English

Abstract

BACKGROUND Postoperative pain is the most challenging task in patients undergoing knee joint surgeries under spinal anaesthesia. Spinal anaesthesia with bupivacaine provides adequate intraoperative conditions but falls short in providing prolonged postoperative pain relief. Intrathecal opioids are synergistic with local anaesthetics and intensify the sensory block without affecting the sympathetic block. This study intends to compare three different doses of intrathecal nalbuphine as an adjuvant to 0.5 % hyperbaric bupivacaine and determine the optimal dose in knee joint surgeries. METHODS A double-blind comparative study was conducted in one hundred and twenty American Society of Anaesthesiologists (ASA) I and II patients undergoing knee joint surgeries in a randomised prospective way. The patients were randomly allocated to A, B, and C groups who received 0.4, 0.8 and 1.2 mg nalbuphine respectively added to 12.5 mg of 0.5 % hyperbaric bupivacaine. The onset, duration of block, duration of effective analgesia, Visual Analogue Scale (VAS) score, and the incidence of adverse effects were studied and compared between the groups. RESULTS The mean onset time of sensory and motor block of group B and C was significantly faster as compared to the onset in group A. The duration of sensory, motor blockade and duration of analgesia were highest with 1.2 mg of nalbuphine followed by 0.8 and 0.4 mg (P < 0.05). VAS readings were comparable in all the groups. Hemodynamic variability among the three groups was comparable. Incidence of adverse effects was highest in group C when compared with others, although it was statistically insignificant (P > 0.05). CONCLUSIONS Nalbuphine in a dose of 0.8 mg when added to 0.5 % hyperbaric bupivacaine for subarachnoid block in patients undergoing knee joint surgeries provides excellent analgesia, prolonged duration of sensory block and motor block, with minimal adverse effects. KEYWORDS Local Anaesthesia, Opioid, Postoperative Pain, Orthopaedic Surgeries