A comparative evaluation of three different doses of Epidural Neostigmine coadministered with Levobupivacaine for postoperative analgesia after lower limb Orthopedic surgeries

Abstract

Background: Intrathecal neostigmine produces analgesia but its utility is limited by increased incidences of nausea and vomiting. However, epidural neostigmine has been investigated to produce postoperative analgesia without nausea and vomiting. The purpose of the current study was to define the dose range for analgesic effectiveness of epidural neostigmine co-administered with levobupivacaine and side effects in patients after lower limb orthopedic procedures. Patients & Methods: After Institutional Ethical committee approval and informed written consent, 120 patients (n = 30) undergoing lower limb orthopedic surgery were randomly allocated to one of four groups and studied in a prospective way. Patients were randomized to receive either saline or 50, 100, or 150 µg neostigmine in 1ml as adjuvant to Levobupivacaine 0.5%, 20 ml (n = 30 per group), epidurally. Onset and duration of analgesia and motor block was assessed using pin prick, visual analogue scale (VAS) and bromage scale for 22 hrs. peri-operatively. Any side effects were also observed. Results: Groups were demographically the same and did not differ in intraoperative vital characteristics (heart rate and respiratory rate), however there was some protection from hypotension observed in neostigmine 100 and 150 µg group. Addition of neostigmine resulted in significant longer duration of analgesia in group III (490±105.2 mins) and group IV (542±133.6 mins) than control group I (335±101.3 mins). The time of onset of analgesia (7.2 mins versus 9.2 mins in control) and motor block (12.4 and 11.5 mins versus 17 mins in control) was also decreased significantly. Two patients in control and one patient in group III developed nausea/vomiting which was statistically insignificant. There was no other incidence of increased side effects in any group. Conclusion: Co-administration of epidural neostigmine and levobupivacaine appears to be a useful technique for perioperative analgesia as it increases duration of ana