Background: The sympathetic nervous system plays an important role in the arousal response.
Recently, the stellate ganglion block (SGB) was found to effectively treat anxiety and night
awakening in humans and decrease electroencephalogram (EEG) indices of arousal responses in
rat. But, the role of the sympathetic block in human arousal responses has not yet been studied.
Objective: We performed this prospective, double-blinded, controlled volunteer study to
investigate the sedative effects and bispectral index (BIS) changes of SGB.
Study Design: A randomized, double-blind trial.
Setting: Single academic medical center.
Methods: This study was approved by the Ethics Committee of Kyungpook National University
Hospital (ref: KNUH_10-1081) and registered with CRiS (Clinical Research Information Service,
http://cris.cdc.go.kr, ref: KCT0000036, 2010. 9.24). Twenty healthy volunteers were enrolled in
this study. The volunteers were randomly assigned to one of 2 groups: the SGB group (n = 10) and
the sham group (n =10). Volunteers in SGB group received SGB and volunteers in the sham group
received a sham procedure. BIS value, heart rate, and blood pressure were measured before and 5,
10, 20, and 30 minutes after the procedure. Observer’s Assessment of Alertness/Sedation (OAA/S)
scores were assessed before and 10 and 30 minutes after the intervention.
Results: In the SGB group, BIS values and OAA/S scores significantly decreased after the
intervention as compared to baseline (P < 0.05). The values were also significantly decreased in the
SGB group when compared to the values in sham group after the intervention (P < 0.05). There
was a significant change of mean blood pressure 10 to 30 minutes after SGB (P < 0.05). There were
no differences in heart rate during study period between groups.
Limitations: This study is limited by a relatively small sample size.
Conclusions: This study showed that SGB has a sedative effect in normal healthy volunteers, as
evidenced by decreased OAA/S scores and BIS values.
Key words: Stellate ganglion, sympathetic block, sedation, bisepctral index, EEG, volunteers
Efficacy of Sympathetic Radiofrequency in CRPS 1 Satellite Ganglion Block VS T2-T3 Sympathetic Block
