Optimal Concentration of Remifentanil for NIM Tube Intubation with Low-dose NMBA

March 15, 2025 updated by: Sung Hye Byun, Kyungpook National University Chilgok Hospital

Optimal Concentration of Remifentanil for Achieving Excellent Intubating Condition During Low-dose Neuromuscular Blocking Agent Administration for Intraoperative Neuromonitoring Using Nerve Integrity Monitoring Tube

During thyroid surgery, Intraoperative Neuromonitoring (IONM) plays a crucial role in preventing serious complications such as bilateral vocal cord paralysis. It achieves this by detecting damage to the recurrent laryngeal nerve (RLN) and predicting the RLN's functional status. The utilization of Nerve Integrity Monitoring tubes (NIM tubes) is on the rise for effective IONM. As IONM relies on observing electromyographic (EMG) responses to direct electrical nerve stimulation, the routine use of neuromuscular blocking agents (NMBAs) in general anesthesia can impact the interpretation of IONM results and potentially reduce sensitivity to nerve responses to stimulation. However, the use of NMBAs is essential for ensuring smooth endotracheal intubation in patients undergoing general anesthesia. Numerous studies suggest that NMBA usage provides superior intubation conditions and reduces vocal cord complications compared to scenarios without NMBA.

Various regimens for neuromuscular blockade methods are employed during IONM in thyroid surgery, ranging from not using NMBAs at all to using a full dose of NMBA for intubation. This is followed by the administration of sugammadex, an NMBA reversal agent, before nerve monitoring. One of the methods known for providing satisfactory intubation conditions while ensuring the quality of EMG signals during IONM in thyroid surgery is using rocuronium at an ED95 dose of 0.3 mg/kg. This approach is considered suitable for most IONM scenarios. However, when adequate muscle relaxation is not achieved, not all patients can undergo intubation, necessitating a strategy for appropriate intubation conditions.

Historically, it has been reported that achieving satisfactory intubation conditions without the use of NMBA during general anesthesia requires higher amounts of propofol and opioids. Therefore, the assumption is made that using remifentanil, an opioid used in total intravenous anesthesia (TIVA), at an appropriate concentration can provide acceptable intubation conditions with minimal NMBA use for patients undergoing IONM.

This study aims to determine the optimal concentration of remifentanil needed to achieve excellent intubation conditions in patients undergoing thyroid surgery with IONM using rocuronium 0.3 mg/kg as the NMBA during TIVA

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

21

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • All female aged 20-60
  • ASA (American Society of Anesthesiologists) physical status I or II
  • who scheduled for thyroidectomy under intraoperative neuromonitoring with a nerve integrity monitoring tube (NIM tube)

Exclusion Criteria:

  • Patients anticipated to experience challenging intubation.
  • Patients who have had an upper respiratory tract infection within the past 2 weeks.
  • Patients with a history of heart, lung, and kidney diseases.
  • Patients with a body mass index (BMI) of 30 kg/m² or higher.
  • Patients currently taking analgesics.
  • Patients expressing a desire not to participate in the study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: N/A
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Remifentanil for NIM tube intubation
Drug: Remifentanil

Following a sequential allocation scheme, the predetermined Ce of remifentanil for each patient will be determined by the Dixon up-and-down method. The Ce of remifentanil for the first patient will be 4.0 ng/ml, and then the remifentanil Ce will be increased or decreased in 0.5 ng/ml increments for subsequent patients depending on the success or failure of intubation.

The Ce of remifentanil to provide acceptable intubation at low dose neuromuscular blockade, the primary outcome, will be determined by obtaining seven crossovers of patients with "acceptable intubation"/"unacceptable intubation" and then calculating the mean of the midpoint doses for each independent pair of patients. According to previous studies that estimated EC50 by Dixon's up-and-down method, 6-8 "failure/success crossover pairs" are required, so this study aims to collect independent data of 7 pairs of "intubation acceptable/unacceptable" patients.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Optimal effect-site concentration (Ce) of remifentanil
Time Frame: During the tracheal intubation
Finding the Ce of remifentanil that provides acceptable condition of tracheal intubation when administering a low-dose NMBA is the aim of the study. The Ce of remifentanil for the first patient is 4.0 ng/ml, and then the Ce is increased or decreased in 0.5 ng/ml increments for subsequent patients depending on the success or failure of intubation. About 3 minutes after administering rocuronium 0.3 mg/kg, NIM tube will be intubated. At this time, the intubation condition will be evaluated using the grading system described by Fuchs-Buder. There are 4 items (jaw relaxation, vocal cord position, cough response, and limb movement) that are evaluated, and a total score can be calculated based on them: 1 point if all items are E, 3 points if even one item is P, and 2 points for the rest. A tracheal intubation condition rating of 1 or 2 indicates that the intubation is acceptable (successful), and a rating of 3 indicates that the intubation is unacceptable (unsuccessful).
During the tracheal intubation

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The rating of each item of the grading system of the tracheal intubation condition
Time Frame: During the tracheal intubation
There are 4 items (jaw relaxation, vocal cord position, cough response, and limb movement) in the grading system described by Fuchs-Buder. We will also evaluate the grade of these items.
During the tracheal intubation
Total dose of remifentanil administered until tracheal intubation
Time Frame: From the start of the anesthesia induction to tracheal intubation
From the start of the anesthesia induction to tracheal intubation
Incidence of hypotension and bradycardia
Time Frame: From the start of the anesthesia induction to tracheal intubation
From the start of the anesthesia induction to tracheal intubation
Doses of agents (ephedrine and atropine) administered to treat hypotension and bradycardia
Time Frame: From the start of the anesthesia induction to tracheal intubation
From the start of the anesthesia induction to tracheal intubation

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Kyungpook National University Chilgok Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 20, 2023

Primary Completion (Actual)

March 10, 2024

Study Completion (Actual)

March 20, 2024

Study Registration Dates

First Submitted

November 20, 2023

First Submitted That Met QC Criteria

November 29, 2023

First Posted (Actual)

December 8, 2023

Study Record Updates

Last Update Posted (Actual)

March 25, 2025

Last Update Submitted That Met QC Criteria

March 15, 2025

Last Verified

March 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • KNUCH 2023-10-033

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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