Plasma concentrations of bupivacaine during continuous epidural anaesthesia in children

Epidural anaesthesia is extremely useful in providing postoperative analgesia for children after surgery of the lower body. Although results on early pharmacokinetics in children have previously been reported, no data are available on the long-term effects of epidural anaesthesia. The aim of this investigation was the assessment of plasma bupivacaine levels in children with continuous epidural anaesthesia in the postoperative period. A catheter with an outer diameter of 0.63 mm was inserted through a 19G Tuohy cannula into the epidural space. A maximum dose of 0.4 mg/kg/h bupivacaine was administered for continuous epidural infusion. Careful monitoring was performed to detect early signs of local anaesthetic intoxication. Two milliliters of blood were obtained in each patient per day and nepholometric serum measurement were performed to determine alpha(1)-acid glycoprotein and albumin levels. Bupivacaine plasma concentrations were assessed according to the method described by Sattler et al.[25]. Ten children were included in the investigation. The measured albumin and alpha(1)-acid glycoprotein concentrations were within the range described by other investigators. At the onset of pain therapy maximum levels of 0.5 mu g/ml where recorded after a loading dose of bupivacaine and levels of up to 2.2 mu g/ml were achieved following continuous infusion. There were no neurologic complications or signs of lokal anesthetic intoxication. In conclusion our results show that a dose of up to 0.4 mg/kg/h bupivacaine during continuous epidural infusion is not associated with toxic complications. Careful monitoring of the children by experienced staff is mandatory.