TMH And Ultrasound For Difficult Airway Prediction (TMH-USG)

Comparative Evaluation Of Thyromental Height And Ultrasonographic Airway Measurements In Predicting Difficult Airway: A Prospective Observational Study

This prospective observational study aims to evaluate the predictive value of thyromental height (TMH) and ultrasonographic airway measurements in predicting difficult airway in adult patients undergoing elective surgery under general anesthesia.

Preoperative airway assessment will include standard clinical evaluation, TMH measurement, and ultrasonographic measurements of anterior neck soft tissue. Perioperative airway management data, including intubation difficulty, number of attempts, and Cormack-Lehane classification, will be recorded.

The relationship between preoperative measurements and difficult airway will be analyzed to determine their predictive accuracy and clinical usefulness.

Study Overview

• Status: Not yet recruiting
• Conditions: Airway Management; Difficult Airway

Detailed Description

Difficult airway management remains a critical issue in anesthetic practice, associated with significant morbidity and mortality. Traditional clinical airway assessment methods have limited sensitivity and specificity in predicting difficult airway. Recently, thyromental height (TMH) and ultrasonographic airway measurements have been proposed as promising tools for improving prediction accuracy.

This prospective, single-center observational study will be conducted in adult patients undergoing elective surgery under general anesthesia. Patients aged 18 years and older with ASA physical status I-III will be included.

Preoperative evaluation will include standard airway assessment methods such as Mallampati score, mouth opening, sternomental distance, and thyromental distance. In addition, TMH will be measured, and ultrasonographic measurements of anterior neck soft tissues will be performed, including skin-to-epiglottis distance, pretracheal soft tissue thickness, and hyomental distance.

Perioperative airway management data will be recorded, including Cormack-Lehane classification, number of intubation attempts, use of adjunct airway devices, and intubation difficulty score.

The primary objective is to evaluate the predictive value of TMH and ultrasonographic measurements for difficult airway. Secondary objectives include assessing their relationship with intubation difficulty, number of attempts, and airway-related complications.

The findings of this study are expected to contribute to improved preoperative airway assessment and safer airway management strategies in clinical practice.

• Study Type: Observational
• Enrollment (Estimated): 240

Contacts and Locations

• Study Contact: Name: Serra Topal, MD; Phone Number: 05068823855; Email: dr.serra@msn.com

Study Locations

• Turkey (Türkiye)
  • Nilüfer
    • Bursa, Nilüfer, Turkey (Türkiye), 16110
      • Bursa City Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adult patients undergoing elective surgical procedures under general anesthesia at a tertiary care hospital will be prospectively enrolled. All participants will undergo standardized preoperative airway assessment, including thyromental height measurement and ultrasonographic airway evaluation, followed by perioperative airway management assessment.

Description

Inclusion Criteria:

Adult patients aged 18 years and older Patients scheduled for elective surgery under general anesthesia Patients requiring endotracheal intubation Patients who provide written informed consent

Exclusion Criteria:

• Patients with known upper airway pathology (e.g., tumor, trauma, infection) Patients with previous head and neck surgery or anatomical deformity affecting airway evaluation Patients with limited mouth opening (<3 cm) or severe cervical spine restriction Patients with contraindications to ultrasonographic examination Patients requiring rapid sequence induction or emergency surgery Patients who refuse to participate

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Airway Assessment Cohort; Adult patients undergoing elective surgery under general anesthesia will be included. All participants will undergo standard preoperative airway assessment, including thyromental height (TMH) measurement and ultrasonographic airway evaluation. Intraoperative airway management and intubation-related parameters will be recorded to assess the predictive value of TMH and ultrasound measurements for difficult airway.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prediction of Difficult Intubation	The primary outcome is the ability of thyromental height (TMH) and ultrasonographic airway measurements to predict difficult intubation. Difficult intubation will be defined as Cormack-Lehane grade ≥3, requirement of multiple intubation attempts, or use of advanced airway devices.	During induction of anesthesia (intraoperative period)

Collaborators and Investigators

• Sponsor: Bursa City Hospital
• Collaborators: Emre ULUSOY

Study record dates

Study Major Dates

• Study Start (Estimated): May 15, 2026
• Primary Completion (Estimated): May 15, 2027
• Study Completion (Estimated): May 15, 2027

Study Registration Dates

• First Submitted: April 13, 2026
• First Submitted That Met QC Criteria: April 17, 2026
• First Posted (Actual): April 23, 2026

Study Record Updates

• Last Update Posted (Actual): April 23, 2026
• Last Update Submitted That Met QC Criteria: April 17, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Difficult Intubation; Cormack-Lehane; Airway Ultrasound; Thyromental Height
• Other Study ID Numbers: TMH-USG-2026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data (IPD) will not be shared due to institutional policies and protection of patient confidentiality.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No