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Airway ManagementNCT02957084

Anatomic Features of the Neck and Preoperative Tests as Predictive Markers of Difficult Laryngoscopy

An observational study of Airway Management and Predictive Value of Tests, run by National and Kapodistrian University of Athens.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

In this prospective, open cohort study the diagnostic value of tests based on neck anatomy in predicting difficult laryngoscopy was assessed. The anatomic features of the neck measured were head extension, mouth opening, upper lip bite, Mallampati class, thyromental distance, sternomental distance, ratio of height to… Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Airway Management, Predictive Value of Tests
How many people
1,142 participants
Where
No sites listed yet
Study dates
Mar 2013to Dec 2014
Phase
Observational
Are there results?
None posted in the registry

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: Adult patients with BMI less than 35 kg/m2, wihthout any known neck or airway pathology, scheduled for surgical procedures under general anaesthesia with tracheal intubation were assessed for eligibility to be included in the study.

Who may be able to join

  • Adult patients
  • BMI less than 35 kg/m2
  • No known neck or airway pathology
  • Scheduled for surgical procedures under general anaesthesia with tracheal intubation

Who cannot join

  • Age less than 18 years
  • BMI higher than 35 kg/m2
  • Obvious airway malformations
  • Need for rapid sequence induction/intubation under cricoid pressure
  • Awake intubation
  • Cervical spine pathology requiring specific manipulation
  • Obstetric cases

About this study

Official title: Anatomic Features of the Neck and Preoperative Tests as Predictive Markers of Difficult Direct Laryngoscopy

In this prospective, open cohort study the diagnostic value of tests based on neck anatomy in predicting difficult laryngoscopy was assessed.

The anatomic features of the neck measured were head extension, mouth opening, upper lip bite, Mallampati class, thyromental distance, sternomental distance, ratio of height to thyromental, neck circumference, thyrosternal distance, hyomental distance at full head extension (FHE) and at neutral position (NP), ratio of neck circumference to thyromental distance and ratio of hyomental distance FHE to hyomental distance NP.

Read the detailed description

Difficult airway assessment is based on various anatomic parameters of upper airway, much of it being concentrated on oral cavity and the pharyngeal structures. The diagnostic value of tests based on neck anatomy in predicting difficult laryngoscopy was assessed in this study .

The sample consisted of adult patients scheduled to receive general anaesthesia. Anatomic features of the neck were measured pre-operatively.

The anatomic features of the neck measured were thyromental distance, sternomental distance, ratio of height to thyromental, neck circumference, thyrosternal distance, hyomental distance at full head extension (FHE) and at neutral position (NP), ratio of neck circumference to thyromental distance and ratio of hyomental distance FHE to hyomental distance NP. The commonly used predictive tests head extension, mouth opening, upper lip bite test and Mallampati class were also measured.

The laryngoscopic view was classified according to the Cormack-Lehane Grade (1-4). Difficult laryngoscopy was defined as Cormack-Lehane Grade 3 or 4. Years of experience of the anaesthesiologists were recorded, as well as the number of tries needed to intubate the patient.

The optimal cut-off points for each predictive tests were identified by using receiver operating characteristic analysis. Sensitivity, specificity and positive predictive value and negative predictive value (NPV) were calculated for each test. Multivariate analysis with logistic regression, including all variables, was used to create a predictive model. Comparisons between genders were also performed to explore possible differences in diagnostic value and cut-off points. Finally, the years of experience of the clinician and the number of tries needed to intubate the patient were compared to assess risk of bias.

Keywords
difficult laryngoscopy, neck circumference, sternomental distance, thyromental distance, hyomental distance, thyrosternal distance

What is being measured

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

  1. Difficult laryngoscopy classification using Cormack-Lehane Grade

    Assessment of difficult laryngoscopy at the time of the airway management procedure. Classified as Grade I - visualization of entire laryngeal aperture, grade II - visualization of only posterior commissure of laryngeal aperture, grade III - visualization of only epiglottis, grade IV - visualization of just the soft palate.

    Measured: immediate

Secondary outcomes (13)

  1. Thyromental distance measured in cm with a measuring tape

    The distance from the mentum to the thyroid notch while the patient's neck is fully extended and the mouth closed

    Measured: immediate

  2. Sternomental distance measured in cm with a measuring tape

    The distance from the suprasternal notch to the mentum while the patient's neck is fully extended and the mouth closed

    Measured: immediate

  3. Ratio of height to thyromental distance

    Calculated ratio of the height in cm to the aforementioned thyromental distance

    Measured: immediate

  4. Thyrosternal distance calculated in cm

    Calculated from the subtraction: sternomental (cm) minus thyromental (cm)

    Measured: immediate

  5. Neck circumference measured in cm with a measuring tape

    Measurement at the level of the cricoid cartilage while the patient's neck is in neutral position

    Measured: immediate

  6. Ratio of neck circumference to thyromental distance

    Calculated ratio of the neck circumference to the aforementioned thyromental distance

    Measured: immediate

  7. Hyomental distance at full head extension (FHE) measured in cm with a measuring tape

    The distance from the mentum to the hyoid bone while the patient's neck is fully extended and the mouth closed

    Measured: immediate

  8. Hyomental distance at neutral position (NP) measured in cm with a measuring tape

    The distance from the mentum to the hyoid bone while the patient's neck is in neutral position and the mouth closed

    Measured: immediate

  9. Ratio of hyomental distance at FHE to hyomental distance at NP

    Calculated ratio of the aforementioned variables

    Measured: immediate

  10. Mallampati class

    Classified as class I - soft palate, fauces, uvula, and pillars seen, class II - soft palate, fauces, and uvula seen, class III - soft palate and base of uvula seen and class IV - soft palate not visible.

