[Sympathetic block after plexus anesthesia. Comparison with stellate ganglion block]

Plethysmographic measurements of the upper extremity were performed in ten patients after axillary plexus block and in eight patients after stellate ganglion block. Axillary plexus block was followed by a mean increase of 396% in arterial blood flow. After stellate ganglion block, the arterial blood flow increased by 232% (P less than or equal to 0.001) compared to the pre-block value. There was no change in venous capacity after either method. The results indicate that both blocks can alternatively be used, as they have the same effects regarding increased arterial flow and stable venous capacity.