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Tsui Test as a Predictor of Bupivacaine Consumption in Labour Epidurals

This study has been completed.
Information provided by:
Samuel Lunenfeld Research Institute, Mount Sinai Hospital Identifier:
First received: November 13, 2008
Last updated: March 25, 2010
Last verified: March 2010
Low current electrical stimulation test, also called the Tsui test, has been used successfully to confirm the catheter location in the epidural space in various patient populations. The results of this study will show whether or not doing a Tsui test can predict inadequate epidural analgesia early in the course of placing the epidural, so that the appropriate measures could be applied immediately upon gathering unfavorable results.

Condition Intervention
Pain Procedure: Tsui test

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Diagnostic
Official Title: Tsui Test as a Predictor of Bupivacaine Consumption in Labour Epidurals

Resource links provided by NLM:

Further study details as provided by Samuel Lunenfeld Research Institute, Mount Sinai Hospital:

Primary Outcome Measures:
  • Consumption of bupivacaine in mg/hour in the first 2 hours of epidural anesthesia [ Time Frame: 2 hours ]

Secondary Outcome Measures:
  • Incidence of inadequate epidural block. [ Time Frame: 2 hours ]
  • Current (mA) needed to elicit motor response; 1. before test dose and 2. 5 minutes after test dose. [ Time Frame: 5 minutes ]
  • Contraction pattern elicited by the Tsui test at baseline and after test dose. [ Time Frame: 5 minutes ]

Enrollment: 102
Study Start Date: November 2008
Study Completion Date: August 2009
Primary Completion Date: August 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Tsui test
Tsui test administration.
Procedure: Tsui test
The stimulator is set at frequency of 1Hz with 200ms pulse width and the current output ranging from 0 to 20 mA. The current output will be carefully increased from zero until motor activity is detected up to a maximum of 20 mA.

Detailed Description:

Despite its very high success rate, the epidural technique remains a rather blind technique, and failures continue to occur. The incidence and reasons for failure are not well understood. The Tsui test is not routinely performed with each epidural catheter insertion, but rather it is used when there is suspicion about the catheter location.

In this study, the Tsui test will be performed twice during the epidural procedure, and bupivacaine consumption will be recorded for the first 2 hours.

Information gained from this study could have great impact in clinical practice, since the incidence of inadequate labor analgesia is still relatively high (10-20%), leading to maternal distress and disappointing labor experience.


Ages Eligible for Study:   18 Years to 50 Years   (Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Women over 18 years of age requesting an epidural for labor and delivery
  • Cervix dilated 0-5 cm and pain VAS>6
  • Able to communicate in English
  • Informed consent

Exclusion Criteria:

  • Refusal to provide written informed consent
  • Patients unable to communicate in English
  • Contraindication to regional anesthesia
  • Allergy or hypersensitivity to lidocaine, bupivacaine or fentanyl
  • Sedatives or opioids received prior to insertion of epidural catheter
  • Abnormal vertebral anatomy, such as previous spine surgery and scoliosis
  • Coexisting neurological disorders
  • Patients with implanted electronic devices
  Contacts and Locations
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Please refer to this study by its identifier: NCT00792311

Canada, Ontario
Mount Sinai Hospital
Toronto, Ontario, Canada, M5G 1X5
Sponsors and Collaborators
Samuel Lunenfeld Research Institute, Mount Sinai Hospital
Principal Investigator: Jose CA Carvalho, MD Mount Sinai Hospital, New York
  More Information

Responsible Party: Dr. Jose C.A. Carvalho, Mount Sinai Hospital Identifier: NCT00792311     History of Changes
Other Study ID Numbers: 08-02
Study First Received: November 13, 2008
Last Updated: March 25, 2010

Keywords provided by Samuel Lunenfeld Research Institute, Mount Sinai Hospital:
Tsui test
Epidural Analgesia

Additional relevant MeSH terms:
Anesthetics, Local
Central Nervous System Depressants
Physiological Effects of Drugs
Sensory System Agents
Peripheral Nervous System Agents processed this record on September 19, 2017