[Comparison of epidural versus intravenous administration of fentanyl during epidural block]

Effects of epidural anesthesia induced with bupivacaine alone (group C), bupivacaine and fentanyl (group E), or bupivacaine and intravenous fentanyl (group I) on the onset and spread of cold sensory block, the onset of analgesia and the degree of motor block were compared. Seventy-five patients undergoing lower limb or abdominal surgery were allocated to three groups of 25; patients of group C received 15 ml of 0.5% bupivacaine and 2 ml of 0.9% saline epidurally, patients of group E received 15 ml of 0.5% bupivacaine and 2 ml of fentanyl epidurally, and patients of group I received 2 ml of fentanyl intravenously and 15 ml of 0.5% bupivacaine and 2ml of 0.9% saline epidurally. The onset time of cold sensory block at T11 was significantly shorter in groups E (6.8 +/- 1.9 (SD) min) and I (7.3 +/- 1.7 min) than in group C (9.3 +/- 1.9 min). The onset time of analgesia was also significantly shorter in groups E and I than in group C. The segmental spread of cold sensory block at 20 min after initial injection was significantly larger in groups E and I than in group C. There was no significant difference in motor block at 20 min among the three groups. Respiratory depression appeared more frequently in group I than in groups C and E. These results suggest that epidural administration of fentanyl offers a clinical advantage over intravenous administration for analgesia during epidural block.