Article

OBJECTIVES: To determine the effects of 1.0 mg/kg nitro-L-arginine methyl ester
(L-NAME) on orthostatic mean arterial pressure (MAP), serum aldosterone, and
plasma renin concentrations in persons with chronic tetraplegia compared with
nonspinal cord-injured controls. DESIGN: Prospective placebo-controlled
intervention study. SETTING: James J. Peters Veterans Affairs Medical Center.
PARTICIPANTS: Patients (n=5) with tetraplegia and controls (n=7) participated.
The groups were matched for age, height, and weight; the average duration of
injury in the tetraplegia group was 22+/-14 years. INTERVENTION: Subjects with
tetraplegia visited the laboratory twice, receiving placebo on day 1 and L-NAME
(1.0 mg/kg) on day 2. The agents were infused via an intravenous catheter over 60
minutes with the patient in the supine position. Data were collected during the
infusion and then during head-up tilt to 45 degrees for 30 minutes. Control
subjects visited the laboratory once for placebo infusion and the head-up tilt
maneuver. MAIN OUTCOME MEASURE: Orthostatic MAP. RESULTS: Orthostatic MAP was
reduced after placebo infusion in subjects with tetraplegia compared with
controls (69+/-11 vs 89+/-9 mmHg, respectively; P<.01) and compared with L-NAME
infusion (90+/-16 mmHg; P<.01). Orthostatic MAP did not differ when comparing the
tetraplegia group with controls after L-NAME infusion. Orthostatic aldosterone
levels were increased after placebo compared with L-NAME infusion in persons with
tetraplegia; plasma renin levels did not differ among the groups. CONCLUSIONS:
These data suggest that nitric oxide synthase inhibition may have clinical
potential for treatment of orthostatic hypotension in persons with chronic
tetraplegia.

Langue : ANGLAIS