Can the "Face Index"; an Anthropometric Measurement, Predict Difficult Laryngoscopy and Intubation?

NCT07366177 | Not Yet Recruiting

• 1 other identifier: NTasFACE
• Study Type: observational
• Target: 1,000
• Locations: 0 countries
• Sites: N/A

Brief Summary

Patient safety is the cornerstone of anesthetic practice, and maintaining adequate respiration represents its most critical initial step. In situations where spontaneous breathing cannot be sustained-such as during general anesthesia-the airway must be mechanically secured. While simple face masks may be sufficient in some cases, endotracheal intubation remains the most reliable method for airway control in conditions associated with respiratory depression. Airway management may be challenging due to various patient-related anatomical factors, including facial and mandibular structure, obesity, limited mouth opening, facial hair, sunken cheeks, wide facial morphology, and a short or muscular neck. These challenges are collectively described as difficult ventilation and difficult intubation (cannot ventilate-cannot intubate), which may occur unexpectedly or be anticipated. A difficult airway is defined as difficulty encountered by a trained anesthesiologist in face mask ventilation, tracheal intubation, or both. Several predictors of difficult airway are widely accepted, such as thyromental and sternomental distances, neck circumference, Mallampati classification, upper lip bite test, mouth opening, and interincisor distance. Thorough preoperative airway evaluation is mandatory, as difficult mask ventilation and failed intubation remain major contributors to anesthesia-related morbidity and mortality. Although numerous studies have examined these predictors, research focusing on facial morphology and anthropometric indices-particularly the face index-is extremely limited. Facial morphology varies considerably among individuals and can be evaluated anthropometrically using simple, noninvasive tools such as a digital caliper. Anthropometric analysis is commonly applied in forensic medicine and reconstructive surgery but has rarely been incorporated into airway assessment. This study aims to introduce face index analysis as a novel predictor of difficult airway alongside conventional methods. By evaluating measurements such as trichion-gnathion distance, total facial index, upper facial index, and nasal index, the study investigates whether airway difficulty can be predicted using a single index value. All measurements are standard, noninvasive, and routinely performed during preoperative assessment.

Conditions

Anesthesia Intubation Complication; Intubation; Difficult or Failed; Laryngoscopy; Anesthesia Morbidity

Keywords

Difficult airway, face index, anesthesia

Outcome Measures

Primary Outcomes (2)

• 1. The facial index: Unit of Measure: Ratio (dimensionless) 2. Upper Face Height: Unit of Measure: mm 3. Total Face Height: Unit of Measure: mm 4. Mallampati: Categorical (Class I-IV) 5. Difficult Airway: Categorical (yes / no)

  1. The facial index in will be calculated as the ratio of total face height (nasion-gnathion) to bizygomatic width measured preoperatively. 2. Upper Face Height: Linear distance between subnasale and stomion measured preoperatively. 3. Total Face Height: Linear distance between nasion and gnathion measured preoperatively. 4. Mallampati Categorical (Class I-IV): Airway classification assessed preoperatively. 5. Difficult Airway: Categorical (yes / no): Defined as the presence of difficult mask ventilation and/or difficult intubation.

  Preoperative period (before induction of anesthesia)

• Face index and face mask ventilation

  Facial Anthropometric Measurements: Facial anthropometric measurements, including trichion-gnathion distance, upper face height (subnasale-stomion), total face height (nasion-gnathion), bizygomatic width, and alar width, measured preoperatively and recorded for each participant.

  Preoperative period (before induction of anesthesia)

Secondary Outcomes (1)

• Facial Index and Preoperative Airway Assessment Parameters

  Preoperative period (before induction of anesthesia)

Interventions

Face index OTHER

Face index is an anthropometric measurement

Eligibility Criteria

• Age: 18 Years - 95 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

All patients who have general anesthesia

You may qualify if:

• Adult patients over the age of 18
• Patients who received general anesthesia

You may not qualify if:

• A prior history of difficult airway
• All patients who have undergone facial deformities
• All patients who have tracheostomy
• \. Children patients 6. Pregnant patients

Sponsors & Collaborators

• Ordu University: lead

Related Publications (6)

• 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.

  PMID: 34762729 RESULT

• Coskun A, Duzgun SA, Bozer M, Akinci OF, Uzunkoy A. Modified technique for correction of gynaecomastia. Eur J Surg. 2001 Nov;167(11):822-4. doi: 10.1080/11024150152717643.

  PMID: 11848235 RESULT

• Jackson JS, Rondeau B. Mallampati Score. 2025 Jul 7. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from http://www.ncbi.nlm.nih.gov/books/NBK585119/

  PMID: 36256766 RESULT

• Chow HH, Tolle KM, Roe DJ, Elsberry V, Chen H. Application of neural networks to population pharmacokinetic data analysis. J Pharm Sci. 1997 Jul;86(7):840-5. doi: 10.1021/js9604016.

  PMID: 9232526 RESULT

• Garber DA, Beverley SM, Coen DM. Demonstration of circularization of herpes simplex virus DNA following infection using pulsed field gel electrophoresis. Virology. 1993 Nov;197(1):459-62. doi: 10.1006/viro.1993.1612.

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• Vidon N, Palma R, Bernier JJ. [Water-electrolyte movements along the human intestine in diarrhea induced by mannitol]. Gastroenterol Clin Biol. 1983 Jan;7(1):23-9. No abstract available. French.

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Study Officials

• Nilay Taş, Prof. Dr.

  Ordu University School of Medicine, Türkiye

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Yasir İlyas, Ass. Prof.

CONTACT

+904522252344; yasirilyas@odu.edu.tr

Halil Yılmaz, Ass. Prof.

CONTACT

+904522252344; halilyilmaz855@gmail.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Prof. Dr.

Study Record Dates

• First Submitted: January 18, 2026
• First Posted: January 26, 2026
• Study Start (Estimated): November 1, 2026
• Primary Completion (Estimated): November 1, 2027
• Study Completion (Estimated): November 1, 2027
• Last Updated: August 24, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will not share