Reinforcement of subarachnoid block by epidural volume effect in lower abdominal surgery: A comparison between fentanyl and tramadol for efficacy and block properties

BACKGROUND: Epidural volume extension (EVE) is claimed to increase the block height and decrease the dose requirement for intrathecal drug. However, almost all studies have been done in obstetric population and none actually compares the effect of additional drugs added to epidural volume. MATERIALS AND METHODS: Seventy-five (ASA I and II) patients scheduled for lower abdominal surgery were randomly divided into three groups. All groups received intrathecal 10 mg bupivacaine; two groups received additional 10 ml of normal saline epidurally with 25 mg tramadol or 25 mg of fentanyl. Groups were than compared for maximal block height, rate of sensory block regression to T10, and motor block regression to Bromage scale of 0. Time to first analgesia and adverse effects were also compared among the three groups. MATERIALS AND METHODS: Seventy-five (ASA I and II) patients scheduled for lower abdominal surgery were randomly divided into three groups. All groups received intrathecal 10 mg bupivacaine; two groups received additional 10 ml of normal saline epidurally with 25 mg tramadol or 25 mg of fentanyl. Groups were than compared for maximal block height, rate of sensory block regression to T10, and motor block regression to Bromage scale of 0. Time to first analgesia and adverse effects were also compared among the three groups. RESULTS: Groups with EVE had statistically significant higher block height, with a significant faster regression that the control group. However, both fentanyl and tramadol groups were inseparable in respect to motor or sensory block regression. Fentanyl group had maximal time to first analgesia, followed by tramadol and control groups. Hemodynamic alterations were also more common in EVE groups. CONCLUSION: EVE can increase the block height significantly, but it seems to be limited only to the physical property of additional volume in epidural space and fentanyl or tramadol do not seem to differ in their ability to alter block properties.