The efficacy of intrathecal injection of sufentanil using a microspinal catheter for labor analgesia

Intrathecal sufentanil can provide labor analgesia. We investigated the efficacy of multiple injections and the maternal and neonatal effects of intrathecal sufentanil during labor. Seventeen healthy women in active labor received multiple injections of intrathecal sufentanil of 5 mu g each through microspinal catheters. Overall maternal satisfaction of analgesia was quantified using 10 cm visual analogue scales and side effects were evaluated. Neonatal outcome was also determined. Onset of analgesia was less than 5 min after the first injection and lasted approximately 148 min. Tolerance developed for the successive injections. The mean onset times were 12.9 and 20.1 min and the durations were 76.6 and 33.9 min for the second and third injections, respectively (P<0.05). Failure to obtain analgesia developed in all patients after the forth injection. No motor blockade was observed in any of the patients. Mild or moderate pruritus developed in 88% of the patients. Mean systolic blood pressure decreased by a maximum of 11.3% at 30 min and up to 90 min (P<0.05) after the first injection; three patients required ephedrine treatment. No significant hemodynamic changes were observed after subsequent injections. Five patients experienced transient decrease in sensation. Neonatal status, as evaluated by Apgar scores, Neurological Adaptive Capacity Scores (NACS), fetal heart rate (FHR), and umbilical cord acid-base status, were within normal limits. Results from our study suggest that multiple small doses of sufentanil administered intrathecally provided satisfactory analgesia for parturients with short duration of labor since acute tolerance developed with multiple injections. High incidence of mild or moderate pruritus was observed during the study. Close attention should be given to hemodynamically unstable patients when this technique is applied.