[Regional cerebral blood flow and oxygenation following cervicothoracic sympathetic block].

Stellate ganglion block (SGB) is considered to increase blood flow to the governing area, but recent studies have shown the decrease of common carotid arterial blood flow in the unblocked side following SGB. We investigated the influence of SGB on bilateral cerebral blood flow and oxygenation using a regional oxygen saturation (rSO2) monitor, TOS-96 (TOSTEC, Japan). The changes of blood volume (hemoglobin index: Hb I) and rSO2 were measured in twenty adult patients who underwent SGB at the transverse process of the C 6 vertebra. Prior to the investigation, two sensors were calibrated and placed on either side of each patient's forehead in order to see the difference. There were significant increases in rSO2 and Hb I in the blocked side and decreases in rSO2 and Hb I in the contralateral side. These results suggest that blood flow in the blocked side following SGB increases with decreased blood flow in the unblocked side. Patients with cerebral vascular disease undergoing SGB might be at risk of a decrease in cerebral blood flow in the unblocked area.