Stellate ganglion block (SGB) is known to increase blood flow to the innervation area of the stellate ganglion. Near infrared spectroscopy reflects changes of blood volume and allows continuous, non-invasive, and bedside monitoring of regional cerebral oxygen saturation (rSO2). Previous studies have shown the increment of the rSO2 on the block side from the baseline and the decrement of the rSO2 on the non-block side after SGB. Patients with cerebral vascular disease undergoing SGB might be at risk a decrease in cerebral blood flow in the non-block side. The investigators researched the effect of oxygen administration on rSO2 in the non-block side using a near infrared spectroscopy after SGB. 5 L/min oxygen was supplied via nasal cannula from 15 minutes after SGB. The rSO2 in the non-block side were measured before SGB and 5, 10, 15, 20, 25 and 30 minutes after SGB.

The present study suggests that oxygen administration can increase the rSO2 of non-block side. In conclusion, it is our belief that oxygen supplement is helpful to the patient with cerebral vascular disease during SGB.

Inclusion Criteria:

• ages between 20 and 70 years
• ASA PS 1,2
• disease entity : pain in the head, neck, upper extremity, and SSNHL ( sudden sensory neural hearing loss )

Exclusion Criteria:

• patient with the tendency to bleed
• patient who had cerebrovascular disease
• patient with respiratory disease ( COPD: chronic obstructive lung disease )
• patients who do not give written informed consent to participate in the study