Article

OBJECTIVE: To compare the effect of different sympathetic stimuli, that is,
exaggerated sympathetic activity and orthostatic challenges, on the increase in
leg vascular resistance in persons with spinal cord injury (SCI) without and
controls with supraspinal sympathetic control. DESIGN: Case-control intervention
study. SETTING: Physiology research laboratory. PARTICIPANTS: Persons with SCI
(N=9; motor and sensory complete spinal cord lesion above the sixth thoracic
spinal segment) and able-bodied controls (N=9). INTERVENTIONS: In persons with
SCI, exaggerated sympathetic activity was evoked by autonomic dysreflexia, and in
controls, by using a cold pressor test (CPT). A 30 degrees head-up tilt (HUT) was
performed in both groups. MAIN OUTCOME MEASURE: Leg blood flow was measured by
using venous occlusion plethysmography during the different sympathetic stimuli.
Leg vascular resistance was calculated as the arterial-venous pressure gradient
divided by blood flow. RESULTS: In persons with SCI, leg vascular resistance
significantly increased during autonomic dysreflexia and 30 degrees HUT (25+/-20
and 24+/-13 arbitrary units [AU], respectively), with no difference (P=.87)
between stimuli. In controls, leg vascular resistance significantly increased
during CPT and 30 degrees HUT (15+/-13 and 29+/-12AU, respectively) with no
difference (P=.03) between stimuli. There were no differences (P=.22) in increase
in leg vascular resistance during the different sympathetic stimuli between
persons with SCI and controls. CONCLUSIONS: The increase in leg vascular
resistance during autonomic dysreflexia in persons with SCI is not different from
that during 30 degrees HUT, which might be caused by a limited vasoconstrictor
reserve. Despite the lack of supraspinal sympathetic control in persons with SCI,
the increase in leg vascular resistance during exaggerated sympathetic activity
was not different from controls.
CI - Copyright (c) 2010 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS