Intrathecal buprenorphine as an adjuvant to 0.5% bupivacaine in vaginal hysterectomy

Background: One of the most suitable modality of anaesthesia for lower abdominal surgeries is spinal anaesthesia. The relatively short duration of action of local anaesthetics necessitates the supplementation of local anaesthetics with adjuvants which help to reduce the dose of local anaesthetic, minimize side effects and prolong the duration of anaesthesia at a relatively lesser cost to the patient. Aim: To evaluate the characteristics of subarachnoid block, the postoperative analgesia and side effects of intrathecal buprenorphine 150 µg when used as adjuvant to 0.5% bupivacaine, for vaginal hysterectomy. Materials and methods: After approval from the hospital ethical committee and informed consent from the patients a prospective pilot study was undertaken to evaluate the efficacy of intrathecal buprenorphine when used as an adjuvant to 0.5% bupivacaine. All patients belonged to American Society of Anesthesiologist's Physical status I and II and aged between 33 and 60 years. Patients were allocated into two groups. Group A were to receive 0.5% bupivacaine 2.5 mL. Group B were to receive 0.5% bupivacaine 2.5mL with buprenorphine 150 µg. It was observed that most of group A patients had to receive general anaesthesia in addition to subarachnoid block due to inadequate pain relief. The data of group B patients were analysed. Results: Of the 49 patients analyzed, 13 patients had pain free interval which lasted more than 24 hours. Twelve patients who received a single dose of diclofenac 75 mg intravenously before the onset of pain had a pain free interval which lasted more than 24 hours. The average duration of analgesia of 37 patients was 1027 minutes ± 706.662. Conclusions: A single dose of intrathecal buprenorphine 150 µg added to bupivacaine may provide analgesia for a significant length of time in patients who have undergone vaginal hysterectomy without significant side-effects.