Postsurgical Analgesic Efficacy of Epidural Nalbuphine in Lower Abdominal Surgeries

ABSTRACT

Epidural analgesia has been the gold standard, preferred technique for providing postoperative analgesia in lower abdominal, lower limb, pelvic and vascular surgeries. Combination of local anaesthetic agents when used along with opioids, as an adjuvant in epidural analgesia, was found to be effective and synergistic. Ropivacaine is associated with less central nervous system toxicity and cardiotoxicity, and produces less motor blockade. Nalbuphine is an opioid with mixed kappa (κ) agonist and mu (µ) antagonistic properties, when mixed with other opioids, attenuates the µ opioid effect and enhances the κ opioid effect. We wanted to compare the post-surgical analgesic efficacy of epidural nalbuphine (10 mg) when added as an adjuvant to epidural ropivacaine (0.2%-9 ml) in patients undergoing lower abdominal surgeries. Primary objective was to compare the duration of postoperative analgesia and number of rescue analgesics required in 24 hours. Secondary objectives were to compare postoperative haemodynamic variation, quality of analgesia, Visual Analogue Score and side effects if any in both the groups.METHODSIt was prospective observational study conducted after obtaining ethical committee clearance. Sixty patients of ASA class I & II, fulfilling inclusion criteria posted for elective lower abdominal surgeries preferably abdominal hysterectomies divided into two groups, each comprising of 30 patients; group R- Ropivacaine- 0.2% - 9 ml with 1 ml normal saline and group R+N - 0.2%- 9 ml with nalbuphine 1 ml - 10 mg, under spinal anaesthesia with epidural catheter insertion. Parameters like duration of analgesia, number of rescue analgesia, quality of analgesia by patient rated quality of pain management, haemodynamic variation was assessed. Assessment of pain was done by VAS scale, side effects like sedation was assessed by modified Ramsay sedation scale.RESULTSNo demographic variation was found in any group. Mean duration of analgesia was found more in group R+N. Number of rescue analgesia was reduced in group R+N with improved quality of analgesia which was statistically significant. Mean HR was significant in group R+N. No change was noted in SBP, RR, SpO2 in either group. DBP and MAP showed statistically significant difference at 30, 60 min and 15, 30, 60 min respectively. None of the patients in either group had sedation; one episode of vomiting was noted in group R+N with statistically non-significant results.