Epidural and intravenous fentanyl produce equivalent effects during major surgery

The benefit of epidural versus intravenous fentanyl administration for postoperative analgesia is controversial. In the current study, the intraoperative effects of epidural versus intravenous fentanyl administration were compared during major surgery.

Twenty elective patients scheduled for thoracoabdominal esophagectomy under general anesthesia with propofol infusion were randomly allocated to receive either intravenous or epidural boluses of 50-100 micrograms fentanyl in a double-blind fashion to maintain hemodynamic stability. Plasma cortisol and fentanyl, as well as total urinary catecholamines, were obtained at the end of the operations.

Hemodynamic variations were similar except that patients receiving epidural fentanyl had a lower incidence of heart rate reduction (> 20% reduction from baseline, P < 0.05). There were no differences in mean intraoperative fentanyl (1,115 +/- 430 and 1,010 +/- 377 micrograms, epidural and intravenous, respectively) or propofol (2,281 +/- 645 and 2,452 +/- 1,169 mg) doses, number of boluses of fentanyl (nine in both groups), plasma fentanyl concentration (1.13 +/- 0.4 and 1.02 +/- 0.46 ng/ml), or number of anesthesiologists correctly identifying the site of fentanyl administration. Similarly, there were no differences in plasma glucose (8.9 +/- 1.8 and 9.3 +/- 1.8 mM) and cortisol (696 +/- 446 and 846 +/- 257 mM), or urinary epinephrine (12 +/- 3.7 and 13.1 +/- 9.2, micrograms/sample) and norepinephrine (42.7 +/- 26.7 and 39.1 +/- 27.6, micrograms/sample).

There appears to be no clinical advantage to epidural administration of fentanyl over intravenous administration during anesthesia for major surgery.