Effects of spinal anesthesia on the electroencephalogram in the elderly.
Elderly patients frequently fall asleep during spinal anesthesia without sedatives. We investigated effects of spinal anesthesia on electroencephalogram (EEG) in elderly patients. Elderly patients were randomly assigned. Patients in Group C (n = 8) received an epidural catheter with no anesthetics as control; patients in Group S (n = 8) received spinal anesthesia. Subsequently, processed EEG data were monitored for 5 minutes. Spinal anesthesia induced significant decreases in 90% spectral edge frequency (SEF90), whereas the control group had no change in SEF90. It was concluded that spinal anesthesia induces decreased SEF90, indicating suppressed cortical activity in early phases of sensory blockade in elderly patients.
Arisaka
H
H
Department of Anesthesiology, Clinical Care Medicine, Kanagawa Dental College, 82 Inaoka-cho, Yokosuka, Kanagawa 238-8580, Japan. a-hiroumi@mpd.biglobe.ne.jp
Sakuraba
S
S
Takeda
J
J
D000368:Aged; D000369:Aged, 80 and over; D000775:Anesthesia, Spinal; D004569:Electroencephalography; D006801:Humans