Cardiovascular response to functional electrical stimulation and dynamic tilt table therapy to improve orthostatic tolerance.
Orthostatic hypotension is a common condition for individuals with stroke or spinal cord injury. The inability to regulate the central nervous system will result in pooling of blood in the lower extremities leading to orthostatic intolerance. This study compared the use of functional electrical stimulation (FES) and passive leg movements to improve orthostatic tolerance during head-up tilt. Four trial conditions were assessed during head-up tilt: (1) rest, (2) isometric FES of the hamstring, gastrocnemius and quadriceps muscle group, (3) passive mobilization using the Erigo dynamic tilt table; and (4) dynamic FES (combined 2 and 3). Ten healthy male subjects experienced 70 degrees head-up tilt for 15 min under each trial condition. Heart rate, blood pressure and abdominal echograms of the inferior vena cava were recorded for each trial. Passive mobilization and dynamic FES resulted in an increase in intravascular blood volume, while isometric FES only resulted in elevating heart rate. No significant differences in blood pressure were observed under each condition. We conclude that FES combined with passive stepping movements may be an effective modality to increase circulating blood volume and thereby tolerance to postural hypotension in healthy subjects.
Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Road, Room 407, Toronto, Ontario, Canada M5S 3G9.
Lorne
L
Chi
Kei
K
Masani
Masae
M
Miyatani
T
T
Adam Thrasher
K
K
Wayne Johnston
Alexandra
A
Mardimae
Cathie
C
Kessler
Joseph A
JA
Fisher
Milos R
MR
Popovic
D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D002319:Cardiovascular System; D004599:Electric Stimulation Therapy; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007024:Hypotension, Orthostatic / Q000628:therapy*; D008297:Male; D018667:Tilt-Table Test