DIRECT THORACIC PLACEMENT OF EPIDURAL CATHETERS IN INFANTS AND CHILDREN

Abstract

S295 INTRODUCTION: Epidural catheter tip placement closest to the dermatome innervating the incision site has several advantages when infusing local anesthetics in infants and children. The lower volume of the local anesthetic required limits the potential for toxicity. The proximity of the catheter tip to the surgical site limits the degree of lateral spread of local anesthetic out of the intervertebral foramina following bolus injections. Several investigators have described successful threading of thoracic catheters from the caudal or lumbar epidural space. However, this approach is not entirely reliable (e.g. 23% above T10 in one infant study [1]), and perhaps not entirely benign in terms of disturbing epidural septa. METHODS: Using a prospectively collected database, 144 infants and children having direct placement of a thoracic epidural catheter from July '94 to July '98 were examined for age, procedure, level of placement, duration of infusion, side effects and complications. All catheters were placed after induction of general anesthesia and prior to surgical incision under the direction of an experienced attending anesthesiologist. For children less than 30kg, an 18g 2 in Weiss needle was used with a 20g catheter and for children greater than 30kg, a 17g 3.5 in Weiss needle with a 19g catheter was used. Needles were advanced using a continuous loss of resistance to saline technique. Catheters were threaded 1-3 cm. Intraoperative analgesia was provided with 0.5% or 0.25% bupivacaine. Postoperative analgesia was provided with an infusion of 0.1% bupivacaine with fentanyl, 1-2mcg/ml at a rate of 0.2 to 0.4 ml/kg/hr. RESULTS: The mean age was 9.3 yrs (8 days to 18yrs). Placement level ranged from T6 to T10. The distribution of surgical cases was: pectus excavatum repair 36%, thoracotomy 29%, thymectomy 6.9%, sternotomy 3.5%, nephrectomy 4.8%, laparotomy 18.5% and management of rib fracture 1.4%. Duration of infusions were for an average of 3 days (range 1-5 days). Analgesia was satisfactory in all but one patient whose catheter was not clearly functioning intraoperatively. Ketorolac was administered to 5% of the thoracotomy patients for shoulder pain. There was no incidence of respiratory depression. Minor adverse events included pruritus 2%, nausea or vomiting requiring treatment and a 2% incidence of Horner's syndrome which resolved with a reduction in infusion rate. DISCUSSION: This series demonstrates the feasibility and effectiveness of this technique in the population studied. The data, however, may still be insufficient to prove the safety of the technique for other children or where employed by less experienced personnel. The low incidence of pruritus when compared to a previously reported pediatric thoracic epidural series [2] may have been due to the fact that fentanyl was never given as a bolus injection, but was instead given as a continuous infusion. The database has been useful for identifying performance improvement issues and has been used in designing protocols for the management of various postsurgical populations, (e.g. pectus repair).