Please use this identifier to cite or link to this item:
Title: Pressor dose responses and baroreflex sensitivity in quadriplegic spinal cord injury patients.
Austin Authors: Krum, Henry;Louis, William J ;Brown, Douglas J;Howes, L G
Affiliation: Department of Clinical Pharmacology, Austin Hospital, Heidelberg, Victoria, Australia
Issue Date: 1-Mar-1992
Publication information: Journal of Hypertension; 10(3): 245-50
Abstract: To assess the relative contribution of impaired baroreceptor reflexes and enhanced cardiovascular reactivity to the exaggerated blood pressure rises which occur in quadriplegic spinal cord injury patients with automatic hyperreflexia.Pressor dose responsiveness was evaluated by determining the steady-state dose of phenylephrine, alpha-methylnoradrenaline and angiotensin II required to achieve a blood pressure rise of 20 mmHg and the steady-state dose of isoprenaline required to increase heart rate by 20 beats/min in eight quadriplegic spinal cord injury patients and eight control subjects.The dose of phenylephrine alpha-methylnoradrenaline and angiotensin II to achieve a rise in blood pressure of 20 mmHg was significantly reduced in the spinal cord injury group, whilst the dose of isoprenaline required to raise heart rate by 20 beats/min did not differ significantly from the control group. Baroreceptor sensitivity, assessed by straight line regression of change in heart period with change in blood pressure during steady-state infusions of phenylephrine, did not differ statistically between the two groups, but the results could not exclude some evidence of impairment in the spinal cord injury patients. Baroreceptor sensitivity was much less variable in spinal cord injury patients than in controls.These findings suggest that quadriplegic patients with spinal cord injury have exaggerated pressor responses with significantly less variability in baroreflex sensitivity. The former probably contributes to the autonomic hyperreflexia seen in these patients. The latter provides some support to the suggestion that centrally mediated psychogenic responses contribute to the variability in baroreceptor sensitivity seen in normal subjects.
Gov't Doc #: 1315821
Type: Journal Article
Subjects: Adult
Angiotensin II.pharmacology
Blood Pressure.drug effects.physiology
Blood Pressure Determination.methods
Dose-Response Relationship, Drug
Heart Rate.drug effects.physiology
Pressoreceptors.drug effects.physiology
Reflex.drug effects.physiology
Regression Analysis
Spinal Cord Injuries.epidemiology.physiopathology
Appears in Collections:Journal articles

Show full item record

Page view(s)

checked on Nov 28, 2022

Google ScholarTM


Items in AHRO are protected by copyright, with all rights reserved, unless otherwise indicated.