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Enrolling by Invitation

NCT Number: NCT07243106

Airway Ultrasound vs Clinical Predictors for Difficult Airway

This prospective observational study aims to evaluate the diagnostic value of airway ultrasonography in predicting difficult intubation in adult patients undergoing elective surgery under general anesthesia. Preoperative sonographic measurements of upper airway structures will be compared with conventional clinical airway assessment parameters such as the Mallampati score, thyromental distance, and sternomental distance.

The study seeks to determine whether ultrasonographic measurements can serve as independent predictors of difficult airway and whether combining them with clinical parameters improves diagnostic accuracy. Additionally, the correlation between sonographic findings and the Intubation Difficulty Scale (IDS) will be analyzed to assess the potential clinical utility of airway ultrasound in preoperative airway evaluation.

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Key information

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Tokat Gaziosmanpasa University

Tokat Province, 60100, Turkey (Türkiye)

About this study

Airway management is one of the most critical and potentially life-threatening procedures in anesthesiology practice. Difficult intubation may result in severe morbidity and mortality if not promptly and effectively managed. Therefore, reliable preoperative prediction of a difficult airway is crucial for ensuring patient safety and optimizing perioperative outcomes.

Traditional clinical assessment methods-such as the Mallampati classification, thyromental distance, and sternomental distance-are commonly used to predict difficult airway. However, these predictors have limited sensitivity and specificity, and their diagnostic accuracy may vary depending on operator experience and subjective interpretation.

In recent years, ultrasonography has gained increasing acceptance in anesthesiology as a non-invasive, rapid, inexpensive, and real-time imaging technique. Airway ultrasonography enables direct visualization of individual anatomical variations in the upper airway, providing more objective and reproducible data for airway assessment.

The primary objective of this study is to determine the diagnostic performance of ultrasonographic parameters obtained from preoperative airway ultrasound in predicting difficult laryngoscopy and intubation, and to compare them with conventional clinical assessment methods. The study will also evaluate whether ultrasonographic measurements are independent predictors of difficult airway and whether combining sonographic and clinical parameters enhances overall diagnostic accuracy.

Furthermore, the relationship between ultrasound-based anatomical measurements and the Intubation Difficulty Scale (IDS) will be analyzed. This correlation aims to demonstrate the potential contribution of airway ultrasonography to clinical decision-making and its possible role in improving airway safety in anesthetic practice.

Hypotheses:

H0 (Null Hypothesis): Airway ultrasonography does not provide higher diagnostic accuracy than traditional clinical assessment methods in predicting difficult intubation and has no significant correlation with the Intubation Difficulty Scale (IDS).

H1 (Alternative Hypothesis): Airway ultrasonography provides higher diagnostic accuracy than traditional clinical assessment methods in predicting difficult intubation and is significantly correlated with the Intubation Difficulty Scale (IDS).

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adult patients aged 18-60 years
  • Scheduled for elective surgery
  • ASA (American Society of Anesthesiologists) physical status I, II, or III
  • Planned for endotracheal intubation under general anesthesia

Exclusion criteria

  • Patients requiring emergency surgery
  • Patients with a known history of difficult intubation
  • Patients with head or neck trauma
  • Patients with a history of previous head or neck surgery or head/neck malignancy
  • Pregnant patients

Treatment and study plan

Primary outcomes

  1. The Intubation Difficulty Scale (IDS)

    Time frame: During tracheal intubation (approximately 1-3 minutes after induction of anesthesia)

    The Intubation Difficulty Scale (IDS) is a quantitative scoring system used to objectively assess the complexity of tracheal intubation. It incorporates seven parameters: number of intubation attempts, number of operators, number of alternative techniques used, Cormack-Lehane grade, lifting force required, necessity of external laryngeal pressure, and position of the vocal cords.

    The total IDS score is calculated as the sum of these variables, providing a numerical indicator of intubation difficulty (IDS = 0 indicates easy intubation; IDS = 1-5 mild to moderate difficulty; IDS > 5 difficult intubation).

  2. Difficulty of mask ventilation

    Time frame: During 2-minute face mask ventilation after induction of anesthesia

    After standard induction of anesthesia, all patients will be ventilated via face mask for 2 minutes, followed by tracheal intubation using a Macintosh laryngoscope. The difficulty of mask ventilation will be assessed using the Han Mask Ventilation Scale, defined as follows:

    Class 1: Mask ventilation possible

    Class 2: Mask ventilation possible with the use of an oral airway or other adjuncts

    Class 3: Mask ventilation possible only with the assistance of a second person

    Class 4: Mask ventilation impossible

Sponsors and collaborators

Lead sponsor

Tokat Gaziosmanpasa University

Other

Registry information

Official study title

Role of Airway Ultrasonography in Predicting Difficult Airway: Comparison of Clinical and Sonographic Parameters

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Nov 21, 2025
Registry last updated
Jul 1, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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