Epidural Stimulation Normalizes BP of Paraplegic

A new study suggests that spinal cord epidural stimulation (scES) can elevate blood pressure in individuals with spinal cord injury (SCI) suffering from chronic hypotension.

Researchers at the University of Louisville (UofL; KY, USA) and the Frazier Rehab Institute (Louisville, KY, USA) conducted a study to test the hypothesis that cardiovascular function scES can increase resting blood pressure and attenuate chronic hypotension in individuals with chronic cervical SCI. The study included four participants who received an implant of a 16-electrode array on the dura (L1–S1 cord segments, T11–L1 vertebrae).

The individual-specific CV-scES configurations, including electrode selection, voltage, frequency, and pulse width, were identified in order to maintain systolic blood pressure within targeted normative ranges without skeletal muscle activity of the lower extremities, as assessed by electromyography (EMG). Each participant completed five two-hour sessions of cardiovascular function scES in an upright, seated position during measurement of blood pressure and heart rate. Noninvasive continuous blood pressure was measured from a finger cuff by plethysmograph.

The results showed significant increases in mean arterial pressure in response to cardiovascular function scES, which was maintained within normative ranges, and that stimulating the dorsal lumbosacral spinal cord can effectively and safely activate mechanisms to elevate blood pressures to normal ranges from a chronic hypotensive state in people with severe cervical SCI. The study was published on March 8, 2018, in Frontiers in Human Neuroscience.

“People with severe spinal cord injury -- especially when it occurs in a higher level in the spine -- have problems with blood pressure regulation to the point that it becomes the main factor affecting quality of life for them,” said senior author professor of cardiology Glenn Hirsch, MD, of UofL. “Some cannot even sit up without passing out. They are forced to use medications, compression stockings, or abdominal binders to maintain an adequate blood pressure. This intervention appears to reliably and reproducibly maintain blood pressure.”

Orthostatic hypotension, also known as postural hypotension, occurs when a person's BP suddenly falls when they stand up. Orthostatic hypotension is primarily caused by gravity-induced blood pooling in the lower extremities, which in turn compromises venous return, resulting in decreased cardiac output and subsequent lowering of arterial pressure. In is common in people suffering from SCI.

Related Links:
University of Louisville
Frazier Rehab Institute