Thoracic versus lumbar administration of fentanyl using patient-controlled epidural after thoracotomy

Epidural fentanyl injection can provide analgesia following thoracotomy, but where to insert the catheter is a matter of debate. The study compares the effects of thoracic and lumbar patient-controlled epidural fentanyl on analgesia, fentanyl requirements, and plasma levels after thoracotomy.

Thirty patients were randomized into two groups to receive either thoracic or lumbar patient-controlled epidural fentanyl for postoperative analgesia. Postoperative pain (10 cm, visual analog scale [VAS]) and fentanyl requirements were assessed every 4 hours for 24 hours and at 12-hour intervals for the next day. Fentanyl plasma levels were measured at 8 and 16 hours after surgery. Results were expressed as mean +/- 1 SD and analyzed using Student's t-test, ANOVA, and chi-square analysis at P < .05.

Twenty-nine patients completed the study (14 in the lumbar and 15 in the thoracic group). The VAS scores and fentanyl requirements were not significantly different at any time interval in the thoracic group as compared to the lumbar group. VAS scores at 0 hours (4.6) and 4 hours (4.6) in the lumbar group were higher than VAS scores at 12 hours (2.8; P = .04), 16 hours (2.5; P = .02), and 20 hours (2.2; P = .01) in the same group. No significant difference was found between the fentanyl plasma levels of the two groups after 8 hours (lumbar, 0.26 +/- 0.37 ng/mL; thoracic, 0.22 +/- 0.20 ng/mL) or 16 hours (lumbar, 0.36 +/- 0.17 ng/mL; thoracic, 0.44 +/- 0.32 ng/mL).

The authors concluded that there is little if any advantage of thoracic over lumbar patient-controlled epidural fentanyl administration in patients after thoracotomy with respect to analgesia, fentanyl requirements, and plasma levels.