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

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ClinicalTrials.gov Identifier: NCT02957084
Recruitment Status : Completed
First Posted : November 7, 2016
Last Update Posted : November 7, 2016
Sponsor:
Information provided by (Responsible Party):
Chara Liaskou, National and Kapodistrian University of Athens

Brief 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 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.


Condition or disease
Airway Management Predictive Value of Tests

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.


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Study Type : Observational
Actual Enrollment : 1142 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Anatomic Features of the Neck and Preoperative Tests as Predictive Markers of Difficult Direct Laryngoscopy
Study Start Date : March 2013
Actual Primary Completion Date : December 2014
Actual Study Completion Date : December 2014



Primary Outcome Measures :
  1. Difficult laryngoscopy classification using Cormack-Lehane Grade [ Time Frame: immediate ]
    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.


Secondary Outcome Measures :
  1. Thyromental distance measured in cm with a measuring tape [ Time Frame: immediate ]
    The distance from the mentum to the thyroid notch while the patient's neck is fully extended and the mouth closed

  2. Sternomental distance measured in cm with a measuring tape [ Time Frame: immediate ]
    The distance from the suprasternal notch to the mentum while the patient's neck is fully extended and the mouth closed

  3. Ratio of height to thyromental distance [ Time Frame: immediate ]
    Calculated ratio of the height in cm to the aforementioned thyromental distance

  4. Thyrosternal distance calculated in cm [ Time Frame: immediate ]
    Calculated from the subtraction: sternomental (cm) minus thyromental (cm)

  5. Neck circumference measured in cm with a measuring tape [ Time Frame: immediate ]
    Measurement at the level of the cricoid cartilage while the patient's neck is in neutral position

  6. Ratio of neck circumference to thyromental distance [ Time Frame: immediate ]
    Calculated ratio of the neck circumference to the aforementioned thyromental distance

  7. Hyomental distance at full head extension (FHE) measured in cm with a measuring tape [ Time Frame: immediate ]
    The distance from the mentum to the hyoid bone while the patient's neck is fully extended and the mouth closed

  8. Hyomental distance at neutral position (NP) measured in cm with a measuring tape [ Time Frame: immediate ]
    The distance from the mentum to the hyoid bone while the patient's neck is in neutral position and the mouth closed

  9. Ratio of hyomental distance at FHE to hyomental distance at NP [ Time Frame: immediate ]
    Calculated ratio of the aforementioned variables

  10. Mallampati class [ Time Frame: immediate ]
    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.

  11. Mouth opening measured in cm with a measuring tape [ Time Frame: immediate ]
    The distance between the upper and lower incisors with the mouth fully open

  12. Upper lip bite test [ Time Frame: immediate ]
    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.

  13. Head extension measured in degrees with goniometer [ Time Frame: immediate ]
    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.



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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
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.
Criteria

Inclusion Criteria:

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

Exclusion Criteria:

  • 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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02957084


Sponsors and Collaborators
National and Kapodistrian University of Athens
Investigators
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Study Director: Chryssoula Staikou, MD, PhD, Assistant Professor National and Kapodistrian University of Athens, 1st Department of Anaesthesia, Aretaieio Hospital

Publications:
Chipas A, Ellis W, Zaglaniczny K. Airway management. In: Zaglaniczny K, Nagelhout J. Nurse Anesthesia. 3rd edition. USA: Elsevier Saunders; 2004:408
Patil VU, Stehling LC, Zauder HL. Predicting the difficulty of intubation utilizing an intubation gauge. Anesthesiol Rev. 1983;10:32-3.
Gupta S, Sharma R, Jain D. Airway assessment: predictors of difficult airway. Indian J Anaesth. 2005:49(4):257-62
Greek Society for Airway management, Basic and Advanced Management of the Airway, 2nd edition, Athens, 2011

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Responsible Party: Chara Liaskou, RN, Msc, Phd(c), National and Kapodistrian University of Athens
ClinicalTrials.gov Identifier: NCT02957084     History of Changes
Other Study ID Numbers: 10634
First Posted: November 7, 2016    Key Record Dates
Last Update Posted: November 7, 2016
Last Verified: November 2016
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Keywords provided by Chara Liaskou, National and Kapodistrian University of Athens:
difficult laryngoscopy
neck circumference
sternomental distance
thyromental distance
hyomental distance
thyrosternal distance