CONTINUOUS HIGH THORACIC EPIDURAL ADMINISTRATION OF MORPHINE WITH BUPIVACAINE AFTER THORACOTOMY

Background and Objectives. The purpose of the study is to determine th e ideal concentration of morphine when given with bupivacaine as a con tinuous high thoracic epidural infusion for postthoracotomy pain. Meth ods. In a prospective study, 60 patients scheduled for thoracic surger y received a high thoracic epidural catheter. Postoperative analgesia was provided by a continuous epidural infusion for 3 days. The patient s were randomly divided into two groups: group 1 (loading dose 1 mg mo rphine epidurally and continuous infusion of bupivacaine 0.75% + 0.2 m g/mL morphine at an infusion rate of 0.8 mL/hr); group 2 (loading dose 0.5 mg morphine epidurally and continuous infusion of bupivacaine 0.7 5% + 0.1 mg/mL morphine at an infusion rate of 0.8 mL/hr). Results. Th e visual analog scales were not different at rest but with exercise in group 1 there was better pain relief than in group 2. The number of p atients requiring supplementation of analgesia in group 2 (n = 42) was six times that of group 1 (n = 7). PaCO2 increased in both groups dur ing the first postoperative day. There was no difference in the incide nce of side effects between the two groups. Conclusions. Continuous hi gh thoracic epidural administration 0.2 mg/mL morphine in bupivacaine 0.75% at an infusion rate of 0.8 mL/hr with a loading dose of 1 mg mor phine is an effective dose for postthoracotomy pain relief in rest, an d more important, during exercise.