The Impact of Ultrasound Measurements in Predicting Difficult Airway on Videolaryngoscopy Success

Impact of Airway Ultrasound Measurements on the Success of Videolaryngoscopy in Predicting Difficult Airway

In this preoperative observational study, the effect of preoperative ultrasonographic measurements on the success of videolaryngoscopy in predicting difficult airways was investigated; furthermore, the aim was to determine new cut-off values that can predict difficult intubation in videolaryngoscope use. In our study, it was tested that the use of videolaryngoscope significantly increased the success of intubation in patients who were assessed as having difficult airways with upper airway ultrasound measurements.

Study Overview

• Status: Active, not recruiting
• Conditions: Ultrasonography; Difficult Airway

Detailed Description

Upper airway ultrasonography has emerged as a promising tool for difficult airway assessment by enabling non-invasive, bedside, repeatable, and objective evaluation of airway anatomy. However, a substantial proportion of the existing literature has correlated ultrasonographic measurements with direct laryngoscopy findings. Whether these measurements retain their predictive value in the setting of videolaryngoscopy, and which ultrasonographic parameters best reflect technical intubation difficulty during videolaryngoscopic intubation, remain unclear. Furthermore, several studies have proposed specific cut-off values for upper airway ultrasonographic measurements to predict difficult laryngoscopy when direct laryngoscopy is used. However, these cut-off values may not be directly applicable to videolaryngoscopy because the improved glottic visualization provided by videolaryngoscopes fundamentally alters the relationship between airway anatomy and intubation difficulty.

Therefore, after obtaining a detailed medical history, including both general medical and difficult airway-related history, all patients underwent a comprehensive airway assessment. Conventional predictors of difficult airway were evaluated, including Mallampati classification, inter-incisor distance, thyromental distance, atlanto-occipital joint extension, neck circumference, and the upper lip bite test.

On the day of surgery, ultrasonographic measurements including the distance from the skin to the epiglottis (ESD), hyomental distance (HMD), tongue thickness (TT), and tongue cross-sectional area (CSA) will be obtained. Following these assessments, patients will be transferred to the operating room, where standard general anesthesia induction will be performed. Orotracheal intubation will subsequently be carried out using a videolaryngoscope. After intubation, the difficulty of mask ventilation, laryngoscopy, and orotracheal intubation will be evaluated by the anesthesiologist using established clinical assessment tools and scoring systems.

• Study Type: Observational
• Enrollment (Actual): 350

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Bakirköy
    • Istanbul, Bakirköy, Turkey (Türkiye), 34147
      • SBÜ Bakırköy Dr. Sadi Konuk Eğitim ve Araştırma Hastanesi

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Patients undergoing elective surgery under general anesthesia requiring endotracheal intubation

Description

Inclusion Criteria:

• Patients aged 18 years and older
• Patients undergoing elective surgery under general anesthesia requiring endotracheal intubation (ASA I-III)

Exclusion Criteria:

• Patients undergoing surgery under sedation or regional anesthesia
• Patients not planned for endotracheal intubation
• Patients with a history of difficult airway
• Patients with an acute respiratory tract infection
• Patients with congenital or acquired upper airway anomalies
• Patients with facial or maxillofacial tumors or fractures
• Patients with cervical spine fracture
• Patients with a history of cervical or craniofacial radiotherapy
• Patients with a tracheostomy
• Pregnant patients
• Patients who do not meet the required fasting period or who refuse to -participate in the study

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
None (Orotracheal intubation will be performed using a videolaryngoscope in all patients); Patients aged 18 years and older, classified as American Society of Anesthesiologists (ASA) physical status I-III, who will undergo surgery under general anesthesia requiring orotracheal intubation, will be included in this prospective observational study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difficult videolaryngoscopic intubation	Difficult videolaryngoscopic intubation will be assessed using the VIDIAC score, a scoring system specifically developed to quantify intubation difficulty during videolaryngoscopy.	During videolaryngoscopy (periprocedural)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difficult mask ventilation	Difficult mask ventilation will be assessed after anesthesia induction and during ventilation.	During ventilation (periprocedural)

Collaborators and Investigators

• Sponsor: Bakirkoy Dr. Sadi Konuk Research and Training Hospital

Publications and helpful links

General Publications

• Kheterpal S, Han R, Tremper KK, Shanks A, Tait AR, O'Reilly M, Ludwig TA. Incidence and predictors of difficult and impossible mask ventilation. Anesthesiology. 2006 Nov;105(5):885-91. doi: 10.1097/00000542-200611000-00007.
• Kheterpal S, Martin L, Shanks AM, Tremper KK. Prediction and outcomes of impossible mask ventilation: a review of 50,000 anesthetics. Anesthesiology. 2009 Apr;110(4):891-7. doi: 10.1097/ALN.0b013e31819b5b87.
• Apfelbaum JL, Hagberg CA, Connis RT, Abdelmalak BB, Agarkar M, Dutton RP, Fiadjoe JE, Greif R, Klock PA, Mercier D, Myatra SN, O'Sullivan EP, Rosenblatt WH, Sorbello M, Tung A. 2022 American Society of Anesthesiologists Practice Guidelines for Management of the Difficult Airway. Anesthesiology. 2022 Jan 1;136(1):31-81. doi: 10.1097/ALN.0000000000004002.
• Wu J, Dong J, Ding Y, Zheng J. Role of anterior neck soft tissue quantifications by ultrasound in predicting difficult laryngoscopy. Med Sci Monit. 2014 Nov 18;20:2343-50. doi: 10.12659/MSM.891037.
• Gomes SH, Simoes AM, Nunes AM, Pereira MV, Teoh WH, Costa PS, Kristensen MS, Teixeira PM, Pego JM. Useful Ultrasonographic Parameters to Predict Difficult Laryngoscopy and Difficult Tracheal Intubation-A Systematic Review and Meta-Analysis. Front Med (Lausanne). 2021 May 28;8:671658. doi: 10.3389/fmed.2021.671658. eCollection 2021.

Study record dates

Study Major Dates

• Study Start (Actual): December 21, 2025
• Primary Completion (Estimated): June 10, 2026
• Study Completion (Estimated): July 20, 2026

Study Registration Dates

• First Submitted: December 15, 2025
• First Submitted That Met QC Criteria: June 1, 2026
• First Posted (Actual): June 5, 2026

Study Record Updates

• Last Update Posted (Actual): June 5, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Ultrasonography; Difficult airway; Difficult mask ventilation; Difficult laryngoscopy
• Other Study ID Numbers: 2025/46

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared because the study contains personal health information and no regulatory or ethics approval has been obtained for external data sharing.

Drug and device information, study documents

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