Blood Pressure and Brain Blood Flow Regulation After Midodrine Administration in Those With Spinal Cord Injury

Neural and Mechanical Baroreflex Sensitivity and Cerebral Blood Flow

This project aims to evaluate the physiological effects of Midodrine administration during orthostatic challenge in those with high level spinal cord injury. Midodrine has been shown to improve orthostatic symptoms in those with spinal cord injury but the physiological mechanisms influenced have not been identified. The investigators will examine key physiological components influencing orthostatic tolerance. The investigators will do this, by measuring the baroreflex, and brain blood flow autoregulation (the ability to maintain brain blood flow) before during and after the sit-up test. Two sit-up tests will occur; one before Midodrine administration, and one after administration of a 10mg dose of Midodrine.

Inclusion Criteria:

• To be included in the study, participants must have sustained a traumatic spinal cord injury within the ages of 18-49 years.
• Also, participants must have an injury level above the 6th thoracic vertebrae and be a non-smoker for a minimum of one year.

Exclusion Criteria:

• Any participants with a history of cardiovascular disease, pulmonary disease or diabetes mellitus will not be eligible.
• Also, participants will not be eligible to take part in study if they experiences acute distress, or are taking medications known to influence cardiovascular function.
• Patient will be not eligible for the study if he/she has known adverse reaction to Midodrine.