The effect of addition of intrathecal midazolam 1.5 mg to bupivacaine in patients undergoing abdominal hysterectomy

In this prospective, randomized, double blind placebo controlled study, we investigated the postoperative analgesic efficacy of 1.5mg of intrathecal midazolam as an adjunct to bupivacaine for spinal anaesthesia in 100 patients undergoing abdominal hysterectomy. Patients were allocated randomly to 2 groups: Group B received intrathecal 3.5 ml of 0.5% heavy bupivacaine plus 0.3 ml of 0.9% saline; Group BM received 3.5 ml of 0.5% heavy bupivacaine plus 1.5 mg of preservative free midazolam (5 mg/ml). Onset of sensory analgesia, maximum level of sensory block, time to reach it, and time to two segment regression were similar between the two groups (p > 0.05). Blood pressure and heart rate were comparable between groups. The mean duration of postoperative analgesia was less in group B compared with group BM. Supplemental analgesic dose requirement with pentazocine was significantly less in Group BM compared with Group B. No neurological deficits were observed. Intraoperative sedation and oxygen desaturation was significantly higher but acceptable in Group BM.

Conclusion: Intrathecal midazolam 1.5 mg when used as an adjunct to bupivacaine provides better intraoperative sedation and moderate prolongation of postoperative analgesia.

DOI: http://dx.doi.org/10.4038/slja.v19i2.2314  

Sri Lankan Journal of Anaesthesiology Vol.19(2) 2011 pp.81-85