scholarly journals Inter-day reliability of blood pressure and cerebral blood flow velocities in persons with spinal cord injury and intact controls

2016 ◽  
Vol 40 (2) ◽  
pp. 159-169 ◽  
Author(s):  
Jill M. Wecht ◽  
Joseph P. Weir ◽  
William A. Bauman
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cord Injury ◽  
Blood Flow Velocities ◽  
Flow Velocities

scholarly journals Perturbed and spontaneous regional cerebral blood flow responses to changes in blood pressure after high-level spinal cord injury: the effect of midodrine

2014 ◽  
Vol 116 (6) ◽  
pp. 645-653 ◽  
Author(s):  
Aaron A. Phillips ◽  
Andrei V. Krassioukov ◽  
Philip N. Ainslie ◽  
Darren E. R. Warburton
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Orthostatic Intolerance ◽  
Function Analysis ◽  
Orthostatic Tolerance ◽  
Transfer Function Analysis ◽  
Cord Injury

Individuals with spinal cord injury (SCI) above the T6 spinal segment suffer from orthostatic intolerance. How cerebral blood flow (CBF) responds to orthostatic challenges in SCI is poorly understood. Furthermore, it is unclear how interventions meant to improve orthostatic tolerance in SCI influence CBF. This study aimed to examine 1) the acute regional CBF responses to rapid changes in blood pressure (BP) during orthostatic stress in individuals with SCI and able-bodied (AB) individuals; and 2) the effect of midodrine (alpha1-agonist) on orthostatic tolerance and CBF regulation in SCI. Ten individuals with SCI >T6, and 10 age- and sex-matched AB controls had beat-by-beat BP and middle and posterior cerebral artery blood velocity (MCAv, PCAv, respectively) recorded during a progressive tilt-test to quantify the acute CBF response and orthostatic tolerance. Dynamic MCAv and PCAv to BP relationships were evaluated continuously in the time domain and frequency domain (via transfer function analysis). The SCI group was tested again after administration of 10 mg midodrine to elevate BP. Coherence (i.e., linearity) was elevated in SCI between BP-MCAv and BP-PCAv by 35% and 22%, respectively, compared with AB, whereas SCI BP-PCAv gain (i.e., magnitudinal relationship) was reduced 30% compared with AB (all P < 0.05). The acute (i.e., 0–30 s after tilt) MCAv and PCAv responses were similar between groups. In individuals with SCI, midodrine led to improved PCAv responses 30–60 s following tilt (10 ± 3% vs. 4 ± 2% decline; P < 0.05), and a 59% improvement in orthostatic tolerance ( P < 0.01). The vertebrobasilar region may be particularly susceptible to hypoperfusion in SCI, leading to increased orthostatic intolerance.

Patterns of Cerebral Blood Flow and Systemic Hemodynamics During Arithmetic Processing

2008 ◽  
Vol 22 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Natalie Werner ◽  
Neval Kapan ◽  
Gustavo A. Reyes del Paso
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Time Course ◽  
Doppler Sonography ◽  
Transcranial Doppler Sonography ◽  
Systemic Hemodynamics ◽  
Heart Period ◽  
Blood Flow Velocities ◽  
Flow Velocities

The present study explored modulations in cerebral blood flow and systemic hemodynamics during the execution of a mental calculation task in 41 healthy subjects. Time course and lateralization of blood flow velocities in the medial cerebral arteries of both hemispheres were assessed using functional transcranial Doppler sonography. Indices of systemic hemodynamics were obtained using continuous blood pressure recordings. Doppler sonography revealed a biphasic left dominant rise in cerebral blood flow velocities during task execution. Systemic blood pressure increased, whereas heart period, heart period variability, and baroreflex sensitivity declined. Blood pressure and heart period proved predictive of the magnitude of the cerebral blood flow response, particularly of its initial component. Various physiological mechanisms may be assumed to be involved in cardiovascular adjustment to cognitive demands. While specific contributions of the sympathetic and parasympathetic systems may account for the observed pattern of systemic hemodynamics, flow metabolism coupling, fast neurogenic vasodilation, and cerebral autoregulation may be involved in mediating cerebral blood flow modulations. Furthermore, during conditions of high cardiovascular reactivity, systemic hemodynamic changes exert a marked influence on cerebral blood perfusion.

