Does epinephrine improve the diagnostic accuracy of aspiration during labor epidural analgesia?
Aspiration reliably detects almost all IV multiorifice epidural catheters. Although a supplemental epinephrine 15-microg test dose may detect the rare IV catheter that does not yield blood on aspiration, false-positive epinephrine responses may cause some women to unnecessarily undergo repeat epidural catheter insertion. We evaluated 532 consecutive eligible patients requesting neuraxial labor analgesia. Patients were excluded if they had a contraindication to epinephrine or if they received intrathecal sufentanil/bupivacaine. Multiorifice catheters were inserted 4-6 cm into the epidural space as part of an epidural (n = 305) or combined spinal-epidural (n = 270) technique. We used aspiration, a lidocaine/epinephrine test dose, and bolus injection or infusion of dilute bupivacaine/sufentanil solutions to systematically determine IV, intrathecal, or epidural catheter location. Aspiration alone detected 47 of 48 intravascular catheters. There were 10 positive epinephrine responses: 2 wer