Airway Ultrasound vs Clinical Predictors for Difficult Airway

Tokat Gaziosmanpasa University

Status: Not yet enrolling

Conditions: Preoperative Evaluation; Ultrasonography; Difficult Airway

Study type: Observational

Funder types: Other

Identifiers

NCT07243106

25-MOBAEK-329

Details and patient eligibility

About

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.

Full description

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).

Enrollment: 140 estimated patients

Sex: All

Ages: 18 to 60 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

140 participants in 1 patient group

Adult patients scheduled for elective surgery under general anesthesia with endotracheal intubation

Description:

Demographic data of all participants-including age, sex, type of planned surgery, ASA physical status, and comorbidities-will be recorded. Before induction of anesthesia, all patients will be evaluated using standard clinical airway assessment parameters. These include the Mallampati score, thyromental distance, sternomental distance, neck circumference, and upper lip bite test. Body mass index (BMI) and waist-to-hip ratio will also be measured and documented. In the preoperative period, all patients will undergo airway ultrasonography performed by an anesthesiologist. Sonographic assessments will be carried out by a single experienced anesthesiologist using a linear transducer, with the patient positioned in the sniffing position. The following ultrasound measurements will be obtained and recorded: Skin-to-epiglottis distance, skin-to-hyoid bone distance, skin-to-anterior commissure of the vocal cords distance, skin-to-trachea distance at the suprasternal notch level.