Comparative study of intrathecal preservative-free midazolam versus nalbuphine as an adjuvant to intrathecal bupivacaine (0.5%) in patients undergoing elective lower-segment caesarean section

Background: Intrathecal anesthesia is common for parturients undergoing lower-segment caesarean section. Various adjuvants are added to intrathecal bupivacaine for potentiating pharmacological effects, improving quality of sensorimotor block and postoperative analgesia, and preventing adverse effects. The study period was from November 2017 to September 2018, and it was a randomized double-blinded observational study. The sample size calculation was done according to results of our pilot study (done with 5 patients in each group) and discussion with the institutional review board. Also, in this study, we aim to assess nalbuphine/midazolam as adjuvant to intrathecal bupivacaine for LSCS in terms of quality of sensorimotor block, postoperative analgesia, adverse effects, hemodynamic stability, and Apgar scores of baby at 1 and 5 min. One hundred full-term parturients between 20 and 35 years of ASA grade I/II scheduled for elective lower-segment caesarean section after approval from the institutional review board, and written informed consent were allocated into 2 groups. Randomization was done at the time of giving intrathecal anesthesia by odd and even numbers in an opaque sealed envelope. Group A (n = 50): Bupivacaine heavy (0.5%) 2.0 ml (10 mg) + 0.2 ml Preservative-free inj. midazolam 1 mg Group B (n = 50): Bupivacaine heavy (0.5 %) 2.0 ml (10 mg) + 0.2 ml (0.75 mg) Preservative-free inj. nalbuphine The primary outcome was to assess the perioperative hemodynamic stability, Apgar score, and postoperative analgesia, and the secondary outcome was to assess the complications and adverse effects during the study period. Results: The onset of sensory and motor block was earlier in group A than in group B. Total duration of effective postoperative analgesia was more in the midazolam group as compared with the nalbuphine group. The incidence of complications (nausea, vomiting, and pruritus) were more in group B as compared with group A. Conclusion: Nalbuphine and midazolam both are good adjuvants to hyperbaric bupivacaine for LSCS in terms of hemodynamic stability and good Apgar scores at 1 and 5 min. Intrathecal midazolam provides better postoperative analgesia and less adverse effects.