± 10) underwent two trials of supine rest, paced deep breathing (6 breaths/min), Valsalva maneuver (40 mmHg for 15 s), and 70° upright tilt. For one trial, participants wore a neck compression device (Q30 Innovations). Blood pressure, heart rate (HR), brain blood flow velocity, stroke volume, respiratory rate, and end-tidal gases were continuously measured. The Vanderbilt Orthostatic Symptom Score was compiled at the end of tilt. The use of the collar reduced the orthostatic symptom score of participants with POTS during upright tilt (26.9 ± 12.5 to 18.7 ± 13.1, P = 0.04). Collar compression in the supine condition reduced the low-frequency domain of HR variability (60 ± 18 to 51 ± 23 normalized units, P = 0.04) and increased the change in HR (15 ± 5 to 17 ± 6 bpm, P = 0.02) and E:I ratio (1.2 ± 0.1 to 1.3 ± 0.1, P = 0.01) during paced deep breathing. Throughout tilt, wearing the collar reduced respiratory rate (baseline: 13 ± 3 to 12 ± 4 breath/min; tilt: 18 ± 5 to 15 ± 5 breath/min; main effect of collar P = 0.048), end-tidal oxygen (baseline: 115 ± 5 to 112 ± 5 mmHg; tilt: 122 ± 10 to 118 ± 11 mmHg; main effect of collar P = 0.026). In participants with POTS, wearing the Q-collar reduced orthostatic symptoms, increased the HR response to deep breathing, and decreased resting ventilation. NEW & NOTEWORTHY We found that using a neck compression collar alleviated orthostatic symptoms in upright posture in participants with postural orthostatic tachycardia syndrome (POTS). This could be due to compression of the baroreceptors and subsequent changes in autonomic function. Indeed, we observed increased heart rate responsiveness to paced deep breathing and reductions of respiratory rate and end-tidal O2 (suggesting reduced ventilation). Further, wearing the collar reduced mean blood velocity in the brain during Valsalva perhaps due to higher brain blood volume.

Developmental pattern of hypercapnic and hypoxic ventilatory responses from childhood to adulthood

1994 ◽  
Vol 76 (1) ◽  
pp. 314-320 ◽  
Author(s):  
C. L. Marcus ◽  
W. B. Glomb ◽  
D. J. Basinski ◽  
S. L. Davidson ◽  
T. G. Keens
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Body Size ◽  
Respiratory Rate ◽  
Body Surface ◽  
Vital Capacity ◽  
Developmental Pattern ◽  
Ventilatory Responses ◽  
End Tidal ◽  
Arterial O2 Saturation

The developmental pattern of ventilatory responses, through childhood and puberty into adulthood, is not known. Therefore we studied hypercapnic (HCVR) and hypoxic ventilatory responses (HOVR) in 59 subjects (29 males and 30 females) 4–49 yr of age, of whom 35 were children ( < 18 yr old). There was a significant correlation between HCVR and weight (r = 0.33, P < 0.02), vital capacity (r = 0.30, P < 0.05), and body surface area (r = 0.30, P < 0.05) but not height (r = 0.22, NS). There was no correlation between HOVR and any of the correcting factors. To account for disparities in body size, volume-related results were scaled for body weight. The HCVR corrected for weight (HCVR/WT) decreased with age (r = -0.57, P < 0.001). HCVR/WT was significantly higher in children than in adults (0.056 +/- 0.024 vs. 0.032 +/- 0.015 l.kg-1 x min-1. Torr end-tidal PCO2-1, P < 0.001). The (tidal volume/inspiratory duration)/weight, respiratory rate, and heart rate responses to hypercapnia were increased in the children, and the CO2 threshold was lower (36 +/- 5 vs. 40 +/- 6 Torr, P < 0.05). Similarly, the HOVR corrected for weight (HOVR/WT) decreased with age (r = 0.34, P < 0.05), and HOVR/WT was significantly higher in children than in adults (-0.035 +/- 0.017 vs. -0.024 +/- 0.016 l.kg-1 x min-1.% arterial O2 saturation-1, P < 0.02). The respiratory rate and heart rate responses to hypoxia were increased in the children. We conclude that rebreathing HCVR and HOVR are higher during childhood than during adulthood.

