[Epidural perfusion with fentanyl in the treatment of postoperative pain]

In 40 patients with high abdominal surgery the analgesia achieved with continuous epidural phentanyl infusion was evaluated. Treatment was started when the patients had pain, with the injection of 150 micrograms of phentanyl in 18 ml of saline and going on with the infusion. The patients were divided in 4 groups. Each received a different infusion dose. The variables pain, alertness, pO2, pCO2 and hemodynamic status at the beginning of infusion and after 6, 18 and 24 hours were evaluated. All patients had an adequate postoperative analgesia. In the statistical analysis the only significant difference was an increase in pCO2 after 24 h in the patients who received the highest doses. The incidence of nausea and vomiting was 10%, with 13.04% of urinary retention Clinical respiratory depression was not observed. We think that administration of 150 micrograms of epidural phentanyl followed by a continuous epidural infusion of the drug (0.5 microgram/kg/hour in 5 ml of saline) is an adequate technique of postoperative analgesia.