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

  • Mrinalini BalkiEmail author
  • Archana Malavade
  • Xiang Y. Ye
  • Umamaheswary Tharmaratnam
Reports of Original Investigations



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.


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.


Sixty-eight thoracic epidural catheters were inserted, of which 62 were used perioperatively. The kappa agreement between EEST and LA test dose responses was moderate at 0.42 (95% confidence interval [CI], 0.18 to 0.67). Positive responses to EEST and LA test dose were observed in 62 (100%) and 50 (81%) patients, respectively, while 52 patients (84%) showed adequate analgesia postoperatively. The sensitivity (95% CI) of EEST and LA test dose to predict adequate postoperative epidural analgesia was 1 (0.93 to 1) and 0.79 (0.65 to 0.89), respectively, and the positive predictive values (95% CI) of EEST and LA test dose were 0.84 (0.75 to 0.93) and 0.82 (0.71 to 0.92), respectively.


Following thoracic epidural catheter insertion, the responses to the EEST and LA test dose showed “moderate” agreement. The EEST has a higher sensitivity than the LA test dose to predict adequate epidural analgesia following abdominal surgery, however, both tests have a comparable positive predictive value.

Test de stimulation électrique péridurale contre test dose d’anesthésie locale pour la vérification du positionnement d’un cathéter péridural thoracique: étude observationnelle prospective



Cette étude a porté sur la concordance entre le test de stimulation électrique péridurale (EEST) et le test par une dose d’anesthésique local (AL) pour indiquer la position adéquate d’un cathéter thoracique. La relation entre les résultats des tests et l’analgésie péridurale postopératoire a également été évaluée.


Cette étude de cohorte observationnelle prospective a été menée chez des patients recevant une analgésie péridurale thoracique pour chirurgie abdominale. Après insertion, le cathéter épidural a été testé au moyen d’un stimulateur nerveux pour déclencher une réponse motrice. La dose test d’AL a alors été administrée et le blocage sensitif à la glace et aux piqûres a été évalué. Le critère d’évaluation principal était la présence ou l’absence de réponse motrice à l’EEST et au blocage sensitif à la dose test. La concordance des réponses a été évaluée au moyen de statistiques kappa et leur prédiction de l’efficacité de l’analgésie péridurale postopératoire a été évaluée.


Soixante-huit cathéters périduraux thoraciques ont été insérés parmi lesquels 62 ont été utilisés en périopératoire. La concordance kappa entre les réponses à l’EEST et à la dose test d’AL a été modérée : 0,42 (intervalle de confiance [IC] à 95 %, 0,18 à 0,67). Les réponses positives à l’EEST et à la dose test d’AL ont été observées chez respectivement 62 (100 %) et 50 (81 %) patients, tandis que 52 patients (84 %) ont présenté une analgésie postopératoire adéquate. La sensibilité (IC à 95 %) de l’EEST et de la dose test d’AL pour la prédiction de l’analgésie péridurale postopératoire a été, respectivement, de 1 (0,93 à 1) et 0,79 (0,65 à 0,89) et les valeurs prédictives positives (IC à 95 %) de l’EEST et de la dose test d’AL ont été, respectivement, de 0,84 (0,75 à 0,93) et 0,82 (0,71 à 0,92).


Après insertion d’un cathéter péridural thoracique, la concordance entre l’EEST et la dose test d’AL s’est avérée « modérée ». La sensibilité de l’EEST pour la prédiction d’une analgésie péridurale adéquate après chirurgie abdominale est supérieure à celle de la dose test d’AL; toutefois les deux tests ont des valeurs prédictives positives comparables.



We would like to thank Ms. Kristi Downey, Anesthesia Research Coordinator, Mount Sinai Hospital for creating a database for the study and Dr. Devdatta Desai, Anesthesia fellow, Mount Sinai Hospital, for assisting with the initial study planning.

Conflicts of interest

The authors have no conflicts of interest.

Editorial responsibility

This submission was handled by Dr. Steven Backman, Associate Editor, Canadian Journal of Anesthesia.

Author contributions

Mrinalini Balki contributed substantially to all aspects of this manuscript, including study conception and design, acquisition, analysis, and interpretation of data, and drafting the article. Archana Malavade contributed substantially to the acquisition, analysis, and interpretation of data, and revision of the article. Xiang Y. Ye contributed substantially to the conception and design, analysis, and interpretation of data, and revision of the article. Uma Tharmaratnam contributed substantially to conception and design; acquisition, analysis, and interpretation of data, and revision of the article.


Mrinalini Balki was supported by Merit awards, Department of Anesthesia, University of Toronto, Canada. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.


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Copyright information

© Canadian Anesthesiologists' Society 2019

Authors and Affiliations

  • Mrinalini Balki
    • 1
    • 2
    • 3
    Email author
  • Archana Malavade
    • 1
  • Xiang Y. Ye
    • 4
  • Umamaheswary Tharmaratnam
    • 1
  1. 1.Department of Anesthesia and Pain Management, Mount Sinai HospitalUniversity of TorontoTorontoCanada
  2. 2.Department of Obstetrics and Gynaecology, Mount Sinai HospitalUniversity of TorontoTorontoCanada
  3. 3.Lunenfeld-Tanenbaum Research InstituteSinai Health SystemTorontoCanada
  4. 4.Micare Research Centre, Mount Sinai HospitalUniversity of TorontoTorontoCanada

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