scholarly journals Cerebral Autoregulation during Postural Change in Patients with Cervical Spinal Cord Injury—A Carotid Duplex Ultrasonography Study

Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1321
Author(s):  
Joo-Hyun Kee ◽  
Jun-Hyeong Han ◽  
Chang-Won Moon ◽  
Kang Hee Cho
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Cerebral Autoregulation ◽  
Duplex Ultrasonography ◽  
Postural Change ◽  
Carotid Duplex ◽  
Cord Injury ◽  
Carotid Duplex Ultrasonography

Patients with a spinal cord injury (SCI) frequently experience sudden falls in blood pressure during postural change. Few studies have investigated whether the measurement of blood flow velocity within vessels can reflect brain perfusion during postural change. By performing carotid duplex ultrasonography (CDU), we investigated changes in cerebral blood flow (CBF) during postural changes in patients with a cervical SCI, determined the correlation of CBF change with presyncopal symptoms, and investigated factors affecting cerebral autoregulation. We reviewed the medical records of 100 patients with a cervical SCI who underwent CDU. The differences between the systolic blood pressure, diastolic blood pressure, and CBF volume in the supine posture and after 5 min at 50° tilt were evaluated. Presyncopal symptoms occurred when the blood flow volume of the internal carotid artery decreased by ≥21% after tilt. In the group that had orthostatic hypotension and severe CBF decrease during tilt, the body mass index and physical and functional scores were lower than in other groups, and the proportion of patients with a severe SCI was high. The higher the SCI severity and the lower the functional score, the higher the possibility of cerebral autoregulation failure. CBF should be assessed by conducting CDU in patients with a high-level SCI.

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.

scholarly journals Regional Neurovascular Coupling and Cognitive Performance in Those with Low Blood Pressure Secondary to High-Level Spinal Cord Injury: Improved by Alpha-1 Agonist Midodrine Hydrochloride

2014 ◽  
Vol 34 (5) ◽  
pp. 794-801 ◽  
Author(s):  
Aaron A Phillips ◽  
Darren ER Warburton ◽  
Philip N Ainslie ◽  
Andrei V Krassioukov
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Cognitive Function ◽  
Neurovascular Coupling ◽  
Control Group ◽  
Cord Injury ◽  
Low Blood Pressure ◽  
High Level

Individuals with high-level spinal cord injury (SCI) experience low blood pressure (BP) and cognitive impairments. Such dysfunction may be mediated in part by impaired neurovascular coupling (NVC) (i.e., cerebral blood flow responses to neurologic demand). Ten individuals with SCI > T6 spinal segment, and 10 age- and sex-matched controls were assessed for beat-by-beat BP, as well as middle and posterior cerebral artery blood flow velocity (MCAv, PCAv) in response to a NVC test. Tests were repeated in SCI after 10 mg midodrine (alpha1-agonist). Verbal fluency was measured before and after midodrine in SCI, and in the control group as an index of cognitive function. At rest, mean BP was lower in SCI (70 ± 10 versus 92 ± 14 mm Hg; P<0.05); however, PCAv conductance was higher (0.56 ± 0.13 versus 0.39 ± 0.15 cm/second/mm Hg; P<0.05). Controls exhibited a 20% increase in PCAv during cognition; however, the response in SCI was completely absent ( P<0.01). When BP was increased with midodrine, NVC was improved 70% in SCI, which was reflected by a 13% improved cognitive function ( P<0.05). Improvements in BP were related to improved cognitive function in those with SCI ( r2 = 0.52; P<0.05). Impaired NVC, secondary to low BP, may partially mediate reduced cognitive function in individuals with high-level SCI.

Cerebral Blood Flow Responses to Autonomic Dysreflexia in Humans with Spinal Cord Injury

2016 ◽  
Vol 33 (3) ◽  
pp. 315-318 ◽  
Author(s):  
Aaron A. Phillips ◽  
Philip N. Ainslie ◽  
Darren E.R. Warburton ◽  
Andrei V. Krassioukov
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Autonomic Dysreflexia ◽  
Cord Injury
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