Comparisons of two different doses of fentanyl for procedural analgesia during epidural catheter placement: a double-blind prospective, randomized, placebo-controlled study.

The purpose of this study was to investigate the effect of fentanyl on analgesic properties and respiratory responses during an epidural procedure. Sixty patients premedicated with oral brotizolam 0.25 mg were allocated to receive procedural analgesia with saline or 25 or 50 μg of fentanyl. Five minutes after administration, an epidural procedure was started. Pain assessments were made immediately after the epidural catheter placement using a visual analog scale. The lowest SpO₂ levels during the procedure were recorded to evaluate respiratory depression, and cardiovascular complications were also recorded. The pain scores were significantly lower in the 25 and 50 μg fentanyl groups than in the placebo group (P < 0.01). There was no difference in pain assessment between the 25 and 50 μg fentanyl groups. The lowest SpO₂ value of the 50 μg fentanyl group was significantly lower than those of the other groups (P < 0.001). Seven of 20 cases in the 50 μg fentanyl group needed oxygen administration because of a decreased SpO₂ value (<94%). No cardiovascular complications were observed in any group during the entire study period. Thus, intravenous fentanyl at a dose of 25 μg provides effective procedural analgesia without the risk of hypoxemia during an epidural procedure in a patient with preanesthetic medication.