Vecuronium and fentanyl requirement in abdominal surgery under combined epidural-general anaesthesia and general anaesthesia alone

Individual effect of epidural block and general anaesthesia is well established in the field of anaesthesiology. But adequate literature is yet not available to give decisive answer regarding the requirement of muscle relaxants and opioid analgesic when the two methods are combined together. In the present study, sixty patients, aged 18-50 years of both sexes with ASA (American Society of Anesthesiologists) grading I and II scheduled to undergo for major abdominal surgery were assigned randomly into two groups (30 in each group), where Group A received general anesthesia and Group B received combined epidural-general anesthesia. The patients with combined technique, epidural catheter tip were placed between T9-10. Ten ml of 0.125% bupivacaine was administered through the epidural catheter. Peripheral nerve stimulator was used to monitor neuromuscular transmission and subsequently to administer incremental dose of neuromuscular blocking drugs. All the patients were pre-medicated with fentanyl (2μg/kg) to reduce intubation reflex. Then the patients of both groups were pre-oxygenated for 3 minute and anaesthesia was induced with thiopental sodium 3-5 mg/kg body weight. Endotrachial intubation was facilitated by vecuronium 0.1mg/kg body weight. Anaesthesia was maintained with 60% N2O in O2 and halothane (0.4 to 0.8%). Fentanyl was given in incremental dose of 0.5 μg/kg to maintain an adequate analgesia. The vecuronium was given at the dose of 0.02 mg/kg, when TOF return to 25% of the base line. The mean±SD requirement of vecuronium in general anaesthesia group was 0.0016±0.00013 mg/kg/min and whereas in combined epidural-general anaesthesia, it was 0.0011±0.00014 mg/kg/min. The requirement of fentanyl was 0.71μg/kg/hr in general anaesthetic group whereas in combined group it was 0.31μg/kg/hr. These findings prompt us to place optimal dosing guidelines so as to avoid overdosing and thus delay recovery and help to get the excellent outcome of the surgery.