Modulation of cerebral blood flow with transcutaneous electrical neurostimulation (TENS) in patients with cerebral vasospasm after subarachnoid hemorrhage.
OBJECTIVE
Transcutaneous electrical neurostimulation (TENS) and spinal cord stimulation have been shown to increase peripheral and cerebral blood flow. We postulate that certain pathological conditions attenuate cerebral autoregulation, which may result in a relative increase of the importance of neurogenic regulation of cerebral blood flow, which could be decreased by electrical modulation. We therefore assess the effects of TENS on cerebral blood flow velocities (CBFVs) and cerebral saturation in patients with cerebral vasospasm after subarachnoid hemorrhage (SAH).


METHODS
Cervical TENS was applied in 10 SAH patients with transcranial Doppler (TCD)-proven cerebral vasospasm. Measurements included plethysmography, near-infrared spectroscopy, capnography, and CBFVs by TCD. After determining the optimal frequency and current, patients were treated with cervical TENS for two periods of three days, with a pause of one day in between.


RESULTS
The TENS electrodes were not always tolerated by the patients. Higher frequencies demonstrated the most prominent combined effects. ETCO2 was 0.19% lower with TENS off than with TENS on (p = 0.05). Mean arterial blood pressure and pulse were not significantly different over time. CBFV in MCA was decreased (p = 0.07) while cerebral oxygen saturation was increased (p = 0.01) after the use of TENS.


CONCLUSIONS
Our data suggest improved cerebral blood flow when using cervical TENS in patients with cerebral vasospasm. Several factors could have attenuated the effects: the electrodes were poorly tolerated, ETCO2 increased during TENS, few vessels showed prolonged vasospasm, and overall flow velocities were low. Still, an on-off effect of TENS over time was detected.
Department of Neurosurgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Mark
M
ter Laan
J Marc C
JM
van Dijk
Roy
R
Stewart
Michiel J
MJ
Staal
Jan-Willem J
JW
Elting
D000328:Adult; D000368:Aged; D001703:Biophysics; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging; D002540:Cerebral Cortex / Q000098:blood supply* / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000628:therapy; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*; D014463:Ultrasonography; D020301:Vasospasm, Intracranial / Q000209:etiology / Q000473:pathology / Q000628:therapy; D055815:Young Adult
Cerebral blood flow; electrical stimulation; subarachnoid hemorrhage; sympathetic nervous system; vasospasm