Dex vs SLNB in Spontaneous Breathing Via THRIVE for Laryngeal Surgery

September 5, 2025 updated by: Yuan-Yi Chia, Kaohsiung Veterans General Hospital.

Comparison of Dexmedetomidine and Superior Laryngeal Nerve Block for Non-Intubated Endoscopic Laryngeal Surgery With Spontaneous Breathing Using Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE): A Randomized Controlled Trial

This prospective, randomized controlled trial evaluated the efficacy and safety of two anesthetic strategies-dexmedetomidine infusion and ultrasound-guided superior laryngeal nerve block (SLNB)-in patients undergoing non-intubated endoscopic laryngeal surgery under spontaneous breathing supported by Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE). The primary outcome was the arterial partial pressure of carbon dioxide (PaCO₂), measured at three time points: before oxygenation, at the end of surgery, and in the post-anesthesia care unit (PACU). Secondary outcomes included other arterial blood gas parameters, hemodynamic variables, and surgeon satisfaction scores.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Detailed Description:

This prospective, single-center randomized controlled trial was conducted to compare two anesthetic strategies-Dexmedetomidine infusion and ultrasound-guided bilateral superior laryngeal nerve block (SLNB)-for non-intubated endoscopic laryngeal surgery performed under spontaneous respiration with high-flow nasal oxygenation (THRIVE). The study was carried out at Kaohsiung Veterans General Hospital, Taiwan.

Patients aged 20 to 80 years scheduled for elective microlaryngeal surgery were enrolled and randomly assigned to either the Dexmedetomidine (Dex) group or the SLNB group. Both groups received total intravenous anesthesia (TIVA) with propofol and oxygenation via transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) to facilitate tubeless anesthesia. The Dex group received a loading dose of Dexmedetomidine (1 µg/kg over 10 minutes) followed by continuous infusion (1 µg/kg/h), while the SLNB group underwent bilateral ultrasound-guided nerve blocks with 1% lidocaine.

The primary outcome was the arterial partial pressure of carbon dioxide (PaCO₂) measured at three time points: before oxygenation (baseline), at the end of surgery, and 15 minutes after arrival in the post-anesthesia care unit (PACU). Secondary outcomes included arterial blood gas parameters (PaO₂, pH), intraoperative hemodynamic variables (HR, SBP, DBP, MAP), and surgeon satisfaction scores.

The goal of this study was to evaluate whether Dexmedetomidine, which offers both sedative and analgesic properties while preserving spontaneous breathing, could serve as a viable alternative to regional nerve block in the context of shared-airway surgery. Particular attention was given to the risk of carbon dioxide accumulation and respiratory acidosis associated with Dexmedetomidine.

This trial provides important insights into the safety and efficacy of two distinct anesthetic modalities for performing non-intubated endoscopic laryngeal surgery and contributes to the ongoing optimization of airway management strategies in tubeless anesthesia.

Study Type

Interventional

Enrollment (Actual)

46

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

  • Taiwan
    • Taiwan
      • Kaohsiung, Taiwan, Taiwan, 81362
        • Kaohsiung Veterans General Hospital

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

20 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Subjects are between 20-80 years old.
  • Patients undergoing endoscopic laryngeal surgery.
  • Anesthesiologists rated ASA as between I and III.

Exclusion Criteria:

  • Having drug dependence and drinking habits.
  • Abnormal heart, liver and kidney function.
  • Allergic reactions to narcotic drugs.
  • Emergency surgery.
  • pregnancy.
  • Refuse to participate.
  • BMI ≥ 35 kg/m2.