scholarly journals Comparisons of the Nonlinear Relationship of Cerebral Blood Flow Response and Cerebral Vasomotor Reactivity to Carbon Dioxide under Hyperventilation between Postural Orthostatic Tachycardia Syndrome Patients and Healthy Subjects

2020 ◽  
Vol 9 (12) ◽  
pp. 4088
Author(s):  
Shyan-Lung Lin ◽  
Shoou-Jeng Yeh ◽  
Ching-Kun Chen ◽  
Yu-Liang Hsu ◽  
Chih-En Kuo ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Postural Orthostatic Tachycardia Syndrome ◽  
Significant Difference ◽  
Cerebral Vasomotor Reactivity ◽  
End Tidal ◽  
Fitting Model

Postural orthostatic tachycardia syndrome (POTS) typically occurs in youths, and early accurate POTS diagnosis is challenging. A recent hypothesis suggests that upright cognitive impairment in POTS occurs because reduced cerebral blood flow velocity (CBFV) and cerebrovascular response to carbon dioxide (CO2) are nonlinear during transient changes in end-tidal CO2 (PETCO2). This novel study aimed to reveal the interaction between cerebral autoregulation and ventilatory control in POTS patients by using tilt table and hyperventilation to alter the CO2 tension between 10 and 30 mmHg. The cerebral blood flow velocity (CBFV), partial pressure of end-tidal carbon dioxide (PETCO2), and other cardiopulmonary signals were recorded for POTS patients and two healthy groups including those aged >45 years (Healthy-Elder) and aged <45 years (Healthy-Youth) throughout the experiment. Two nonlinear regression functions, Models I and II, were applied to evaluate their CBFV-PETCO2 relationship and cerebral vasomotor reactivity (CVMR). Among the estimated parameters, the curve-fitting Model I for CBFV and CVMR responses to CO2 for POTS patients demonstrated an observable dissimilarity in CBFVmax (p = 0.011), mid-PETCO2 (p = 0.013), and PETCO2 range (p = 0.023) compared with those of Healthy-Youth and in CBFVmax (p = 0.015) and CVMRmax compared with those of Healthy-Elder. With curve-fitting Model II for POTS patients, the fit parameters of curvilinear (p = 0.036) and PETCO2 level (p = 0.033) displayed significant difference in comparison with Healthy-Youth parameters; range of change (p = 0.042), PETCO2 level, and CBFVmax also displayed a significant difference in comparison with Healthy-Elder parameters. The results of this study contribute toward developing an early accurate diagnosis of impaired CBFV responses to CO2 for POTS patients.

scholarly journals Adenosine receptor-dependent signaling is not obligatory for normobaric and hypobaric hypoxia-induced cerebral vasodilation in humans

2017 ◽  
Vol 122 (4) ◽  
pp. 795-808 ◽  
Author(s):  
Ryan L. Hoiland ◽  
Anthony R. Bain ◽  
Michael M. Tymko ◽  
Mathew G. Rieger ◽  
Connor A. Howe ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
High Altitude ◽  
Sea Level ◽  
Adenosine Receptor ◽  
Hypobaric Hypoxia ◽  
End Tidal ◽  
Double Blinded

