A COMPARISON OF INTRATHECAL, EPIDURAL, AND INTRAVENOUS SUFENTANIL FOR LABOR ANALGESIA

A number of recent studies have suggested that the analgesic effects of highly lipid-soluble opioids are similar when these agents are administered either epidurally or intravenously. We sought to test whether the lipid-soluble opioid sufentanil was more effective when administered intrathecally than when administered epidurally or intravenously. Twenty-four women during active labor received sufentanil 10 mug either intrathecally (n = 9), epidurally (n = 8), or intravenously (n = 7), using a combined spinal-epidural technique. The sufentanil was administered alone, without concomitant local anesthetics. Analgesia was assessed using the visual analogue score as well as the time elapsed from the administration of study drug to the patient's request for additional analgesia via the epidural catheter (bupivacaine 0.25%). The median duration of analgesia (median, interquartile range) was 84 (70-92) min in the intrathecal group, 30 (23-32) min in the epidural group, and 34 (17-30) min in the intravenous group (P < 0.001). The intrathecal group showed rapid and significant decrease in visual analogue scale scores, whereas visual analogue scale scores in the other two groups did not decrease and remained significantly elevated compared to those of the intrathecal group at all observation points. Side effects were limited to pruritus in 3 patients (2 moderate and 1 severe) in the intrathecal group. No patient developed post-dural puncture headache. We conclude that sufentanil 10 mug intrathecally provides rapid and effective analgesia of 1-2-h duration during labor. Epidural and intravenous use of this dose of sufentanil did not provide evidence of satisfactory analgesia. Increased efficacy after intrathecal injection of sufentanil 10 mug suggests a spinal site of action by this route.