A Comparative Study of Epidural Bupivacaine and Epidural Bupivacaine With Lowdose Butorphanol for Perioperative Analgesia in Patients Undergoing Elective Gynaecological Surgeries

BACKGROUNDEpidural anaesthesia with bupivacaine is a popular method of anaesthesia for gynaecological surgery.Several studies have already reported that opioids as neuraxial additive markedly prolonged the postoperative analgesic effect of local anaesthetics without much increase of adverse events.Sixty adult females of ASA physical status I and II, aged between 20 -60 years, scheduled for elective gynaecological surgery were included in this randomised double-blind controlled study.Aim of this study was to compare the efficacy of low-dose butorphanol as additive to epidural bupivacaine and epidural bupivacaine alone for perioperative analgesia. MATERIALS AND METHODSThe patients were randomly allocated into two equal groups to receive either 15 -20 mL of 0.5% bupivacaine hydrochloride (Group I, n = 30) or 15 -20 mL of 0.5% bupivacaine hydrochloride plus low-dose (0.5 mL) butorphanol tartrate (Group II, n = 30) according to computerised randomised table.The dose of 0.5% bupivacaine hydrochloride was calculated according to the height of the patient (i.e. 150 -160 cm: 15 mL and 160 cm onwards: 20 mL).Under all aseptic precautions, epidural anaesthesia was given with 18G Tuohy needle in sitting posture at L2-3 or L3-4 interspace using loss of resistance technique to identify epidural space.After negative aspiration test, the study drug was slowly injected as per protocol.No other analgesic was given to the patients intraoperatively.Onsets of sensory and motor block were assessed.Duration of sensory and motor block, height of block and duration of analgesia also were assessed.Time to first rescue analgesic was taken as the duration of analgesia; VAS and VRS scores at that point were also noted.The total number of doses of rescue analgesics required in first 24 hours was also noted.Blood pressure, heart rate and respiratory rate were recorded at stipulated intervals.Adverse events, if any were also noted.The data was analysed using appropriate statistical test. RESULTSThe onset and duration of sensory and motor blocks were comparable between the two groups.Duration of analgesia was significantly longer in patients receiving butorphanol additive group.Vital parameters were well maintained during intraoperative and postoperative period in both the groups.A few minor adverse events such as nausea, vomiting, pruritus and shivering were found in both the groups, but no significant difference on analysis. CONCLUSIONA single low-dose (0.5 mg) butorphanol along with epidural bupivacaine (0.5%) administration prolongs the duration of effective analgesia compared with bupivacaine (0.5%) alone.This low-dose (0.5 mg) butorphanol as additive does not appear to influence the speed of onset of blocks.Haemodynamic parameters and adverse events are also not influenced.