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Dexmedetomidine Infusion Arm for Non-Intubated Laryngeal Surgery Using THRIVE
This arm involves patients undergoing endoscopic laryngeal surgery under non-intubated general anesthesia with spontaneous breathing, supported by transnasal humidified rapid-insufflation ventilatory exchange (THRIVE). Patients receive an intravenous loading dose of dexmedetomidine (1 µg/kg over 10 minutes), followed by a continuous infusion (1 µg/kg/h) for sedation and analgesia. No regional nerve blocks are performed in this arm. Supplemental propofol is titrated via target-controlled infusion (TCI) to maintain BIS levels between 40-60. Topical 10% lidocaine is applied to the airway before insertion of the laryngoscope. Intraoperative fentanyl may be given as needed based on hemodynamic responses.
Drug: Dexmetedomedine infusion
Patients received a loading dose of dexmedetomidine at 1 µg/kg over 10 minutes, followed by a continuous infusion at 1 µg/kg/h throughout the procedure. This regimen was combined with TIVA (propofol) and THRIVE to support spontaneous breathing during endoscopic laryngeal surgery.
Active Comparator: Superior Laryngeal Nerve Block (SLNB)
This arm includes patients undergoing non-intubated endoscopic laryngeal surgery with spontaneous breathing, supported by transnasal humidified rapid-insufflation ventilatory exchange (THRIVE). After induction with propofol (via TCI) and standard premedication, bilateral ultrasound-guided superior laryngeal nerve blocks are performed using 5 mL of 1% lidocaine on each side for regional analgesia. No dexmedetomidine is administered in this group. Anesthesia is maintained with propofol titrated to a BIS range of 40-60. Additional fentanyl may be administered intraoperatively as needed to control sympathetic responses. Topical 10% lidocaine is applied to the airway prior to laryngoscope insertion.
Procedure: Ultrasound-Guided Superior Laryngeal Nerve Block (SLNB)
Following anesthesia induction, patients received bilateral ultrasound-guided superior laryngeal nerve blocks using 5 mL of 1% lidocaine per side. This intervention was combined with total intravenous anesthesia (TIVA) using propofol and high-flow nasal oxygenation (THRIVE) to maintain spontaneous respiration during endoscopic laryngeal surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Perioperative PaCO2
Time Frame: From pre-induction through 15 minutes postoperatively

Arterial blood gas was collected and analyzed at three time points to assess changes in PaCO₂ as the primary outcome:

  1. At baseline (after preoxygenation, prior to induction)
  2. Immediately after completion of endoscopic laryngeal surgery
  3. Fifteen minutes after arrival in the post-anesthesia care unit (PACU)
From pre-induction through 15 minutes postoperatively

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Arterial Oxygenation (PaO₂)
Time Frame: From pre-induction through 15 minutes postoperatively
Arterial partial pressure of oxygen (PaO₂) measured via ABG at three time points: preoxygenation baseline, immediately post-surgery, and 15 minutes after PACU arrival.
From pre-induction through 15 minutes postoperatively
Mean Arterial Pressure (MAP)
Time Frame: Preoperative, intraoperative (every 5 minutes), and 15 minutes postoperatively in the PACU
Monitoring of mean arterial pressure at defined intervals to evaluate cardiovascular responses to anesthetic strategy.
Preoperative, intraoperative (every 5 minutes), and 15 minutes postoperatively in the PACU
Heart rate
Time Frame: Preoperative, intraoperative (every 5 minutes), and 15 minutes postoperatively in the PACU
Assessment of heart rate variability across the surgical timeline to monitor hemodynamic stability.
Preoperative, intraoperative (every 5 minutes), and 15 minutes postoperatively in the PACU
Surgeon stress score
Time Frame: Immediately after completion of the surgical procedure

Subjective evaluation of the surgeon's intraoperative stress level, based on surgical field visibility, patient movement, and anesthetic stability. The score is rated on a 6-point scale from 0 to 5, where:

0 = No stress

  1. = Minimal stress
  2. = Mild stress
  3. = Moderate stress
  4. = High stress
  5. = Extremely high stress
Immediately after completion of the surgical procedure
Arterial pH
Time Frame: Baseline, end of surgery, PACU (15 minutes post-arrival)

Arterial pH will be measured at three time points:

  1. preoxygenation (baseline),
  2. immediately after the end of endoscopic laryngeal surgery,
  3. 15 minutes after arrival in the post-anesthesia care unit (PACU).
Baseline, end of surgery, PACU (15 minutes post-arrival)

Collaborators and Investigators

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

Sponsor

Kaohsiung Veterans General Hospital.

Investigators

  • Study Director: Ting Shou Chang, physician, Kaohsiung Veterans General Hospital.
  • Study Chair: Chih Chi Tsai, RA, Kaohsiung Veterans General Hospital.
  • Study Director: Kai Wei Hsieh, physician, Kaohsiung Veterans General 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 29, 2022

Primary Completion (Actual)

July 31, 2025

Study Completion (Actual)

July 31, 2025

Study Registration Dates

First Submitted

October 4, 2022

First Submitted That Met QC Criteria

October 12, 2022

First Posted (Actual)

October 14, 2022

Study Record Updates

Last Update Posted (Estimated)

September 8, 2025

Last Update Submitted That Met QC Criteria

September 5, 2025

Last Verified

September 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • KSVGH22-CT8-38

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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