A COMPARISON OF THE EFFECT OF INTRATHECAL AND EXTRADURAL FENTANYL ON GASTRIC-EMPTYING IN LABORING WOMEN

We studied gastric emptying, using acetaminophen absorption, in 105 wo men in labor divided into three equal groups of 35 each, after intrath ecal (IT) (25 mu g, Group S) or extradural (50 mu g, Group E) fentanyl in combination with bupivacaine and compared with a control group (Gr oup C) receiving extradural bupivacaine only. The time to maximal acet aminophen concentration (tCa(max)), maximal acetaminophen concentratio n (Ca-max), and areas under the acetaminophen concentration-time curve at 90 and 120 min (AUC(90) and AUC(120), respectively were determined . Median (range) tCa(max) values were 120 (15-180), 82.5 (15-180), and 90 (15-180) mill in Groups S, E, and C, respectively (P < 0.05). Mean +/- SD Ca-max was 13.4 +/- 8.82, 17.9 +/- 8.06, and 15.0 +/- 6.22 mu g/mL in Groups S, E, and C, respectively (P < 0.05). Mean +/- sn AUC(9 0) and AUC(120) were also significantly smaller in Group S than in the other two groups (430 +/- 616, 736 +/- 504, and 672 +/- 453; and 649 +/- 592, 1063 +/- 627, and 1053 +/- 616 mu g.mL(-1).min(-1) in Groups S, E, and C,respectively). We conclude that the administration of fent anyl 25 mu g IT delays gastric emptying in labor compared with both ex tradural fentanyl 50 mu g with bupivacaine and extradural bupivacaine alone. Implications: We examined emptying of the stomach in women in l abor after administration of analgesics by the spinal or the epidural route. We observed that the analgesic, fentanyl, administered by the s pinal route, although relieving pain rapidly, may delay emptying of th e stomach, Ln theory, delayed gastric emptying may increase the chance of vomiting and aspiration of gastric contents.