    Measured: immediate

  11. Mouth opening measured in cm with a measuring tape

    The distance between the upper and lower incisors with the mouth fully open

    Measured: immediate

  12. Upper lip bite test

    Classified as class I - lower incisors can bite the upper lip above the vermilion line, class II - lower incisors can bite the upper lip below the vermilion line and class III - lower incisors cannot bite the upper lip.

    Measured: immediate

  13. Head extension measured in degrees with goniometer

    The patient was asked to hold head erect, facing directly to the front, then asked to extend the head maximally and the examiner estimated the angle traversed by the occlusal surface of upper teeth using a goniometer.

    Measured: immediate

Timeline

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

  1. First posted7 Nov 2016 (estimated)
  2. Study startMar 2013
  3. Primary completionDec 2014
  4. Study completionDec 2014

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
Cohort
Time perspective
Prospective
Enrolment
1,142 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT02957084
Sponsor's protocol ID
10634
Status last verified
Nov 2016
First submitted
29 Oct 2016
Last updated
7 Nov 2016
Results posted
No
Data monitoring committee
No
Individual data sharing
No

Publications

  • Frova G, Sorbello M. Algorithms for difficult airway management: a review. Minerva Anestesiol. 2009 Apr;75(4):201-9. Epub 2008 Oct 23.

    PubMed 18946426

  • Cheney FW. The American Society of Anesthesiologists Closed Claims Project: what have we learned, how has it affected practice, and how will it affect practice in the future? Anesthesiology. 1999 Aug;91(2):552-6. doi: 10.1097/00000542-199908000-00030. No abstract available.

    PubMed 10443619

  • Chipas A, Ellis W, Zaglaniczny K. Airway management. In: Zaglaniczny K, Nagelhout J. Nurse Anesthesia. 3rd edition. USA: Elsevier Saunders; 2004:408

  • Crosby ET, Cooper RM, Douglas MJ, Doyle DJ, Hung OR, Labrecque P, Muir H, Murphy MF, Preston RP, Rose DK, Roy L. The unanticipated difficult airway with recommendations for management. Can J Anaesth. 1998 Aug;45(8):757-76. doi: 10.1007/BF03012147.

    PubMed 9793666

  • Lundstrom LH. Detection of risk factors for difficult tracheal intubation. Dan Med J. 2012 Apr;59(4):B4431.

    PubMed 22459727

  • Peterson GN, Domino KB, Caplan RA, Posner KL, Lee LA, Cheney FW. Management of the difficult airway: a closed claims analysis. Anesthesiology. 2005 Jul;103(1):33-9. doi: 10.1097/00000542-200507000-00009.

    PubMed 15983454

  • Rucker JC, Cole D, Guerina LR, Zoran N, Chung F, Friedman Z. A prospective observational evaluation of an anatomically guided, logically formulated airway measure to predict difficult laryngoscopy. Eur J Anaesthesiol. 2012 May;29(5):213-7. doi: 10.1097/EJA.0b013e3283502168.

    PubMed 22450528

  • Shiga T, Wajima Z, Inoue T, Sakamoto A. Predicting difficult intubation in apparently normal patients: a meta-analysis of bedside screening test performance. Anesthesiology. 2005 Aug;103(2):429-37. doi: 10.1097/00000542-200508000-00027.

    PubMed 16052126

  • Koay CK. Difficult tracheal intubation--analysis and management in 37 cases. Singapore Med J. 1998 Mar;39(3):112-4.

    PubMed 9632969

  • Burkle CM, Walsh MT, Harrison BA, Curry TB, Rose SH. Airway management after failure to intubate by direct laryngoscopy: outcomes in a large teaching hospital. Can J Anaesth. 2005 Jun-Jul;52(6):634-40. doi: 10.1007/BF03015776.

    PubMed 15983152

  • Cattano D, Panicucci E, Paolicchi A, Forfori F, Giunta F, Hagberg C. Risk factors assessment of the difficult airway: an italian survey of 1956 patients. Anesth Analg. 2004 Dec;99(6):1774-1779. doi: 10.1213/01.ANE.0000136772.38754.01.

    PubMed 15562070

  • Rose DK, Cohen MM. The airway: problems and predictions in 18,500 patients. Can J Anaesth. 1994 May;41(5 Pt 1):372-83. doi: 10.1007/BF03009858.

    PubMed 8055603

  • Turkan S, Ates Y, Cuhruk H, Tekdemir I. Should we reevaluate the variables for predicting the difficult airway in anesthesiology? Anesth Analg. 2002 May;94(5):1340-4, table of contents. doi: 10.1097/00000539-200205000-00055.

    PubMed 11973217

  • Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia. 1984 Nov;39(11):1105-11.

    PubMed 6507827

  • Khan ZH, Kashfi A, Ebrahimkhani E. A comparison of the upper lip bite test (a simple new technique) with modified Mallampati classification in predicting difficulty in endotracheal intubation: a prospective blinded study. Anesth Analg. 2003 Feb;96(2):595-9, table of contents. doi: 10.1097/00000539-200302000-00053.

    PubMed 12538218

Questions about this trial

What is this clinical trial studying?

An observational study of Airway Management and Predictive Value of Tests, run by National and Kapodistrian University of Athens.

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 4 inclusion and 7 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: finished, as of the sponsor's last update on 7 Nov 2016. Status can change between updates, so confirm with the study contact before making plans.

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?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Difficult laryngoscopy classification using Cormack-Lehane Grade (time frame: immediate). 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 NCT02957084, which also lists 22 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 7 Nov 2016.

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