Lidocaine with fentanyl, compared to morphine, marginally improves postoperative epidural analgesia in children.

PURPOSE: To compare the epidural administration of fentanyl (1 microg/mL) combined with lidocaine 0.4% to preservative-free morphine for postoperative analgesia and side effects in children undergoing major orthopedic surgery.

METHODS

In a prospective, double-blind study, 30 children, ASA I-II, 2-16-yr-old, were randomly allocated to receive immediately after surgery either epidural F-L (epidural infusion at a rate of 0.1-0.35 mL/kg/hr of 1 microg/mL of fentanyl and lidocaine 0.4%) or epidural M (bolus of 20 microg/kg of morphine in 0.5 mL/kg saline every eight hours). Both groups received 40 mg/kg of iv metamizol (dipyrone) every six hours. In the F-L Group, blood samples were taken on the second and third postoperative day to determine total lidocaine concentrations. Adequacy of analgesia using adapted pediatric pain scales (0-10 score) and side-effects were assessed every eight hours postoperatively.

RESULTS

Resting pain scores were under 4, 95% of the time in the F-L Group and 87% of the time in the M Group (Chi square=4.674, P <0.05). The frequency of complications was very similar in both groups. The F-L Group total plasma lidocaine concentrations were directly related to the dose received, and below the toxic range in all patients.

CONCLUSIONS

Postoperative epidural fentanyl with lidocaine infusion provides slightly better analgesia than conventional bolus administration of epidural morphine. Side-effects or risk of systemic toxicity were not augmented by the addition of lidocaine to epidural opioids.