NCT00237770

Prevention of Low Blood Pressure in Persons With Tetraplegia

• Status: Completed
• Phase: Phase 2 / Phase 3
• Study type: Interventional
• Enrollment: 16 (actual)
• Sponsor: US Department of Veterans Affairs · Federal
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Accepted

Summary

The aim of this investigation is to determine the blood pressure response to NOS inhibition, with L-NAME, in persons with tetraplegia compared to non-SCI control subjects and to establish if blood pressure can be increased while upright in those with tetraplegia. If blood pressure is increased with NOS inhibition in persons with tetraplegia, this would improve our treatment of the condition of low blood pressure during seated postures in individuals with tetraplegia.

Detailed description

Despite disruption of central command of the vasculature during orthostatic maneuvers, individuals with tetraplegia are generally able to be seated in an upright position for long periods of time without developing symptoms of orthostatic intolerance. It must be appreciated however, that orthostatic hypotension may occur unpredictably in persons with chronic tetraplegia. This may result in a range of symptoms due to cerebral hypoperfusion from mild reduction in mental acuity to loss of consciousness. Nitric oxide (NO) is the most potent endogenous vasodilator which is synthesized by the enzyme NO synthase (NOS) and may be largely responsible for orthostatic hypotension in individuals with immobilizing conditions. Recent evidence suggests an up-regulation of inducible nitric oxide synthases (NOS) activity with prolonged exposure to hind limb suspension. The effects of NOS inhibition during orthostasis on blood pressure regulation in those with chronic tetraplegia may provide insight into effective pharmacological therapy to reduce or prevent pathologic orthostatic changes. Treatment with a NOS inhibitor may facilitate the process of mobilization in those with acute higher cord lesions.

Conditions

• Hypotension
• Spinal Cord Injury

Interventions

Type	Name	Description
DRUG	N-Nitro L-arginine-methylester (L-NAME)	A non-specific inhibitor of the nitric oxide synthase enzyme.
PROCEDURE	Head-up Tilt maneuver	Participant will be placed onto tilt table and brought to 15 degrees of head up tilt for 60 minutes (intravenous infusion time). After this time, a progressive increase to 45 degrees will be completed with a 10 degree increase every 5 minutes. Participant will remain at 45 degrees for 45 minutes or until symptom onset.

Timeline

• Start date: 2003-06-01
• Primary completion: 2010-06-01
• Completion: 2010-06-01
• First posted: 2005-10-12
• Last updated: 2014-05-19
• Results posted: 2014-05-19

Locations

1 site across 1 country: United States