THE EFFECTS OF EPIDURAL OPIOIDS ON FETAL HEART-RATE-VARIABILITY WHEN COADMINISTERED WITH 0.25-PERCENT BUPIVACAINE FOR LABOR ANALGESIA

Assessment of fetal heart I-ate (FHR) variability provides important i nformation regarding fetal well-being. Normal FHR variability is gener ally associated with fetal normoxia. Opioids are frequently co-adminis tered with local anesthetics to provide epidural analgesia for labor. Epidural opioid effects on FHR variability have not been extensively s tudied. In a double-blind, randomized study, 109 parturients had their epidural catheter injected with either butorphanol (2 mg), fentanyl ( 50 mu g), sufentanil (15 mu g) or saline and bupivacaine (0.25%). FHR tracings of 30 min duration were obtained both before and after epidur al analgesia. Each of the 218 tracings was randomly numbered and later graded by the same individual for short- and long-term variability. T he two 30-min tracings for each patient were then palled but not order ed as to which tracing was ''pre-epidural'' or ''postepidural'' and ag ain compared for change in short- and long-term variability between th e paired tracings. The paired tracings were then Ordered as ''pre-epid ural'' or ''postepidural.'' A designation was made whether long-term v ariability was increased, decreased, or stayed the same after inductio n of epidural analgesia. Short-term variability was initially present in all patients. There were no changes in short-term variability after induction of epidural analgesia. There was no difference in long-term variability in any group receiving opioids as compared to control. Th ere was no difference in the change in long-term variability after ind uction of epidural analgesia. The addition of butorphanol, fentanyl, o r sufentanil to epidural bupivacaine (0.25%) does not change FHR short - or long-term variability.