Combined Ultrasonographic Skin-to-Epiglottis Distance With Modified Mallampati Versus Modified Mallampati Score Alone in Predicting Difficult Laryngoscopy During Tracheal Intubation Under General Anesthesia

NCT07315256 | Not Yet Recruiting

• 1 other identifier: Ultrasound in Intubation
• Study Type: interventional
• Target: 160
• Locations: 0 countries
• Sites: N/A

Brief Summary

This study will evaluate how well an ultrasound measurement of the distance from the skin to the epiglottis, when combined with the modified Mallampati score, can predict difficult laryngoscopy in adult patients undergoing elective surgery under general anesthesia. Adult patients scheduled for surgery requiring tracheal intubation will be randomly assigned to two assessment strategies before anesthesia: one group will have the usual bedside airway assessment with modified Mallampati alone, and the other group will have modified Mallampati plus a quick, painless ultrasound scan of the front of the neck to measure the skin-to-epiglottis distance. During intubation, the anesthesiologist, who is blinded to the preoperative assessments, will grade the laryngoscopic view using the Cormack-Lehane classification, and the investigators will compare how accurately each assessment approach predicts difficult laryngoscopy (grade 3-4). The study does not change how anesthesia or airway management is performed; ultrasound and clinical assessments are added solely for measurement and data collection, with minimal risk to participants and potential future benefits in improving airway risk stratification and patient safety.

Conditions

Ultrasonographic; Mallampati Score; Mallampati Score, Difficult Intubation, Videolaryngoscope; Tracheal Intubation

Keywords

Difficult Laryngoscopy; Tracheal Intubation; Modified Mallampati

Outcome Measures

Primary Outcomes (1)

• Diagnostic accuracy of Ultrasonographic Skin-to-Epiglottis Distance plus Mallampati vs Mallampati alone for difficult laryngoscopy

  Area under the receiver operating characteristic (ROC) curve (AUC) of the combined ultrasound skin-to-epiglottis distance plus modified Mallampati score compared with the AUC of the modified Mallampati score alone for predicting difficult laryngoscopy, defined as Cormack-Lehane grade 3-4 on first direct laryngoscopy attempt.

  From induction of anesthesia to completion of first direct laryngoscopy (intraoperative, approximately 10 minutes).

Secondary Outcomes (1)

• Correlation between skin-to-epiglottis distance and Cormack-Lehane grade

  From preoperative ultrasound assessment to completion of first direct laryngoscopy (same operative session, approximately 30 minutes).

Study Arms (2)

Modified Mallampati Only

ACTIVE COMPARATOR

Adult elective surgical patients will undergo standard preoperative airway assessment using the modified Mallampati score only. No airway ultrasound will be performed. An experienced anesthesiologist, blinded to all preoperative assessments, will perform direct laryngoscopy for tracheal intubation and record the Cormack-Lehane grade on first attempt.

Diagnostic Test: Clinical Airway Assessment With Modified Mallampati Score

Mallampati Plus Ultrasound Skin-to-Epiglottis Distance

EXPERIMENTAL

Adult elective surgical patients will undergo standard preoperative airway assessment with the modified Mallampati score plus point-of-care airway ultrasound to measure the midline skin-to-epiglottis distance using a high-frequency linear probe at the thyrohyoid membrane. The measurement is non-invasive and does not change clinical management. An experienced anesthesiologist, blinded to both Mallampati and ultrasound results, will perform direct laryngoscopy for tracheal intubation and record the Cormack-Lehane grade on first attempt.

Diagnostic Test: Ultrasound-Guided Skin-to-Epiglottis Distance Measurement

Interventions

Ultrasound-Guided Skin-to-Epiglottis Distance Measurement DIAGNOSTIC_TEST

Point-of-care airway ultrasound of the anterior neck using a high-frequency linear probe (10-13 MHz) placed transversely at the thyrohyoid membrane to measure the vertical skin-to-epiglottis distance in millimeters. The scan is performed preoperatively in supine neutral position, is non-invasive and painless, and does not alter anesthetic or airway management, which follow standard clinical practice. This measurement is combined with the modified Mallampati score in the experimental arm to predict difficult laryngoscopy (Cormack-Lehane grade 3-4).

Mallampati Plus Ultrasound Skin-to-Epiglottis Distance

Clinical Airway Assessment With Modified Mallampati Score DIAGNOSTIC_TEST

Standard preoperative bedside airway assessment using the modified Mallampati score without airway ultrasound; performed in the sitting position with mouth opening and maximal tongue protrusion, used routinely to anticipate difficulty of laryngoscopy.

Modified Mallampati Only

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults aged 18-65 years.
• ASA physical status I-II.
• Scheduled for elective surgery under general anesthesia requiring tracheal intubation with direct laryngoscopy.
• Able to provide written informed consent.

You may not qualify if:

• Emergency surgery.
• Known or suspected difficult airway requiring planned alternative intubation technique (e.g., awake fiberoptic).
• History of significant upper airway pathology, neck mass, prior neck surgery, or radiation affecting airway anatomy.
• Limited mouth opening, cervical spine instability, or contraindication to standard sniffing position.
• Pregnancy.
• Refusal or inability to provide informed consent.

Sponsors & Collaborators

• Assiut University: lead

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: DIAGNOSTIC
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Resident at Anesthesia and ICU Department, Assiut University

Study Record Dates

• First Submitted: December 18, 2025
• First Posted: January 2, 2026
• Study Start: January 1, 2026
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): February 1, 2027
• Last Updated: January 2, 2026

Record last verified: 2025-12