Longitudinal Autonomic Characterization as a Predictor for Secondary Medical Complications Post-SCI

Inclusion criteria * 18-75 years old * Spinal cord injury with neurological level of injury from C6-T12 * ASIA Impairment Scale A-D. * Either acute SCI \<3 months prior (n=10) or chronic SCI (\>1 year since injury, n=8). Exclusion criteria * Symptoms of cardiovascular (including, but not limited to: hypertension, stroke, chest pain, etc.), respiratory, peripheral neurological or autonomic disease (particularly diabetes mellitus requiring treatment); * Women who are pregnant or lactating * Taking or being administered a medication known to potentially have adverse interactions with phenylephrine * In the judgement of the principal investigator, any illness or condition that will interfere with the patient's ability to comply with the protocol, compromise patient safety, or interfere with the interpretation of the study results.