EFFECTS OF EPIDURAL BUPIVACAINE AFTER THORACOTOMY

Background and Objectives. Combinations of bupivacaine and fentanyl ar e popular for postoperative epidural analgesia. However, there are lit tle data from which to select a rational dose of bupivacaine. The stud y examined the effects of increasing amounts of epidural bupivacaine o n postoperative analgesia, epidural fentanyl consumption, and side eff ects after thoracotomy. Methods. Twenty-four patients were randomized in a double-blind manner to receive intra- and postoperative epidural infusions of either saline, 0.01% bupivacaine, 0.05% bupivacaine, or 0 .1% bupivacaine at 10 mL/h. All patients received a standardized combi ned epidural (120 mg lidocaine and 1.5 mu g/kg of fentanyl) and genera l anesthesia. Further postoperative analgesia was provided with fentan yl patient-controlled epidural analgesia (PCEA) only. Results. There w ere no differences between groups in visual analog scale (VAS) pain sc ores at rest or cough, but 10 and 5 mg/h of bupivacaine provided bette r analgesia during physiotherapy (P <.05). The use of 10 and 5 mg/h of bupivacaine led to significant opioid sparing (50% decrease) when com pared to saline and 1 mg/h bupivacaine (P <.03). There was a trend tow ard a greater incidence of orthostasis with the use of bupivacaine at 10 mg/h (P =.09). Incidences of opioid side effects were not different between groups. Conclusions. The results demonstrate improved analges ia with physiotherapy and significant opioid sparing when 10 and 5 mg/ h doses of bupivacaine are used. However, the incidence of orthostasis may be increased with the use of 10 mg/h. Thus, 5 mg/h of epidural bu pivacaine (.05% at 10 mL/h) improved anal gesia, decreased opioid requ irements, and did not have detectable hemodynamic effects.