Comparison of nalbuphine versus magnesium sulfate as an adjuvant to intrathecal hyperbaric bupivacaine (0.5%) in infraumbilical surgeries

Background
Spinal anesthesia with bupivacaine is very common for infraumbilical surgeries. Various adjuvants are added to it to improve the quality of the block and post-operative analgesia. The study period for this study was from October 2017 to March 2018, and it was a randomized double-blinded prospective observational study. In this study, we aim to compare nalbuphine and MgSO4 (magnesium sulfate) as adjuvant to hyperbaric bupivacaine in terms of sensorimotor blockage characteristics, hemodynamic stability, and postoperative analgesia. Ninety patients of ASA grades I and II, between 18 and 60 years of age of either sex posted for elective infraumbilical surgeries, after approval from the institutional review board and written informed consent, were allocated into 3 groups of 30 patients each. With the help of the randomization table, random numbers were generated, and the randomization was done at the time of giving intrathecal anesthesia.
Results
The onset of sensory and motor blockade was earlier in the nalbuphine group as compared with the other two groups. It was also observed that the duration of postoperative analgesia was longer in the patients who received magnesium sulfate as compared with the patients in the other two groups. Adverse effects (pruritus, nausea, vomiting) were more in the nalbuphine group as compared with the other two groups.
Conclusions
In a nutshell, preservative-free intrathecal 1 mg nalbuphine and 100 mg magnesium sulfate both are good adjuvants to hyperbaric bupivacaine. Nalbuphine provides faster sensory and motor onset than magnesium sulfate, whereas magnesium sulfate provides prolonged postoperative analgesia than nalbuphine.