Spinal Cord Injuries
Conditions
Brief summary
The purpose of this research is to learn about how the body is able to balance changes in blood pressure, how that changes over time, and how these changes impact a participant's risk of developing medical problems.
Interventions
DIAGNOSTIC_TESTTests of sympathetic inhibition
Bolus phenylephrine infusion using the Oxford technique will generate the need to inhibit sympathetic activity. Similarly, resting state Mayer waves will be assessed with regard to heart rate and blood pressure responses.
DIAGNOSTIC_TESTTests of above level sympathetic activation
Cold pressor test of the hand will be used to cause sympathetic activation. Valsalva's maneuver will assess the ability to buffer against blood pressure fall (phase II).
DIAGNOSTIC_TESTTesting of below level sympathetic activation
Cold pressor test of the foot and bladder pressor response will be tested.
Sponsors
Mayo Clinic
The Craig H. Neilsen Foundation
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Valsalva Maneuver Phase II | During laboratory diagnostic testing session | Presence or absence of phase II on Valsalva maneuver testing, which takes approximately 15 seconds to complete. This will be repeated x3. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Beat-to-beat heart rate | During laboratory diagnostic testing session | Electrocardiogram will record continuous measures with changes in R-R interval (ms) quantified and compared to baseline. |
| Beat-to-beat blood pressure | During laboratory diagnostic testing session | Non-invasive continuous blood pressure monitors will be used, with changes in systolic and diastolic pressure (in mmHg) from resting baseline measured. |
| Continuous galvanic skin response | During laboratory diagnostic testing session | Changes from resting state conductance with be quantified with a smartwatch. |
| Quantify autonomic dysreflexia and orthostatic hypotension | Baseline, prior to laboratory diagnostic testing session | Participants will be given the Autonomic Dysfunction Following Spinal Cord Injury questionnaire (score range 0-436, with higher scores indicating more autonomic dysfunction). |
| Respiration | During laboratory diagnostic testing session | Elastic respiratory transducer bands around mid-chest and upper abdomen will monitor breathing depth and frequency. |
| Beat-by-Beat Popliteal and Brachial Blood Flow | During laboratory diagnostic testing session | The investigators will use Doppler derived flow velocities to estimate whole limb blood flow through the popliteal and brachial arteries |
| Immunology Blood Draw | During laboratory diagnostic testing session | Baseline samples will be collected and compared against changes to blood pressure. |
| Serum Catecholamines and Cortisol | During laboratory diagnostic testing session | Baseline resting catecholamines (norepinephrine, epinephrine, dopamine) and cortisol will be drawn from the IV after 10 minutes of quiet rest at baseline and prior to bladder filling or foot cold pressor. Just prior to the conclusion of this testing, an additional blood draw will take place through the IV to assess changes in these levels. |
| Pressure-induced vasodilation | During laboratory diagnostic testing session | Changes to skin blood flow following a gradual change in pressure to the skin surface area. Laser doppler will be used to monitor changes in blood flow. |
Countries
United States
Contacts
CONTACTErin Lund
PRINCIPAL_INVESTIGATORRyan J. Solinsky, MD
Mayo Clinic
Outcome results
None listed