Epidural electrical stimulation test versus local anesthetic test dose for thoracic epidural catheter placement: a prospective observational study

Abstract

Purpose This study examined the concordance between epidural electrical stimulation test (EEST) and local anesthetic (LA) test dose to indicate correct thoracic epidural catheter position. The relationship between the test results and epidural postoperative analgesia was also assessed. Methods This prospective observational cohort study was done in patients receiving thoracic epidural analgesia for abdominal surgery. After insertion, the epidural catheter was tested using a nerve stimulator to elicit a motor response. The LA test dose was then administered, and sensory block to ice and pinprick was assessed. The primary outcome was the presence/absence of motor response to EEST and sensory block to test dose. Concordance of responses was assessed using kappa statistics, and their predictive power of postoperative epidural analgesia was evaluated.

Determination of thoracic epidural catheter placement: electrical epidural stimulation (Tsui test) is simple, effective, and under-utilized

“…It is essential to create a continuous column of conducting fluid within the stainless-steel wire-reinforced epidural catheter by priming it with saline after insertion and to ensure that there is no air within the system. 3 We have found that application of gentle continuous pressure on the saline column during stimulation facilitates a reliable and repeatable evoked motor response. It is notable that most studies evaluating the test do not use a stimulating catheter.…”

“…Though the adoption of the EEST in adults appears to be quite slow, the clinical need to decrease thoracic epidural block failure is well documented. We hope that the study by Balki et al 3 will remind clinicians that the EEST is a superior option when objective confirmation of epidural catheter positioning is sought. We are confident that routine adoption of the EEST will help to maximize the benefits derived from epidural analgesia.…”

“…1,2 This speaks to the difficulty of assessing correct catheter placement in the epidural space that directly relates to its function. Bearing this in mind, we were pleased to read the article in this issue of the Journal, by Balki et al, 3 which compared the agreement between the responses with a standard local anesthetic test dose and with the epidural electrical stimulation test (EEST) in patients undergoing abdominal surgery. The study demonstrated that the EEST is a sensitive and effective test for confirming the correct position of a thoracic epidural catheter, which relates to its ability to provide adequate postoperative epidural analgesia.…”

“…It is notable that most studies evaluating the test do not use a stimulating catheter. [3][4][5] If using a stimulating epidural catheter, saline priming is not required. 20 The EEST has been criticized for its inability to identify a catheter tip located in the paravertebral space.…”

“…Il est indispensable de créer une colonne continue de liquide conducteur dans le cathéter péridural en l'amorçant avec du salin après son insertion et de s'assurer qu'il n'y a pas d'air dans le système. 3 Nous avons constaté que l'application d'une pression continue douce sur la colonne de salin au cours de la stimulation facilite une réponse motrice évoquée fiable et répétable. À noter que la majorité des études évaluant le test n'utilisent pas un cathéter de stimulation.…”