Comparison of two doses of intrathecal nalbuphine as an adjuvant to bupivacaine in lower abdomen and lower limb surgeries

Background and aim: Our aim was to compare and evaluate the effect of addition of two doses of Nalbuphine 0.2 mg and 0.4 mg to Hyperbaric 0.5% Bupivacaine intrathecally in patients undergoing lower abdominal and lower limb surgeries.
Methods: The study was conducted on 50 patients randomly divided into two groups of 25 each belonging to ASA grade I and II, aged between 18 to 60 years of either gender, scheduled for elective lower abdomen or lower limb surgeries under spinal anaesthesia. In Group A, 0.2 mg nalbuphine diluted to 0.5 ml was added to 3 ml 0.5% hyperbaric bupivacaine to make a total volume of 3.5 ml whereas in Group B, 0.4 mg nalbuphine diluted to 0.5 ml was added to 3 ml 0.5% hyperbaric bupivacaine to make a total volume 3.5 ml. The onset of sensory and motor block, time taken for peak sensory block, two segment regression of sensory block, duration of motor and sensory block and time taken for rescue analgesia were noted. Side effects and haemodynamic changes were also noted.
Results: The demographic profile of the study subjects was comparable. Parameters observed revealed that the onset of sensory blockade was comparable in both the groups and onset of complete motor block was faster in the Nalbuphine 0.4 mg group as compared to the Nalbuphine 0.2 mg group. The total duration of sensory and motor block were significantly prolonged in the Nalbuphine 0.4 mg group. The duration of analgesia was longer in the patients who received Nalbuphine 0.4 mg. The VAS scores in the postoperative period were lower in the patients who received Nalbuphine 0.4 mg as compared with Nalbuphine 0.2 mg. Hemodynamic and respiratory parameters were stable and comparable among both groups throughout the surgery. Side effects were also comparable in the two groups.
Conclusion: We compared two doses of Nalbuphine, 0.2 mg and 0.4 mg when added intrathecally to hyperbaric 0.5% Bupivacaine for surgeries of lower abdomen and lower limb surgeries and recommend 0.4 mg nalbuphine as the preferred dose when compared to 0.2 mg as an adjuvant to 0.5 % hyperbaric bupivacaine given intrathecally with prolonged duration of sensory and motor blockade and prolonged duration of postoperative analgesia with minimal side effects.