CAN PARTURIENTS DISTINGUISH BETWEEN INTRAVENOUS AND EPIDURAL FENTANYL

We tested the hypothesis that the sedative, euphoric, and analgesic ef fects of intravenous fentanyl would distinguish intravenous from epidu ral administration. One hundred RSA I and II labouring parturients rec eived 100 mu g fentanyl either iv or via an epidural catheter in a dou ble-blind, randomized, crossover fashion. Nineteen anaesthetists (8 st aff and 11 residents) participated and correctly guessed the route of administration of the fentanyl in 61/66 intravenous doses and in 69/75 epidural doses yielding a sensitivity of 92.4%, a specificity of 92.0 %, a positive predictive value of 91.0%, and a negative predictive val ue of 93.2%. Of the 41 patients that were crossed over, 38 (92.7%) wer e able to detect a difference between the routes of administration. Mo st patients experienced prompt, short-lived symptoms with iv fentanyl but no important differences in fetal heart rate pattern or in materna l desaturation were seen between the groups. This study suggests that subjective symptoms will accurately distinguish intravenous from epidu ral fentanyl administration in labouring parturients (P < 0.001), and should serve as a safe and reliable intravenous test dose for epidural anaesthesia in the obstetric population.