Plasma concentrations of bupivacaine following single needle lumbar sympathectomy using two volumes of 0.25% bupivacaine plain solution.

Plasma bupivacaine concentrations were measured in 10 patients after lumbar sympathectomy using 10 ml or 20 ml of 0.25% bupivacaine plain solution. A single needle technique was employed, positioned at the L3 level. Mean peak concentrations were greater in the larger volume group and were statistically significant at 20, 30, 60, 90 and 120 min. Plasma bupivacaine levels peaked earlier in the smaller volume group. Some patients in the larger volume group still had plasma bupivacaine levels at or near peak values at 120 min. No patient approached toxic plasma levels of bupivacaine.