In Reply:-Although we did not have access to technical details about epidural placement in our study, we agree with Dr. Gevirtz et al. that several alterations in anesthetic technique have improved our safety with regional anesthesia in obstetrics. Common teaching in the 1970s and 1980s (experienced by several of our authors) was to perform obstetric epidurals with single bolus doses of 10–15 ml of 0.5% bupivacaine for labor or 20–25 ml of 0.75% bupivacaine for cesarean section. In contrast, test doses and incremental dosing through a catheter are now routine, and spinal anesthesia is increasingly used for cesarean section. Many anesthesiologists are using very small intrathecal doses of narcotics or local anesthetics to initiate labor analgesia followed by low-dose infusions. In our current practices, parturients will rarely be exposed to large concentrated bolus doses of epidural local anesthetics.
Joy L. Hawkins, M.D.
Associate Professor of Anesthesiology
University of Colorado School of Medicine
Denver, Colorado 80262