Hypoxia increases cerebral blood flow (CBF) with the underlying signaling processes potentially including adenosine. A randomized, double-blinded, and placebo-controlled design, was implemented to determine if adenosine receptor antagonism (theophylline, 3.75 mg/Kg) would reduce the CBF response to normobaric and hypobaric hypoxia. In 12 participants the partial pressures of end-tidal oxygen ([Formula: see text]) and carbon dioxide ([Formula: see text]), ventilation (pneumotachography), blood pressure (finger photoplethysmography), heart rate (electrocardiogram), CBF (duplex ultrasound), and intracranial blood velocities (transcranial Doppler ultrasound) were measured during 5-min stages of isocapnic hypoxia at sea level (98, 90, 80, and 70% [Formula: see text]). Ventilation, [Formula: see text] and [Formula: see text], blood pressure, heart rate, and CBF were also measured upon exposure (128 ± 31 min following arrival) to high altitude (3,800 m) and 6 h following theophylline administration. At sea level, although the CBF response to hypoxia was unaltered pre- and postplacebo, it was reduced following theophylline ( P < 0.01), a finding explained by a lower [Formula: see text] ( P < 0.01). Upon mathematical correction for [Formula: see text], the CBF response to hypoxia was unaltered following theophylline. Cerebrovascular reactivity to hypoxia (i.e., response slope) was not different between trials, irrespective of [Formula: see text]. At high altitude, theophylline ( n = 6) had no effect on CBF compared with placebo ( n = 6) when end-tidal gases were comparable ( P > 0.05). We conclude that adenosine receptor-dependent signaling is not obligatory for cerebral hypoxic vasodilation in humans. NEW & NOTEWORTHY The signaling pathways that regulate human cerebral blood flow in hypoxia remain poorly understood. Using a randomized, double-blinded, and placebo-controlled study design, we determined that adenosine receptor-dependent signaling is not obligatory for the regulation of human cerebral blood flow at sea level; these findings also extend to high altitude.

scholarly journals Assessment of Functional Hemispheric Asymmetry by Bilateral Simultaneous Cerebral Blood Flow Velocity Monitoring

1997 ◽  
Vol 17 (5) ◽  
pp. 577-585 ◽  
Author(s):  
Jürgen Klingelhöfer ◽  
Gernot Matzander ◽  
Dirk Sander ◽  
Jens Schwarze ◽  
Henning Boecker ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Flow Velocity ◽  
Transcranial Doppler ◽  
Spatial Task ◽  
Hemispheric Dominance ◽  
Left And Right ◽  
End Tidal ◽  
Overt Speech

The aim of this study was to investigate side-to-side differences of simultaneously measured middle cerebral artery (MCA) blood flow velocities during various hemisphere-specific tasks. Using a transcranial Doppler device, flow velocity changes of 24 healthy, right-handed subjects were monitored simultaneously in the left and right MCA during different hemisphere-specific tasks. Mean flow velocity (MFV) curves were averaged for each individual subject and task. Simultaneously, heart rate, blood pressure and end-tidal carbon dioxide (CO2) were measured in a subgroup of six subjects. When compared with the resting state, all stimuli produced significant ( p < 0.001) bilateral MFV increases, ranging from 2.5–9.2%. A lateralization of MFV increases with a significantly ( p < 0.001) more pronounced increase in MFV in the hemisphere contralateral to the performing hand was observed both during simple sequential finger movements and a complex spatial task. During the complex spatial task, consistently higher MFV increases were observed in the right MCA ( p < 0.001), regardless of the side of task performance. Recognition of pictorial material presented as part of a memory task, also resulted in a side-to-side difference of respective MFV increases (right > left, p < 0.001), whereas memorization did not. Whereas bilateral MFV elevations observed during stimulation with white noise were only discrete and not lateralized, exposure to overt speech produced significantly higher ( p < 0.001) MFV increases in the left MCA. The time course of the MFV reaction showed a rapid increase with an initial maximum after 4–5 s. Heart rate, blood pressure, and end-tidal CO2 showed only subtle changes during the stimulation periods. In conclusion, the observed side-to-side differences of MFV reaction in the left and right MCA concur with current functional imaging data. Bilateral simultaneous repetitive transcranial Doppler monitoring is a sensitive method to detect cerebral perfusion asymmetries caused by hemisphere-specific activation, and thus may be helpful for noninvasive assessment of hemispheric dominance for language.

