Ultrasound-Based Airway Assessment for Predicting Difficult Intubation in Adult Female Patients (USG-AIRWAY)

Diagnostic Performance of Ultrasonographic Airway Measurements for Predicting Difficult Intubation in Adult Female Patients: A Prospective Observational Study

This prospective observational study aims to evaluate the ability of selected ultrasonographic airway measurements to predict difficult intubation in adult female patients undergoing elective surgery. Pre-induction airway ultrasonography will be performed to measure tongue thickness and anterior neck soft tissue-related parameters. These measurements will be compared with laryngoscopic findings during direct laryngoscopy. The results of this study may help identify practical and reliable ultrasound-based markers for preoperative airway assessment and improve patient safety.

Study Overview

• Status: Completed
• Conditions: Difficult Intubation; Airway Assessment

Detailed Description

This is a prospective, single-center observational study conducted in adult female patients scheduled for elective surgery under general anesthesia. The study was performed at the University of Health Sciences Adana City Training and Research Hospital after approval by the institutional ethics committee.

Before induction of anesthesia, standardized ultrasonographic airway assessments were performed by an experienced anesthesiologist. Measurements included tongue thickness, the distance from the skin to the anterior commissure of the vocal cords, the distance from the skin to the hyoid bone, and the distance from the skin to the epiglottis. All measurements were obtained under static pre-induction conditions using portable ultrasound equipment.

Following anesthesia induction, direct laryngoscopy was performed, and laryngoscopic view was graded according to the Cormack-Lehane classification. Difficult intubation was defined based on predefined laryngoscopic criteria. Ultrasonographic measurements were then analyzed for their diagnostic performance in predicting difficult intubation.

The primary objective of the study was to determine the most informative ultrasonographic parameter for predicting difficult intubation in this population. Secondary objectives included comparing the relative diagnostic value of different ultrasound measurements and evaluating their potential role in routine preoperative airway assessment.

• Study Type: Observational
• Enrollment (Actual): 400

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Adana
    • Adana, Adana, Turkey (Türkiye), 010650
      • Adana City Training and Research Hospital

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Adult female patients aged 18-65 years undergoing elective surgery under general anesthesia at a tertiary care hospital. Participants were non-pregnant and scheduled for non-emergency procedures.

Description

Inclusion Criteria:

• Female patients aged 18-65 years
• American Society of Anesthesiologists (ASA) physical status I-III physical status I-III
• Scheduled for elective surgery under general anesthesia requiring tracheal intubation
• Ability to provide informed consent

Exclusion Criteria:

• Body mass index ≥30 kg/m²
• Known history of difficult intubation
• Anatomical airway abnormalities or head and neck pathology
• Pregnancy
• Emergency surgery

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Airway Ultrasound Assessment Cohort; Adult female patients undergoing elective surgery in whom preoperative airway ultrasonography was performed for observational assessment of airway anatomy. No intervention was assigned as part of the study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Difficult Intubation	Difficult intubation defined as Cormack-Lehane grade III or IV and/or the need for additional airway devices or techniques during tracheal intubation.	Perioperative

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ultrasonographic Measurement of Tongue Thickness	Preoperative ultrasonographic measurement of tongue thickness performed in the suprahyoid region.	Preoperative assessment
Ultrasonographic Measurement of Skin-to-Hyoid Bone Distance	Preoperative ultrasonographic measurement of the distance between the skin and the hyoid bone.	Preoperative assessment
Ultrasonographic Measurement of Skin-to-Epiglottis Distance	Preoperative ultrasonographic measurement of the distance between the skin and the epiglottis.	Preoperative assessment
Ultrasonographic Measurement of Distance from Skin to Anterior Commissure of the Vocal Cords	Preoperative ultrasonographic measurement of the distance from the skin to the anterior commissure of the vocal cords.	Preoperative assessment

Collaborators and Investigators

• Sponsor: Adana City Training and Research Hospital

Study record dates

Study Major Dates

• Study Start (Actual): May 15, 2025
• Primary Completion (Actual): December 15, 2025
• Study Completion (Actual): December 15, 2025

Study Registration Dates

• First Submitted: December 29, 2025
• First Submitted That Met QC Criteria: January 8, 2026
• First Posted (Actual): January 15, 2026

Study Record Updates

• Last Update Posted (Actual): January 15, 2026
• Last Update Submitted That Met QC Criteria: January 8, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Difficult Airway; Airway Ultrasound; Tongue Thickness
• Other Study ID Numbers: ADN-USG-AIRWAY-2025

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