Effects of Epidural Bupivacaine After Thoracotomy

BACKGROUND AND OBJECTIVES: Combinations of bupivacaine and fentanyl are popular for postoperative epidural analgesia. However, there are little data from which to select a rational dose of bupivacaine. The study examined the effects of increasing amounts of epidural bupivacaine on postoperative analgesia, epidural fentanyl consumption, and side effects 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 combined epidural (120 mg lidocaine and 1.5 micrograms/kg of fentanyl) and general anesthesia. Further postoperative analgesia was provided with fentanyl patient-controlled epidural analgesia (PCEA) only. RESULTS: There were no differences between groups in visual analog scale (VAS) pain scores at rest or cough, but 10 and 5 mg/h of bupivacaine provided better analgesia during physiotherapy (P < .05). The use of 10 and 5 mg/h of bupivacaine led to significant opioid sparing (50% decrease) when compared to saline and 1 mg/h bupivacaine (P < .03). There was a trend toward 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 analgesia 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 bupivacaine (.05% at 10 mL/h) improved analgesia, decreased opioid requirements, and did not have detectable hemodynamic effects.