[Prolongation of hyperbaric bupivacaine spinal anesthesia with clonidine]

Recent reports showed that spinal clonidine might provide satisfactory analgesia via a nonopioid mechanism. In this study we tried to evaluate the prolongation of analgesic effect of the hyperbaric bupivacaine spinal anesthesia with clonidine. 40 ASA class I-II patients scheduled for TURP were randomly classified into two groups of 20 each. In saline group, 3 ml 0.5% hyperbaric bupivacaine plus 1 ml normal saline was given. In clonidine group, 1 ml (0.15 mg) clonidine in addition to 3 ml 0.5% bupivacaine was given. All the patients were placed in lateral position and dural puncture was made at the L3-4 interspace using a 25G spinal needle. Assessment of the sensory blockade by "pinprick" and motor blockade by Bromage scale and measurement of blood pressure and heart rate were performed after injection. All data were analyzed by Student's t-test. A p value less than 0.05 was considered statistically significant. Our results showed that the highest sensory blockade level and the time required for maximal spread of the sensory blockade were of no significant difference between groups. The mean time for two segments regression and mean time for regression to L2 were significantly greater in the clonidine group than in the saline group (p less than 0.001). Motor blockade was also prolonged in the clonidine group than the clonidine group. Side effects such as hypotension (10 in clonidine gp vs 4 in saline gp) and bradycardia (4 clonidine gp vs 2 in saline gp) commonly occurred in the clonidine group, but all patients could be effectively treated with ephedrine and atropine respectively.(ABSTRACT TRUNCATED AT 250 WORDS)