The Effects of Normalizing Blood Pressure on Cerebral Blood Flow in Hypotensive Individuals With Spinal Cord Injury

Summary

Participation Requirements

Description

Study 1: Subjects will visit the laboratory between 3 and 9 times for 4 hours to determine the BP response to each dose of the 3 study medications (midodrine, pyridostigmine, and mirabegron). Upon arrival to the laboratory subjects will be randomized to receive midodrine, pyridostigmine, or mirabegr...

Study 1: Subjects will visit the laboratory between 3 and 9 times for 4 hours to determine the BP response to each dose of the 3 study medications (midodrine, pyridostigmine, and mirabegron). Upon arrival to the laboratory subjects will be randomized to receive midodrine, pyridostigmine, or mirabegron. Subjects will remain seated in their wheelchair for the duration of testing. Instrumentation will be applied by study personnel while subject is seated quietly, this can take up to 20 minutes. Instrumentation includes placement of 3 ECG electrodes for continuous HR monitoring and finger and brachial BP cuffs. BP, BR and HR will be recorded for 5-minutes before medication administration (baseline). After baseline, a small pill will be given with a glass of water. BP, BR and HR will be monitored for 5-minutes every 30 minutes for 4 hours after drug administration. Study 2: Twenty will visit the laboratory on 4 occasions to determine the effects of three anti-hypotensive agents, compared to placebo, on BP, CBFv, and cognitive performance on selected neuropsychological tests. Upon arrival to the laboratory for every visit subjects will be randomized to receive midodrine, pyridostigmine, mirabegron, or matching placebo. Neither the study subject nor the investigator will know which is being administered. Subjects will remain seated in their wheelchair throughout the duration of the study session and will be closely monitored by study personnel. Instrumentation will include placement of 3 ECG electrodes for continuous heart rate (HR) monitoring, finger and brachial BP cuffs, and a Doppler ultrasound probe positioned at the left MCA for continuous CBFv monitoring. Subjects will remain quietly seated in their wheelchair for 30-minutes after instrumentation for a 5-minute recording of continuous HR, BP, and CBFv (baseline). Prior to the baseline data collection period, the first battery of cognitive tests will be administered. The study medication will be administered to the subject along with a glass of water approximately 30-minutes after arrival to the laboratory. There will be a 2 hour break period until the second cognitive battery begins.

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