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A Dual-chambered Syringe that Allows Identification of the Epidural Space Using the Loss of Resistance Technique with Air and with Saline
  1. Kenneth D. Candido, M.D.* and
  2. Alon P. Winnie, M.D.**
  1. *From the Departments of Anesthesiology, Lenox Hill Hospital, New York, New York, and the
  2. **Pain Control Center, University of Illinois College of Medicine at Chicago.
  1. Address correspondence to Alon P. Winnie, M.D., Pain Control Center (M/C 845), University of Illinois Hospital, 840 S. Wood St., Chicago, IL 60612.


Background and Objectives. Each of the two most widely used techniques for identification of the epidural space, the loss of resistance technique with air and the loss of resistance technique with liquid, has certain advantages and disadvantages. A new syringe is described that has two chambers, one to contain air and the other to contain liquid, to combine the advantages of air with the advantages of liquid and to prevent the disadvantages of each.

Methods. Twenty consecutive adult patients scheduled to receive epidural injections for surgery, obstetrics, or pain control were selected for study. This was an open study, and the EpIdent syringe was used as the only means of identifying the epidural space in every case.

Results. The EpIdent syringe easily and effectively identified the epidural space in all of the patients, with no adverse or unpleasant side effects. Successful identification of the space was documented by the production of adequate anesthesia after the injection of an appropriate volume or local anesthetic. There were no complications.

Conclusions. The successful use of the EpIdent syringe in this preliminary study of 20 patients indicates that it provides a simple, safe, and effective means of identifying the epidural space. It allows the use of a plastic syringe (instead of glass) and avoids the unpleasant or untoward effects associated with currently used loss of resistance techniques.

  • Epidural anesthesia
  • techniques
  • loss of resistance with air
  • loss of resistance with liquid.

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