New Method for Evaluation of Difficult Intubation in Adults

NCT07461792 | Active Not Recruiting

• 1 other identifier: Soh-Med-26-2-15MS
• Study Type: observational
• Target: 350
• Locations: 1 country
• Sites: 1

Brief Summary

There are multiple scores used for airway assesment ,the commonest one is LEMON score. LEMON is an airway assessment score that measures factors associated with difficult intubation such as obesity, head and neck movement, jaw movement , receding mandible, long upper incisors, Mallampatti scores, maxillary incisor characteristics, decreased mouth opening ,shorten thyromental distance and short neck. The Height-to-Thyromental Distance ratio (H/TMD) has emerged as a simple, objective, and reproducible anatomical predictor of difficult laryngoscopy, as it normalizes mandibular space to patient height. However, airway difficulty is not purely anatomical; functional factors such as airway obstruction and cervical spine mobility significantly affect intubation success. Therefore, combining H/TMD with two highly predictive functional elements from the LEMON score - Obstruction (O) and Neck Mobility (N) - may provide a more accurate, simplified, and clinically applicable model for predicting difficult airway. This combination is referred to as the HON Model (Height/TMD + Obstruction + Neck mobility).

Conditions

Difficult Airway Intubation

Outcome Measures

Primary Outcomes (1)

• The primary outcome evaluate using Ratio of Patient's Height to Thyromental Distance Combined with Obstruction and Neck Mobility (HON Model) as a new practical scoring system in predicting Difficult Laryngoscopy .

  30 minutes

Study Arms (1)

- Adult patients from 15- 60 yrs old - Patients who require endotracheal intubation for su

Other: evaluation of difficult intubation

Interventions

evaluation of difficult intubation OTHER

The Height-to-Thyromental Distance ratio (H/TMD) has emerged as a simple, objective, and reproducible anatomical predictor of difficult laryngoscopy, as it normalizes mandibular space to patient height. However, airway difficulty is not purely anatomical; functional factors such as airway obstruction and cervical spine mobility significantly affect intubation success. Therefore, combining H/TMD with two highly predictive functional elements from the LEMON score - Obstruction (O) and Neck Mobility (N) - may provide a more accurate, simplified, and clinically applicable model for predicting difficult airway. This combination is referred to as the HON Model (Height/TMD + Obstruction + Neck mobility).

- Adult patients from 15- 60 yrs old - Patients who require endotracheal intubation for su

Eligibility Criteria

• Age: 15 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)
• Sampling Method: Probability Sample

Study Population

The sample size calculation was performed using G. power 3.1.9.2 (Universitat Kiel, Germany) and total sample size will be 350. It was calculated according to a previous study (Pal et al., 2025, Rista et al., 2025) based the sensitivity of Height/Thyromental Distance Ratio and L.E.M.O.N score as to best of our knowledge our study will be the first to assess Height/Thyromental Distance Ratio Combined with Obstruction and Neck Mobility (HON Model) to predict difficult intubation (Power : 0.8, α error: 0.05).

You may qualify if:

• Adult patients from 15- 60 yrs old
• Patients who require endotracheal intubation for surgery under general anesthesia.
• Patients with ASA I - II
• Patients who provide informed consent

You may not qualify if:

• Patients with history of previous difficult intubation.
• Patients with inability to sit/stand, heamodinamiclly unstable and need for rapid sequence induction .

Sponsors & Collaborators

• Sohag University: lead

Study Sites (1)

Faculty of Medicine Sohag University

Sohag, Nasser City, Egypt

Location

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 1 Day
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Anesthesia and ICU Resident at Sohag faculty of medicine

Study Record Dates

• First Submitted: March 5, 2026
• First Posted: March 10, 2026
• Study Start: January 5, 2026
• Primary Completion: June 15, 2026
• Study Completion: July 15, 2026
• Last Updated: April 17, 2026

Record last verified: 2026-04

Locations

EG (1)