NCT00748059

The Pathophysiology of Orthostatic Hypotension

• Status: Completed
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 10 (actual)
• Sponsor: Vanderbilt University Medical Center · Academic / Other
• Sex: All
• Age: 12 Years – 70 Years
• Healthy volunteers: Not accepted

Summary

The purpose of this study is to determine the cause of low blood pressure in selective patients who have problems with their involuntary (autonomic) nervous system. These patients frequently have had symptoms throughout their life, and their disorder might have a genetic basis. The biochemical, physiological and pharmacological procedures in this study should help us define the problem and perhaps lead to more effective treatment.

Conditions

• Autonomic Nervous System Diseases
• Orthostatic Hypotension
• Dopamine Beta-Hydroxylase Deficiency
• Orthostatic Intolerance

Interventions

Type	Name	Description
PROCEDURE	Standing or upright tilt	stand upright or tilt table test
PROCEDURE	Microneurography	Recording from sympathetic nerve
PROCEDURE	QSweat	quantitative sweat testing
DEVICE	neck cuff stimulation	Blood pressure receptors in the neck arteries may be stimulated by applying suction through a collar around the neck.
DRUG	phenylephrine,isoproterenol,nitroprusside,propranolol,edrophonium,atropine,tyramine	IV Pharmacological Testing phenylephrine 12.5 - 400 ug, isoproterenol 0.1 - 0.4 ug or higher until desired effect, nitroprusside 0.1 - 1.6 ug/kg, propranolol 1.1 mg/min, edrophonium maximum of 10 mg, atropine .01 mg/kg, tyramine 250-4000 ug or higher until desired effect
DRUG	clonidine,yohimbine,metoclopramide,alpha-methyldopa	Oral Pharmacological Testing clonidine 0.1-0.3 mg, yohimbine 5-10 mg, metoclopramide 10 mg, alpha-methyldopa 62.5 mg, placebo
PROCEDURE	BodPod	Determination of body composition
PROCEDURE	Eye exam	Examination of pressure in the eye and eyelid fatiguability. The following eyedrops might be used: 1. 0.5% proparacaine (Alcaine, Allergan, Inc) 2. Fluress (0.4% benoxinate hydrochloride, fluorescein sodium, Akorn, Inc) 3. 0.5%, 1% tropicamide (Mydriacyl, Alcon) 4. Over-the-counter preservative-free artificial tears 5. 0.25%, 2.5% and 10% phenylephrine (Bausch and Lomb) 6. 1% cyclopentolate hydrochloride (Alcon)
PROCEDURE	Sleep study	Recording of sleep pattern overnight
PROCEDURE	Pain response testing	Subjects will rate the quality and intensity of 2 pain tasks.
PROCEDURE	Metabolic chamber	Determination of metabolic rate via 24hr stay in whole-room indirect calorimeter
PROCEDURE	Brain function studies	Questionnaires and computer tasks, an EEG and an MRI may be used to assess brain function.
PROCEDURE	Bicycle Exercise Test	Blood pressure and heart rate may be monitored while exercising on a stationary bicycle.

Timeline

• Start date: 1996-12-01
• Primary completion: 2020-12-01
• Completion: 2020-12-01
• First posted: 2008-09-08
• Last updated: 2021-05-12

Locations

1 site across 1 country: United States