Abstract
The technique review by Arendt and Segal1 in the Spring 2008 issue of Reviews in Obstetrics & Gynecology gives us broad insight on various causes of epidural analgesia failure. We would like to comment on the subject and share our experience.
The authors state that 6.8% of patients with initially successful blocks subsequently develop insufficient analgesia. Migration of the epidural catheter is given as the main cause of cessation of analgesia after a successful block. We agree with the authors that migration is a common problem in clinical practice, but we believe that an important factor that leads to pain despite successful epidural block during labor needs to be mentioned.
It is known that epidural analgesia during labor may increase the risk of developing urinary retention by 300%.2 Considerable amounts of fluid are given to patients receiving neuraxial blocks to prevent hypotension without the routine use of urinary catheters. Urinary retention causes abdominal pain that is sometimes interpreted as epidural failure. Therefore, we remind readers to consider urinary retention as a probable cause of pain and empty the patient’s bladder before looking for a solution for the migration of the epidural catheter.
Response
We appreciate the comments of Drs. Seza, Ates, and Soysal regarding our article. We agree that bladder distention may present as breakthrough pain in an otherwise well-functioning epidural catheter. In many institutions, however, urinary catheterization is routine when epidural labor analgesia has been initiated, which would make this phenomenon unlikely. In uncatheterized patients with diffuse abdominal pain, particularly if constant and unrelated to uterine contractions, consideration should be given to this diagnosis. Moreover, whenever a patient with an epidural complains of an unusual pattern of pain, the source of the discomfort should be identified before assuming that inadequate epidural blockade is the cause.
Scott Segal, MD
Katherine Arendt, MD
References
- 1.Arendt K, Segal S. Why epidurals do not always work. Rev Obstet Gynecol. 2008;1:49–55. [PMC free article] [PubMed] [Google Scholar]
- 2.Musselwhite KL, Faris P, Moore K, et al. Use of epidural anesthesia and the risk of acute postpartum urinary retention. Am J Obstet Gynecol. 2007;196:472.e1–472.e5. doi: 10.1016/j.ajog.2006.11.031. [DOI] [PubMed] [Google Scholar]