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Tracheal Intubation, Elective SurgeryNCT07609147

Ultrasound Measurement of Skin-to-Epiglottis Distance for Prediction of Difficult Airway in Adult Patients

An observational study of Tracheal Intubation, Elective Surgery and Tracheal Diamater Measurement, run by Hacettepe University at 1 site in Turkey (Türkiye).

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Sites and contacts
Official record
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Trial summary

This prospective observational study aims to evaluate the predictive value of ultrasound-measured skin to epiglottis distance for difficult airway in adult patients undergoing elective or emergency procedures requiring airway management. Read more about this study

Who is it for?
Ages 18 years and older
How many people
300 participants
Where
1 siteTurkey (Türkiye)
Study dates
1 Jul 2026to 4 Dec 2026
Phase
Observational
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Study population: The study population consists of adult patients scheduled for elective surgery requiring tracheal intubation under general anesthesia. Patients will be recruited from the preoperative anesthesia clinic at [Hacettepe University Faculty of Medicine]

Who may be able to join

  • ≥18 yaş elective surgery

Who cannot join

  • emergency surgery
  • head and neck surgery
  • pregnant patients

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Almıla G Pamuk, Doç. Dr. contact

9005335296325 ext. 03123051207

gulsunp@yahoo.com

muhammed r hız, research assistant contact

9005417800327 ext. 9003123051207

drrasithiz@gmail.com

Turkey (Türkiye)1 site

  • Hacettepe Univercity

    Ankara, Altındağ, 06320

Other trials in Turkey (Türkiye)

About this study

Official title: Ultrasound Measurement of Skin to Epiglottis Distance for Prediction of Difficult Airway in Adult Patients

This prospective observational study aims to evaluate the predictive value of ultrasound-measured skin to epiglottis distance for difficult airway in adult patients undergoing elective or emergency procedures requiring airway management. The correlation between ultrasound measurements and standard airway assessment parameters will be analyzed.

Read the detailed description

Airway management is a critical component of anesthesia and intensive care practice. Predicting difficult airway remains challenging with conventional bedside tests. Ultrasound has emerged as a non-invasive, bedside tool for airway assessment. This study aims to investigate the relationship between skin-to-epiglottis distance measured by ultrasound and difficult laryngoscopy/intubation. Secondary comparisons will include traditional airway assessment methods such as Mallampati score, thyromental distance, and neck circumference

Keywords
ultrasound, airway, epiglottis, Skin-to-Epiglottis Distance, Difficult Airway Prediction

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Skin to epiglottis distance

    Distance measured via ultrasound in the anterior neck region

    Measured: Preintubation (within 30 minutes before procedure)

Secondary outcomes (4)

  1. Incidence of difficult laryngoscopy (Cormack-Lehane grade ≥ 3)

    The proportion of patients with difficult laryngoscopy defined as Cormack-Lehane grade 3 or 4 during direct laryngoscopy.

    Measured: During intubation procedure (intraoperative period)

  2. Intubation Difficulty Score (IDS)

    Assessment of intubation difficulty using the Intubation Difficulty Score based on number of attempts, operators, alternative techniques, glottic exposure, lifting force, external laryngeal pressure, and vocal cord position.

    Measured: During intubation procedure

  3. Correlation between ultrasound measurements and Mallampati score

    Correlation between tracheal diameter and skin to epiglottis distance measured by ultrasound and preoperative Mallampati classification.

    Measured: Preoperative assessment

  4. Skin-to-Epiglottis Distance Measured by Ultrasound

    Skin-to-epiglottis distance will be measured using ultrasound immediately before anesthesia induction. The distance is recorded in millimeters (mm) as a continuous variable. Larger values indicate a greater skin-to-epiglottis distance and may be associated with an increased likelihood of difficult laryngoscopy. This is not a scored scale; therefore, no predefined minimum or maximum score exists.Cormack-Lehane Grading System. Scores range from Grade I to Grade IV. Grade I indicates full visualization of the glottis (easier laryngoscopy), whereas Grade IV indicates that neither the glottis nor the epiglottis is visible (most difficult laryngoscopy). Higher grades indicate a worse airway view.

