Paediatric epidural analgesia with “top-up” doses: evaluation of its effectiveness and side effects

Introduction : Drugs can be administered epidurally through continuous infusion or multiple intermittent top-up doses. The top-up method is used less frequently in paediatrics, which is reflected by a small number of reports regarding this subject.

Aim of the study: The objective of this study was to evaluate the effectiveness and side effects of epidural analgesia with intermittent doses of bupivacaine as well as bupivacaine with morphine in children during the first 24 hours after thoracosurgery.

Material and methods : The observation prospective study included 84 children, aged between 7 and 18 years, divided into two subgroups. Operated children were given bolus doses in the following pattern: 0.25% bupivacaine administered every 4 hours according to Schulte-Steinberg formula, i.e. V (ml) =

12 segments x (0.1 x age in years) in group I (n = 30), and 0.25% bupivacaine with 2 mg morphine/20 ml administered every

8 hours according to modified Bromage formula, i.e. V(ml) = 1.2 ml x 10 segments + 0.1 ml per segment for each 10 cm height above 120 cm in group II (n = 54). Group II was also given prophylaxis antiemetic ondansetron and metoclopramide.

Results: Out of 89 patients eligible for the study, five children (5.6%) were excluded from the analysis because of the following complications: dura mater puncture, unintended complete spinal analgesia, vascular penetration of the catheter, leakage around the place of catheter insertion, and spontaneous ejection of the catheter. Data from 84 (94.4%) patients were analysed. Patients from group I experienced significantly stronger pain than patients from group II and required two times bigger daily dose of bupivacaine and four times higher dose of other supplementary analgesics. No significant differences regarding the frequency of postoperative complications between both groups were observed with the exception of skin itching recorded only in the group receiving morphine (24.1%). Generally, the following side effects were observed: nausea (8.3%), vomiting (36.9%), urinary retention (7.1%), paresthesia (8.3%), and general muscle tremor (2.4%).

Conclusions : Analgesia with bupivacaine and morphine is more effective than bupivacaine alone. The addition of morphine to bupivacaine solution increases the time of epidural block from 4 to 8 hours and decreases the demand for bupivacaine and supplementary analgesics. The method of intermittent top-ups is safe under the condition of continuous monitoring of patient’s status, which allows early detection and treatment of potential complications.