SYMPATHETIC BLOCKADE AFTER STELLATE GANGLION BLOCK : A CONTINUOUS RECORDING USING SKIN POTENTIAL ACTIVITY

Skin potential activities (SPA) were used to assess the degree of sympathetic blockade after stellate ganglion block (SGB). The SPA were recorded bilaterally from the palmar thenar eminences in four outpatients before and after SGB. Before the SGB, the skin potential responses (SPR) on both sides were synchronous and their amplitudes were almost the same. After SGB, the SPR amplitude on the blocked side gradually fell from 1-2 minutes. Before SGB, the skin potential levels (SPL) on both sides were parallel and the lateral difference was constant. About 1-2 minutes after SGB, the SPL on the blocked side began to fall and then reached a stationary level 5 minutes after SGB. SPA variations due to factors other than peripheral blockade can be cancelled by bilateral recording. Thus, the net SPL decrease on the blocked side compared with that on the non-blocked side was proved to be a useful index for continuous, quantitative monitoring of the sympathetic blockade by the SGB