Plasma concentrations of bupivacaine after stellate ganglion block using two volumes of 0.25% bupivacaine plain solution.

Plasma concentrations of bupivacaine were measured in patients after stellate ganglion block using either 10 or 20 ml of 0.25% plain solution. The mean peak concentrations were greater in the larger volume group, but this was not statistically significant. From 30 min after injection, there was a significantly greater plasma concentration in the larger volume group. The concentrations approached the limit of detection in the smaller volume group at 2 h after block.