Risk of high spinal anesthesia following failed epidural block for cesarean delivery.

Recent case reports suggest there may be an increased risk of abnormally high blockade ("high spinal") from subarachnoid anesthesia if it is performed immediately after epidural anesthesia. We describe two cases of high spinal anesthesia following failed epidural block in obstetric patients scheduled for cesarean delivery. Using a retrospective chart review, we estimate the incidence of high spinal anesthesia to be 11% in patients after prior failed epidural blockade versus fewer than 1% in patients undergoing spinal anesthesia alone.