Comparison of nalbuphine versus fentanyl as an adjuvant to 0.75% isobaric ropivacaine in subarachnoid block for orthopedic surgery of lower limbs: A randomized, double-blind study

Background: Ropivacaine is an effective and safe alternative local anesthetic for subarachnoid block with a lesser duration of motor blockade and less neuro-cardiotoxicity. While fentanyl is commonly used as an adjuvant, nalbuphine recently got popular by its μ-attenuation and k-accentuation effects. We compared the efficacy of intrathecal fentanyl versus nalbuphine as an adjuvant to ropivacaine in subarachnoid block. Materials and Methods: In this prospective, randomized, double-blind study, seventy adult patients who were posted for elective lower limb orthopedic surgeries were randomly allocated to two groups. Group F received 22.5 mg of 0.75% isobaric ropivacaine with 25 μg fentanyl, and Group N received 22.5 mg of 0.75% isobaric ropivacaine with 1 mg nalbuphine intrathecally. Hemodynamics, onset, block duration, peak sensory level, two-segment regression time, and adverse effects such as nausea, vomiting, pruritus, sedation, hypotension, and bradycardia were studied. P