Combined Ultrasound and Upper Lip Bite Test Assessment of Difficult Laryngoscopy in Obese Patients

NCT07642206 | Not Yet Recruiting DMC

• 1 other identifier: Airway Ultrasound
• Study Type: interventional
• Target: 134
• Locations: 1 country
• Sites: 1

Brief Summary

The aim of this observational study is to evaluate the accuracy of the HMDR combined with the ULBT as a predictor of difficult laryngoscopy in obese patients undergoing elective surgery under general anesthesia, regarding:

• Correlation of HMDR-ULBT values with Cormack-Lehane grades during laryngoscopy.
• Comparison of HMDR-ULBT with standard HMDR in predicting difficult laryngoscopy.

Conditions

Airway Assessment

Keywords

airway ultrasound; upper lip bite test

Outcome Measures

Primary Outcomes (1)

• Prediction of difficult laryngoscopic view, defined as Cormack-Lehane Grade 3 or 4 on the first laryngoscopy attempt without external laryngeal manipulation.

  Difficult laryngoscopic view is defined as Cormack-Lehane Grade III or IV during the first laryngoscopy attempt without external laryngeal manipulation Cormack-Lehane classification for laryngoscopic view : grade 1: most of the vocal cords is seen; grade 2: only the posterior part of the vocal cords or the arytenoid cartilages are seen; grade 3: only epiglottis is seen; grade 4: epiglottis is not seen.

  Day of surgery from preoperative assessment to first laryngoscopy attempt after induction of general anethesia and after three minutes of mask ventilation.

Secondary Outcomes (2)

• Determination of an optimal cutoff value for HMDR-ULBT to predict difficult laryngoscopy.

  From preoperative airway assessment until completion of the first laryngoscopy attempt during induction of anesthesia on the day of surgery

• Comparison of HMDR-ULBT with standard HMDR in predicting difficult laryngoscopy.

  From preoperative airway assessment until completion of the first laryngoscopy attempt during induction of anesthesia.

Study Arms (1)

HMD measured by US in neutral head position , maximum head extension and during upper lip bite test

OTHER

Hyomental distance will be measured using ultrasound in three positions: neutral head position, maximum head extension, and during the upper lip bite test (ULBT).

Diagnostic Test: Hyomental distance measured using ultrasound in neutral head position, maximum head extension and during upper lip bite test

Interventions

Hyomental distance measured using ultrasound in neutral head position, maximum head extension and during upper lip bite test DIAGNOSTIC_TEST

Hyomental distance will be measured using ultrasound in three positions: neutral head position, maximum head extension, and during the upper lip bite test (ULBT).

HMD measured by US in neutral head position , maximum head extension and during upper lip bite test

Eligibility Criteria

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

You may qualify if:

• Adult obese patients aged 18 to 65 years.
• Both sexes.
• American Society of Anesthesiologists (ASA) physical status II- III.
• Body Mass Index (BMI) ≥ 30 kg/m² (classified as obese).
• Scheduled for elective surgical procedures requiring general anesthesia with endotracheal intubation.
• Ability to understand and provide informed written consent.
• Cooperative and able to perform the ULBT on command.
• Normal dentition (presence of upper and lower incisors to perform ULBT accurately).

You may not qualify if:

• History of maxillofacial trauma, surgery, or congenital facial anomalies affecting mandibular movement or neck anatomy.
• Known or suspected difficult airway requiring awake intubation.
• Patients with limited neck mobility (e.g., cervical spine disease or immobilization).
• Temporomandibular joint disorders or restricted mandibular mobility.
• Pregnancy.

Sponsors & Collaborators

• Cairo University: lead

Study Sites (1)

Kasr Al-Ainy Hospital, Cairo University

Cairo, Cairo Governorate, Egypt

Location

Related Publications (4)

• Bhanushali A, Date A. Evaluation of upper lip bite test and thyromental height test for prediction of difficult laryngoscopy: A prospective observational study. Airway. 2021;4(3):621-42.

  BACKGROUND

• Hrithma D, K R, Mahadevaiah DT, K N V. A Cross-Sectional Study on Hyomental Distance Ratio (HMDR) as a New Predictor of Difficult Laryngoscopy in ICU Patients. Cureus. 2022 May 28;14(5):e25435. doi: 10.7759/cureus.25435. eCollection 2022 May.

  PMID: 35774688 BACKGROUND

• Liaskou C, Vouzounerakis E, Trikoupi A, Staikou C. [Evaluation of bedside tests and proposal of a model for predicting difficult laryngoscopy: an observational prospective study]. Braz J Anesthesiol. 2020 Mar-Apr;70(2):125-133. doi: 10.1016/j.bjan.2020.02.007. Epub 2020 May 13.

  PMID: 32482358 BACKGROUND

• Liu Y, He Y, Wang X, Li J, Zhang Z, Zhuang X, et al. Advances in airway management in recent 10 years from 2013 to 2023. Anesthesiol Perioper Sci. 2023;1(4):27-30.

  BACKGROUND

Central Study Contacts

Makarious Morris Aboelkheir, MSc

CONTACT

+201225246321; makariousmorris0@gmail.com

Yasmin Khaled Ahmed, MD

CONTACT

+201095015566; dr_ykh@hotmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: OTHER
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Lecturer of Anesthesiology

Model Details: Hyomental distance will be measured using ultrasound in three different positions, neutral head position , maximum head extension and during performing upper lip bite test .

Study Record Dates

• First Submitted: June 7, 2026
• First Posted: June 11, 2026
• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): March 1, 2027
• Last Updated: June 12, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

EG (1)