[Prolonged epidural analgesia following thoracotomy. Clinical study and serum levels over five days].

Prolonged continuous epidural analgesia allows perithecal infusion with fentanyl and bupivacaine for 5 postoperative days after thoracic surgery. This study included 27 thoracotomized patients randomised into two groups: group X consisted of 15 subjects, group Y consisted of 12 subjects. Each patient received 33 micrograms/hr or fentanyl for 48 hours, associated with 0.25% bupivacaine in group X, and 0.125% bupivacaine in group Y. Over the three last days, the infusion rate of both drugs was decreased in the two groups. No significant clinical difference appeared between X and Y. No clinical respiratory depression occurred. In group Y, mean plasma bupivacaine concentrations remained significantly lower (p less than 0.05). Mean fentanyl levels did not increase beyond 0.8 ng/ml. The use of 0.125% bupivacaine improved the margin of safety but did not impair clinical analgesia in the study. This method provides good analgesia for thoracotomized patients.