Effect of glucose concentration on the intrathecal spread of 0.5% bupivacaine

We have studied the effects of intrathecal injection of 0.5% bupivacaine in solutions containing different concentrations of glucose (0.33%, 0.83% and 8%) in three groups of 10 patients. The mean maximum extent of sensory block was significantly higher with 8% glucose (T3.6) than with 0.83% glucose (T7.2) or 0.33% glucose (T9.5). Administration of solutions containing 0.33% glucose produced a greater variability in upper level of sensory block (11 dermatomes) than the two other concentrations (six dermatomes each). The rate of onset of sensory block to T12 was fastest with solutions containing 8% glucose. Complete motor block of the legs was produced in every patient.