Rationale: Subarachnoid block is the most preferred mode of anaesthesia for lower limb orthopaedic surgeries. To perform the subarachnoid block various local anaesthetic (LA) drugs are used like bupivacaine, ropivacaine and levobupivacaine. Bupivacaine is the most commonly used local anaesthetic agent for this purpose. Often various intrathecal adjuvants, like morphine, fentanyl, sufentanil, nalbuphine, ketamine and midazolam are added to local anaesthetics to improve the quality of subarachnoid blockand to prolong the postoperative analgesia. Addition of the adjuvants also decrease the dose of local anaesthetics requirement. Recently intrathecal levobupivacaine has been found to have a better safety profile than bupivacaine and intrathecal nalbuphine has also been tried as an adjuvant without significant adverse effects. So in the present study, we will compare the effect of addition of two different doses of nalbuphine to levobupivacaine in lower limb orthopaedic surgery under subarachnoid block. Aim: To compare the effect of addition of two different doses of nalbuphine to levobupivacaine in patients undergoing lower limb orthopaedic surgeries under subarachnoid block. Objectives: To compare the effect of addition of two different doses of nalbuphine to levobupivacaine in patients undergoing lower limb orthopaedic surgeries under subarachnoid block in terms of: Primary objective: Analgesic efficacy: Duration of effective analgesia (time from the subarachnoid block to the time of patient’s first complaint of pain with VAS ≥3) Secondary objective: 1) Quality of sensory block: -​Time of onset of sensory block (when the sensory block is achieved at level of T10 dermatome) -​Maximum block height. -​Time of two segment regression of sensory block (regression of two segments from the maximum block height achieved) 2) Quality of motor blockade: -​Modified Bromage Scale. -​Quality of muscle relaxation. -​Onset of motor blockade (time interval from intrathecal injection to the Modified Bromage Grade 1 is achieved) -​Duration of motor blockade (time interval from onset of motor block to regression of motor block to Modified Bromage Grade 0) 3) Adverse effects like nausea, vomiting, hypotension, bradycardia and pruritis etc. Setting: This study will be conducted in the Department of Anaesthesiology, Critical care and Pain Medicine, University College of Medical Sciences and GTB Hospital, Delhi after obtaining clearance from the Institutional Ethical Committee- Human Research. A written informed consent will be obtained before recruiting the patients. Study design: Double blind, randomized controlled study. Time frame: November 2018 to April 2020. Population and participants: Inclusion criteria: Patients belonging to ASA Grade I and II between the age of 18 to 65 years and height 150 to 180 cm, undergoing lower limb orthopaedic surgeries will be included in this study. Exclusion criteria: The following patients will be excluded: 1) Contraindication to subarachnoid block. 2) Known hypersensitivity to any of the drugs used in the study. 3) Obesity with BMI > 30 kg/m2 Sample size: From a previous study, considering a standard deviation of 16.2 min induration of effective analgesia with isobaric levobupivacaine and assuming the same standard deviation for 0.4mg and 0.6mg of nalbuphine as an adjuvant to levobupivacaine, to estimate a mean difference of 20 min with 0.4mg of nalbuphine and 30 min with 0.6mg of nalbuphine, at α= 5% and power = 90%, a sample size of minimum 10 patients are required in each group. Given the time and clinical cases of lower limb fracture, a minimum of 20 patients will be enrolled in each group. Methods: 40 patients planned for lower limb orthopaedic surgeries will be taken and randomly allocated into 2 groups as follows: Group-A: 15 mg of 0.5% levobupivacaine (3 ml) + 0.4mg nalbuphine hydrochloride(0.2ml) + normal saline (0.1 ml). Group-B: 15 mg of 0.5% levobupivacaine (3 ml) + 0.6mg nalbuphine hydrochloride (0.3 ml). - The total volume of drug in both the groups will be 3.3 ml. - Study drug will be prepared by an anaesthesiologist who is not involved in the study. - Under all aseptic precautions subarachnoid block will be performed as per standard protocol. Patients will be assessed for quality of sensory and motor block, hemodynamic parameters, pain score, sedation score and side effects. Outcome measures: Primary outcome: Analgesic efficacy: Duration of effective analgesia (time from the subarachnoid block to the time of patient’s first complaint of pain with VAS ≥3) Secondary outcome: 1) Quality of sensory block: -​Time of onset of sensory block (when the sensory block is achieved at level of T10 dermatome) -​Maximum block height. -​Time of two segment regression of sensory block (regression of two segments from the maximum block height achieved) 2) Quality of motor blockade: -​Modified Bromage Scale. -​Quality of muscle relaxation. -​Onset of motor blockade (time interval from intrathecal injection to the Modified Bromage Grade 1 is achieved) -​Duration of motor blockade (time interval from onset of motor block to regression of motor block to Modified Bromage Grade 0) 3) Adverse effects like nausea, vomiting, hypotension, bradycardia and pruritis etc. Statistical analysis: One time measurements between the groups will be compared by Unpaired Student’s t-test/ Mann-Whitney U test depending upon the nature of the data. Qualitative data will be analysed using Chi-square test/ Fischer’s Exact test. Repeatedly measured parameters will be compared by Repeated Measure ANOVA followed by Dunett’s test. A p- value <0.05 will be considered significant. |