Intravenous lignocaine–fentanyl versus epidural ropivacaine–fentanyl for postoperative analgesia after major abdominal oncosurgery: A pilot prospective randomised study

Objective: Epidural injection of local anaesthetics and intravenous opioid injection are two common analgesic strategies following major abdominal oncosurgery. However, epidural local anaesthetics may cause haemodynamic instability while opioid injection is associated with sedation and postoperative ileus. Intravenous lignocaine is also used for postoperative analgesia, and combined use of opioids plus lignocaine can reduce the doses and adverse effects of the individual drugs. This study therefore compared the analgesic efficacy of intravenous lignocaine–fentanyl (IV) to epidural ropivacaine–fentanyl (EPI) after major abdominal oncosurgery. Methods: Sixty patients were randomised to IV and EPI groups. Patients in the IV group received preoperative intravenous bolus injections of lignocaine 1.5 mg kg⁻¹ and fentanyl 0.5 µg kg⁻¹, intraoperative infusions of lignocaine 1 mg kg⁻¹ h⁻¹ and fentanyl 0.5 µg kg⁻¹ h⁻¹, and postoperative infusions of lignocaine 0.5 mg kg⁻¹ h⁻¹ and fentanyl 0.25 µg kg⁻¹ h⁻¹. In the EPI group, patients received a 6-ml epidural bolus injection of ropivacaine 0.2% plus fentanyl 2 µg mL⁻¹, intraoperative infusion of 5 mL·h⁻¹ fentanyl and postoperative ropivacaine 0.1% plus fentanyl 1 µg mL⁻¹ infusion at 5 mL h⁻¹. All patients also received postoperative patient-controlled IV fentanyl as rescue analgesia. Patient-controlled fentanyl consumption was documented as the primary outcome for postoperative analgesic efficacy. Results were compared by Mann–Whitney U-test and Student’s t-test using Statistical Package for Social Science (SPSS) software. Results: Median (min–max) rescue fentanyl requirement in the first 24 h postsurgery was comparable between IV and EPI groups [780 (340– 2520) µg vs. 820 (140–2260) µg; p=0.6], as was postoperative pain score (p>0.05). The incidence of intraoperative hypotension requiring bolus mephenteramine injection was significantly higher in the EPI group than the IV group (36% vs. 17%; p<0.001). Conclusion: Intravenous lignocaine–fentanyl and epidural ropivacaine–fentanyl have comparable postoperative analgesic efficacies after major open abdominal oncosurgery.