scholarly journals Postural hypocapnic hyperventilation is associated with enhanced peripheral vasoconstriction in postural tachycardia syndrome with normal supine blood flow

2006 ◽  
Vol 291 (2) ◽  
pp. H904-H913 ◽  
Author(s):  
Julian M. Stewart ◽  
Marvin S. Medow ◽  
Neil S. Cherniack ◽  
Benjamin H. Natelson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Blood Volume ◽  
Peripheral Resistance ◽  
Impedance Plethysmography ◽  
Postural Tachycardia Syndrome ◽  
Peripheral Vasoconstriction ◽  
Postural Tachycardia ◽  
End Tidal

Previous investigations have demonstrated a subset of postural tachycardia syndrome (POTS) patients characterized by normal peripheral resistance and blood volume while supine but thoracic hypovolemia and splanchnic blood pooling while upright secondary to splanchnic hyperemia. Such “normal-flow” POTS patients often demonstrate hypocapnia during orthostatic stress. We studied 20 POTS patients (14–23 yr of age) and compared them with 10 comparably aged healthy volunteers. We measured changes in heart rate, blood pressure, heart rate and blood pressure variability, arm and leg strain-gauge occlusion plethysmography, respiratory impedance plethysmography calibrated against pneumotachography, end-tidal partial pressure of carbon dioxide (PetCO2), and impedance plethysmographic indexes of blood volume and blood flow within the thoracic, splanchnic, pelvic (upper leg), and lower leg regional circulations while supine and during upright tilt to 70°. Ten POTS patients demonstrated significant hyperventilation and hypocapnia (POTSHC) while 10 were normocapnic with minimal increase in postural ventilation, comparable to control. While relative splanchnic hypervolemia and hyperemia occurred in both POTS groups compared with controls, marked enhancement in peripheral vasoconstriction occurred only in POTSHC and was related to thoracic blood flow. Variability indexes suggested enhanced sympathetic activation in POTSHC compared with other subjects. The data suggest enhanced cardiac and peripheral sympathetic excitation in POTSHC.

Acute and chronic head-down tail suspension diminishes cerebral perfusion in rats

2002 ◽  
Vol 282 (1) ◽  
pp. H328-H334 ◽  
Author(s):  
M. Keith Wilkerson ◽  
Patrick N. Colleran ◽  
Michael D. Delp
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Brain Regions ◽  
Brain Blood Flow ◽  
Tail Suspension ◽  
Resistance Arteries ◽  
Total Brain ◽  
Regional Blood Flows

10.1152/ajpheart.00727.2001.—The purpose of this study was to test the hypothesis that regional brain blood flow and vascular resistance are altered by acute and chronic head-down tail suspension (HDT). Regional cerebral blood flow, arterial pressure, heart rate, and vascular resistance were measured in a group of control rats during normal standing and following 10 min of HDT and in two other groups of rats after 7 and 28 days of HDT. Heart rate was not different among conditions, whereas mean arterial pressure was elevated at 10 min of HDT relative to the other conditions. Total brain blood flow was reduced from that during standing by 48, 24, and 27% following 10 min and 7 and 28 days of HDT, respectively. Regional blood flows to all cerebral tissues and the eyes were reduced with 10 min of HDT and remained lower in the eye, olfactory bulbs, left and right cerebrum, thalamic region, and the midbrain with 7 and 28 days of HDT. Total brain vascular resistance was 116, 44, and 38% greater following 10 min and 7 and 28 days of HDT, respectively, relative to that during control standing. Vascular resistance was elevated in all cerebral regions with 10 min of HDT and remained higher than control levels in most brain regions. These results demonstrate that HDT results in chronic elevations in total and regional cerebral vascular resistance, and this may be the underlying stimulus for the HDT-induced smooth muscle hypertrophy of cerebral resistance arteries.