    Measured: Immediately before induction of anesthesia

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted27 May 2026
  2. Study start1 Jul 2026 (estimated)
  3. Primary completion1 Nov 2026 (estimated)
  4. Study completion4 Dec 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Case-control
Time perspective
Prospective
Enrolment
300 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07609147
Sponsor's protocol ID
SBA 26/158
Status last verified
Jul 2026
First submitted
20 May 2026
Last updated
17 Jul 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Yes: Diffuculty airway

Publications

  • Gani, E. (2020). Obez hastalarda zor entübasyonun öngörülmesinde ultrasonla ölçülen cilt-epiglot mesafesinin önemi (Tıpta Uzmanlık Tezi). Düzce Üniversitesi, Tıp Fakültesi, Anesteziyoloji ve Reanimasyon Anabilim Dalı, Düzce.

  • Uzumcugil F, Celebioglu EC, Ozkaragoz DB, Yilbas AA, Akca B, Lotfinagsh N, Celebioglu B. Body Surface Area Is Not a Reliable Predictor of Tracheal Tube Size in Children. Clin Exp Otorhinolaryngol. 2018 Dec;11(4):301-308. doi: 10.21053/ceo.2018.00178. Epub 2018 Aug 25.

    PubMed 30139232

  • Ahmad I, El-Boghdadly K, Iliff H, Dua G, Higgs A, Huntington M, Mir F, Nouraei SAR, O'Sullivan EP, Patel A, Rivett K, McNarry AF. Difficult Airway Society 2025 guidelines for management of unanticipated difficult tracheal intubation in adults. Br J Anaesth. 2026 Jan;136(1):283-307. doi: 10.1016/j.bja.2025.10.006. Epub 2025 Nov 7.

    PubMed 41203471

  • Altinsoy KE, Bayhan BU. Ultrasound-Measured Skin-to-Epiglottis Distance as a Predictor of Difficult Intubation in Obese Patients: A Prospective Observational Study. J Clin Med. 2025 Mar 19;14(6):2092. doi: 10.3390/jcm14062092.

    PubMed 40142901

  • Sayir TN, Tuncer B, Erkilic E. Evaluation of upper airway ultrasonographic measurements in predicting difficult intubation: A cross-section of the Turkish population. Open Med (Wars). 2024 Aug 21;19(1):20241013. doi: 10.1515/med-2024-1013. eCollection 2024.

    PubMed 39176250

  • Cinar Kose EO, Tekin M, Cesur S, Cam I, Baykara ZN. Evaluation of neck ultrasound measurements as a difficult airway predictor: A prospective observational study. Medicine (Baltimore). 2024 Jul 19;103(29):e38591. doi: 10.1097/MD.0000000000038591.

    PubMed 39029084

  • Daggupati H, Maurya I, Singh RD, Ravishankar M. Development of a scoring system for predicting difficult intubation using ultrasonography. Indian J Anaesth. 2020 Mar;64(3):187-192. doi: 10.4103/ija.IJA_702_19. Epub 2020 Mar 11.

    PubMed 32346164

  • Sotoodehnia M, Rafiemanesh H, Mirfazaelian H, Safaie A, Baratloo A. Ultrasonography indicators for predicting difficult intubation: a systematic review and meta-analysis. BMC Emerg Med. 2021 Jul 3;21(1):76. doi: 10.1186/s12873-021-00472-w.

    PubMed 34217221

  • Cook TM, Woodall N, Frerk C; Fourth National Audit Project. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. Br J Anaesth. 2011 May;106(5):617-31. doi: 10.1093/bja/aer058. Epub 2011 Mar 29.

    PubMed 21447488

  • Zhang W, Du L, Huang Y, Liu D, Li T, Zheng J. Artificial intelligence for difficult airway assessment: a protocol for a systematic review with meta-analysis. BMJ Open. 2025 Jun 10;15(6):e096744. doi: 10.1136/bmjopen-2024-096744.

    PubMed 40499971

  • Falcetta S, Cavallo S, Gabbanelli V, Pelaia P, Sorbello M, Zdravkovic I, Donati A. Evaluation of two neck ultrasound measurements as predictors of difficult direct laryngoscopy: A prospective observational study. Eur J Anaesthesiol. 2018 Aug;35(8):605-612. doi: 10.1097/EJA.0000000000000832.

    PubMed 29889671

Questions about this trial

What is this clinical trial studying?

An observational study of Tracheal Intubation, Elective Surgery and Tracheal Diamater Measurement, run by Hacettepe University at 1 site in Turkey (Türkiye).

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 1 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: opening soon, as of the sponsor's last update on 17 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Almıla G Pamuk, Doç. Dr. (9005335296325 ext. 03123051207, gulsunp@yahoo.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Skin to epiglottis distance (time frame: Preintubation (within 30 minutes before procedure)). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07609147, which also lists 11 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Jul 2026.

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