Optimal dose of fentanyl for postoperative epidural analgesia after thoracic surgery

BACKGROUND: We investigated the dose of fentanyl in ropivacaine for epidural anesthesia that will provide effective analgesia with minimal side effects after thoracic surgery. METHODS: Sixty patients scheduled to undergo thoracic surgery were randomly allocated to four groups according to fentanyl dose in epidural analgesia: group R (0 microg x hr(-1); n = 15), group F1 (5 microg x hr(-1); n = 15), group F2 (10 microg x hr(-1); n = 15) and group F3 (15 microg x hr(-1); n = 15). Pain scores (visual analogue scale: VAS) were assessed at 1, 3, 6, 12, 24, and 48 hrs after surgery. Degrees of satisfaction regarding pain relief and complications during a period of 48 hrs after surgery were compared. RESULTS: Pain scores in group F3 were significantly lower than those in the other groups at 3, 6, and 12 hrs after surgery. The number of postoperative analgesics used in group R was significantly more than the numbers used in other groups. The incidences of side effects were similar in the four groups. CONCLUSIONS: We conclude that continuous epidural administration of more than 15 microg x hr(-1) of fentanyl in ropivacaine provides pain relief and few side effects after thoracic surgery.