Figure 2. Hemodynamic responses to intrathecal injection of bupivacaine at the lumbar spine level. Saline (10 micro liter) or bupivacaine (10 micro liter, 0.75%) was administered intrathecally in a crossover design. Only positive SDs are displayed for the bupivacaine group; only negative SDs are displayed for the saline group. There was no difference between the two groups as detected by Wilcoxon's matched-pairs signed rank test (P > 0.1).