Letters to the Editor: Letters & Announcements
I appreciate Dr. Balestreiri’s comments. I share his lack of enthusiasm for utilizing an indwelling epidural catheter for postpartum tubal ligation, or at least a catheter that has remained in place for an extended period postdelivery. However, my reasons and concerns only partially overlap with his.
As Dr. Balestreiri notes, the failure rate of an epidural catheter under such circumstances can be appreciable. And management of such failures is complicated by the unpredictable, and often excessive, anesthesia that may accompany a spinal anesthetic after a failed epidural (1). Consequently, similar to Dr. Balestreiri, it is my personal practice to remove an epidural catheter after several hours of disuse and administer a single-injection spinal to provide anesthesia for postpartum tubal ligation.
The issue of toxicity is a bit more complicated. Although it is well established that epidural catheters cannot penetrate intact dura (2), subarachnoid “migration” does occur in clinical practice. It is possible that this might occur more frequently with an indwelling catheter without infusion, but this would be pure speculation, at best. In any event, avoidance of injury—which is a risk with intrathecal injection of epidural doses of chloroprocaine, lidocaine (3), or any anesthetic—rests in careful assessment of the catheter’s position, achieved through a combination of aspiration, administration of a test dose, and fractionated administration of anesthetic.
Kenneth Drasner, MD
Department of Anesthesia and Perioperative Care
University of California, San Francisco
San Francisco General Hospital
San Francisco, CA
1. Mets B, Broccoli E, Brown AR. Is spinal anesthesia after failed epidural anesthesia contraindicated for cesarean section? Anesth Analg 1993;77:629–31.
2. Hardy PA. Can epidural catheters penetrate dura mater? An anatomical study. Anaesthesia 1986;41:1146–7.
3. Drasner K, Rigler ML, Sessler DI, Stoller ML. Cauda equina syndrome following intended epidural anesthesia. Anesthesiology 1992;77:582–5.