Comparison of the onset and duration of analgesia with intrathecal hyperbaric bupivacaine and intrathecal hyperbaric bupivacaine plus midazolam for lower limb orthopaedic surgeries

Background: Various additive drugs have been added to bupivacaine to modify its onset and duration of analgesia; these include among others the use of midazolam, tramadol, morphine and fentanyl. This study, therefore, was aimed at comparing the onset and duration of analgesia during intrathecal hyperbaric bupivacaine 0.5% alone and intrathecal hyperbaric bupivacaine 0.5% with midazolam for lower limb orthopaedic surgeries. Methodology: This was a prospective randomized double-blinded controlled study that recruited one hundred and thirty-eight (138) ASA I and II patients scheduled for elective lower limb orthopaedic surgeries. The patients were allocated into two groups. Group BA (n=69) received 12.5mg(2.5mls) of 0.5% hyperbaric bupivacaine with 0.5mls normal saline intrathecally at L3-L4 or L4-L5 inter-space, and group BM that received 12.5mg (2.5mls) of 0.5% hyperbaric bupivacaine with 2.5mg (0.5mls) of preservatives-free midazolam at L3-L4 or L4-L5 intrathecally, no premedicants were given. Standard monitoring of the vital signs was done. The onset and duration of analgesia were documented and analysed. Results: Results showed that the mean onset time of analgesia was 37.04±4.53min and 25.65±4.84min in groups BA and BM respectively, with statistically significant difference (P < 0.01). While the mean duration of analgesia were151.43 ± 58.84 min and 323.4 ± 22.55 min in groups BA and BM respectively, P