pISSN 2005-9159
eISSN 2093-0569

Original Article

Korean J Pain 2009; 22(2): 124-129

Published online August 30, 2009 https://doi.org/10.3344/kjp.2009.22.2.124

Copyright © The Korean Pain Society.

The Aspiration of Injected Air via an Epidural Catheter as an Indicator for Appropriate Placement of the Catheter in the Epidural Space

Soon Ho Cheong, M.D., Dae Sik Park, M.D.*, Sung Ho Moon, M.D., Kwang Rae Cho, M.D., Sang Eun Lee, M.D., Young Hwan Kim, M.D., Se Hun Lim, M.D., Jeong Han Lee, M.D., Kun Moo Lee, M.D., Young Kyun Choe, M.D., Young Jae Kim, M.D., and Chee Mahn Shin, M.D.

Department of Anesthesiology and Pain Medicine, Pusan Paik Hospital, College of Medicine, Inje University, *Gupo Sungsim Hospital, Busan, Korea

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background: The "gold standard" for proper epidural catheter positioning is a clinical response, as assessed by a pinprick test. Yet it may take time or it may be difficult to perform this test after epidural catheter placement in sedated or uncooperative patients or during general anesthesia. We assessed the usefulness of aspirating injected air via an epidural catheter as an indicator of correct epidural catheter placement.
Methods: We surveyed 200 patients who underwent surgery under general or epidural anesthesia. A Tuohy needle was inserted into the epidural space with using the hanging drop technique. After placement of the epidural catheter, 3 ml of air was injected via the catheter, and then the volume of aspirated air was measured.
Results: The mean volume of aspirated air was 2.3 ± 0.7 ml (75% of the injected air volume) and this ranged from 0 to 3 ml.
Conclusions: Aspiration of injected air is a simple alternative method for identifying the appropriate placement of epidural catheters in the epidural space. (Korean J Pain 2009; 22: 124-129)

Keywords: air aspiration, epidural anesthesia, epidural catheter.