Comparison of effects of exercise and hyperventilation on leukocyte kinetics in humans

1993 ◽  
Vol 75 (6) ◽  
pp. 2425-2428 ◽  
Author(s):  
M. S. Fairbarn ◽  
S. P. Blackie ◽  
R. L. Pardy ◽  
J. C. Hogg
Keyword(s):  
Heart Rate ◽  
Respiratory Rate ◽  
Minute Ventilation ◽  
Mechanical Effect ◽  
Blood Samples ◽  
Healthy Men ◽  
Wbc Count ◽  
End Tidal ◽  
Isocapnic Hyperpnea ◽  
End Tidal Co2

The circulating leukocyte (WBC) count increases with exercise, because WBCs enter the circulation from the marginated pool. The lung is a major source of the demarginating cells, but it is unclear whether this occurs because of increased ventilatory movements, increased cardiac output, or both. The present study examined the mechanical effect of ventilation (VE) in six healthy men with three different protocols on three separate occasions. First, the subjects cycled for 5-min intervals at 50, 100, 150, and 200 W, and we measured heart rate (HR), minute ventilation (VE), tidal volume (VT), respiratory rate, and end-tidal CO2. Second, each subject reproduced his exercise VE by matching VT, respiratory rate, and end-tidal CO2 on a circuit designed for isocapnic hyperpnea (matched VE). The subjects then performed a hyperventilation (hyper-VE) protocol with a minimum VT of 1.5 liters and a respiratory rate of 20 breaths/min. Blood samples were drawn at rest and throughout each protocol for measurement of WBCs, hematocrit, and band cells. During cycling, VE increased (9 +/- 1 to 66 +/- 7 l/min), HR increased (71 +/- 7 to 172 +/- 10 beats/min), and WBCs increased (5.5 +/- 0.9 to 7.8 +/- 1.3 x 10(9)/l). During matched VE, VE increased (11 +/- 2 to 69 +/- 11 l/min), but neither HR nor WBCs increased (67 +/- 13 to 78 +/- 12 beats/min and 5.3 +/- 1.6 to 5.7 +/- 1.5 x 10(9)/l, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Higher postural heart rate increments on head-up tilt correlate with younger age but not orthostatic symptoms

2013 ◽  
Vol 115 (4) ◽  
pp. 525-528 ◽  
Author(s):  
Colleen T. Ives ◽  
Kurt Kimpinski
Keyword(s):  
Heart Rate ◽  
Healthy Subjects ◽  
Orthostatic Intolerance ◽  
Significant Negative Correlation ◽  
Postural Orthostatic Tachycardia Syndrome ◽  
Age Group ◽  
Younger Age ◽  
Significant Difference ◽  
Head Up Tilt ◽  
Orthostatic Symptoms

Reports have shown that younger individuals present with higher postural heart rate increments on head-up tilt (HUT). However, a correlation between the degree of heart rate increment and symptoms of orthostatic intolerance has not been determined. The objective of this study was to determine whether higher postural heart rate increments during HUT correlate with symptoms of orthostatic intolerance in healthy subjects. Postural heart rate increment on HUT did not differ between men and women ( P = 0.48) but did show a significant decrease by age group ( P < 0.0001). There was a significant negative correlation between heart rate increment on HUT and age [ r = −0.63 (−0.73, −0.51), r2 = 0.400; P < 0.0001]. There was a significant difference with respect to symptoms of orthostatic intolerance by sex ( P = 0.03) but not age ( P = 0.58). There was no significant correlation between either symptoms of orthostatic intolerance and age [ r = −0.13 (−0.31, 0.06), r2 = 0.017; P = 0.17] or heart rate increment on HUT and symptoms of orthostatic intolerance [ r = 0.15 (−0.04, 0.33), r2 = 0.022; P = 0.13]. The results demonstrate that higher postural heart rate increments in younger individuals do not result in an increase in orthostatic intolerance. This highlights the potential need for a reevaluation of the diagnostic criteria for postural orthostatic tachycardia syndrome in younger individuals.

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