Functional electrical stimulation effect on orthostatic hypotension after spinal cord injury

OBJECTIVE: To investigate the possibility of using functional electrical stimulation (FES) to control orthostatic hypotension in patients with spinal cord injury (SCI) and to clarify the mechanism of the response. DESIGN: Subjects were tilted by 10 degree increments with varying intensities of lower-extremity FES. Stimulation over muscles was compared to stimulation over noncontractile sites. SETTING: Physical therapy department of a major rehabilitation center. PATIENTS: Six patients with SCI above T6 (3 with recent injury recruited consecutively from an inpatient spinal cord rehabilitation unit, and 3 from the community with longstanding injury, recruited as volunteers). MAIN OUTCOME MEASURES: Blood pressure, heart rate, and perceived presyncope score recorded at each tilt angle and analyzed using a multivariate analysis of variance statistical methodology. RESULTS: Systolic and diastolic blood pressure increased with increasing stimulation intensities (systolic, p = .001; diastolic, p = .0019) and decreased with increasing angle of tilt (p < .001) regardless of the site of stimulation. Subjects tolerated higher angles of incline with electrical stimulation than without (p = .03). CONCLUSIONS: FES causes a dose-dependent increase in blood pressure independent of stimulation site that may be useful in treating orthostatic hypotension.