Evaluation of Anterior Neck Ultrasound in Predicting Difficult Airway in Obese Patients

Ultrasound Assessment of Anterior Neck Soft Tissue Thickness to Predict Difficult Airway Risk in Obese Patients Undergoing for Surgery Under General Anesthesia: an Observational Study

Obese patients are at increased risk of difficult airway management due to anatomical changes in the anterior neck soft tissues. Accurate preoperative prediction of difficult airway remains challenging using conventional clinical airway assessment tests alone.

This prospective observational study aims to evaluate the role of ultrasound assessment of anterior neck soft tissue thickness in predicting difficult airway risk in overweight and obese adult patients undergoing elective surgery under general anesthesia. Ultrasound-based anterior neck measurements will be compared with standard clinical airway assessment parameters to determine their diagnostic accuracy for difficult laryngoscopy and intubation.

The results of this study may contribute to improved preoperative airway risk stratification and safer airway management in obese patients.

Study Overview

• Status: Not yet recruiting
• Conditions: Ultrasonography; Airway Management; Intubation, Intratracheal; Obesity and Overweight
• Intervention / Treatment: Other: None (Observational study)

Detailed Description

Difficult airway management remains a major concern in anesthetic practice and is associated with increased morbidity, particularly in obese patients. Excess anterior neck soft tissue and altered upper airway anatomy contribute to challenges in mask ventilation, laryngoscopy, and tracheal intubation. Conventional clinical airway assessment tests have limited predictive accuracy in this population, highlighting the need for additional objective assessment tools.

This prospective observational study is designed to evaluate the predictive value of ultrasound-based assessment of anterior neck soft tissue thickness for difficult airway risk in overweight and obese adult patients undergoing elective surgery under general anesthesia. The study will be conducted at a single tertiary care center after ethics committee approval, and written informed consent will be obtained from all participants.

Eligible patients aged 18-70 years with a body mass index (BMI) greater than 25 kg/m² and classified as ASA physical status I-III will be included. Emergency surgeries, pregnant patients, individuals with known difficult airway history, maxillofacial anomalies, neck masses, or a BMI greater than 60 kg/m² will be excluded.

Preoperative airway assessment will include conventional clinical parameters such as modified Mallampati score, mouth opening, interincisor distance, thyromental distance, sternomental distance, neck circumference, neck mobility, upper lip bite test, and snoring history. In addition, anterior neck ultrasound measurements will be performed preoperatively in the supine position using a high-frequency linear probe by trained anesthesiologists following a standardized protocol. Ultrasound parameters will include tongue dimensions, hyomental distance, skin-to-hyoid distance, skin-to-epiglottis distance, skin-to-vocal cords distance, skin-to-thyroid isthmus distance, skin-to-suprasternal notch distance, and the pre-epiglottic space to epiglottis-vocal cords distance ratio (PE/E-VC). Anterior neck ultrasound measurements will performed preoperatively by trained anesthesiologists using a standardized protocol.

A single prospective cohort of overweight/obese surgical patients will undergo preoperative ultrasound and clinical airway assessments, and outcomes during induction will be recorded. After induction of general anesthesia, laryngoscopic view will be assessed using the Cormack-Lehane classification. Difficult laryngoscopy will be defined as Cormack-Lehane grade III or IV. Intubation difficulty will be evaluated using the Intubation Difficulty Scale (IDS), and mask ventilation difficulty will be assessed using the Han scale. Intraoperative airway management data, including number of intubation attempts, need for adjuncts, alternative techniques, and airway-related complications, will be recorded.

Statistical analysis will focus on determining the diagnostic accuracy of ultrasound and clinical airway parameters. Receiver operating characteristic (ROC) curve analysis will be used to calculate the area under the curve (AUC), sensitivity, specificity, positive predictive value, and negative predictive value for each parameter and selected combinations. The findings aim to clarify the role of anterior neck ultrasound as a complementary tool for preoperative airway risk stratification in obese patients.

• Study Type: Observational
• Enrollment (Estimated): 52

Contacts and Locations

• Study Contact: Name: Gamze Nur Teke, medical doctor; Phone Number: +905546634389; Email: gamzenur.koca@gmail.com
• Study Contact Backup: Name: Gamze Nur Teke; Email: gamzenur.koca@gmail.com

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Overweight and obese adult patients undergoing elective surgery under general anesthesia

Description

Inclusion Criteria:

• Age 18-70 years

• ASA physical status I-III

  * BMI >25 kg/m²

• Scheduled for elective surgery under general anesthesia

Exclusion Criteria:

• Emergency surgery
• Pregnancy
• Maxillofacial anomalies or neck masses
• Rapid sequence induction
• Previous history of difficult intubation
• BMI >60 kg/m²

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Overweight and Obese Surgical Patients; Adult overweight and obese patients undergoing elective surgery under general anesthesia who will receive standard care airway management.	Other: None (Observational study); one group, there is no intervention. All measurements and observations will be performed during routine clinical care only

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cormack-Lehane grade III-IV	Occurrence of difficult airway during anesthesia induction, defined by difficult laryngoscopy	During anesthesia induction

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ultrasound-derived anterior neck soft tissue measurements	diagnostic accuracy for predicting difficult airway (ROC-AUC)	During anesthesia induction
Intubation Difficulty Scale (IDS) score	Difficult intubation: IDS score > 5	during tracheal intubation
Han Scale	Difficult mask ventilation: Han grade ≥ II	during ventilation

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Airway-related complications	Number of intubation attempts and need for airway adjuncts (stylet/bougie) and complications including desaturation and dental or soft tissue injury	during anesthesia induction

Collaborators and Investigators

• Sponsor: Gaziantep City Hospital
• Investigators: Principal Investigator: Gamze Nur Teke, medical doctor, Gaziantep City Hospital

Publications and helpful links

General Publications

• Udayakumar GS, Priya L, Narayanan V. Comparison of Ultrasound Parameters and Clinical Parameters in Airway Assessment for Prediction of Difficult Laryngoscopy and Intubation: An Observational Study. Cureus. 2023 Jul 5;15(7):e41392. doi: 10.7759/cureus.41392. eCollection 2023 Jul.
• Kaul R, Singh D, Prakash J, Priye S, Kumar S, Bharati. Ultrasound Guided Measurement of Anterior Neck Tissue for the Prediction of Difficult Airway: A Prospective Observational Study. Rom J Anaesth Intensive Care. 2022 Dec 29;28(2):105-110. doi: 10.2478/rjaic-2021-0018. eCollection 2021 Dec.
• Akin S, Yildirim M, Artas H, Bolat E. Predicting difficult airway in morbidly obese patients using ultrasound. Turk J Med Sci. 2023 Nov 21;54(1):262-274. doi: 10.55730/1300-0144.5787. eCollection 2024.

Study record dates

Study Major Dates

• Study Start (Estimated): January 20, 2026
• Primary Completion (Estimated): May 20, 2026
• Study Completion (Estimated): June 20, 2026

Study Registration Dates

• First Submitted: January 8, 2026
• First Submitted That Met QC Criteria: January 8, 2026
• First Posted (Estimated): January 16, 2026

Study Record Updates

• Last Update Posted (Estimated): January 16, 2026
• Last Update Submitted That Met QC Criteria: January 8, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Obesity; ultrasonography; difficult airway; anterior neck ultrasound
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Overweight; Obesity; Investigative Techniques; Methods; Observation
• Other Study ID Numbers: GaziantepCH

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared due to institutional data protection policies and the absence of participant consent for data sharing beyond the scope of the study.

Drug and device information, study documents

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