Clinical trial NCT02957084: Anatomic Features of the Neck and Preoperative Tests as Predictive Markers of Difficult Laryngoscopy
Official title: Anatomic Features of the Neck and Preoperative Tests as Predictive Markers of Difficult Direct Laryngoscopy
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Airway Management
Predictive Value of Tests
Keywords: difficult laryngoscopy
neck circumference
sternomental distance
thyromental distance
hyomental distance
thyrosternal distance
Lead sponsor: National and Kapodistrian University of Athens
Sponsor class: OTHER
First posted: 2016-11-06
Enrollment: 1142
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
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.

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.

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.

Eligibility 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

Primary outcomes:
measure: Difficult laryngoscopy classification using Cormack-Lehane Grade
timeFrame: immediate
Secondary outcomes:
measure: Thyromental distance measured in cm with a measuring tape
timeFrame: immediate
measure: Sternomental distance measured in cm with a measuring tape
timeFrame: immediate
measure: Ratio of height to thyromental distance
timeFrame: immediate
measure: Thyrosternal distance calculated in cm
timeFrame: immediate
measure: Neck circumference measured in cm with a measuring tape
timeFrame: immediate
measure: Ratio of neck circumference to thyromental distance
timeFrame: immediate
measure: Hyomental distance at full head extension (FHE) measured in cm with a measuring tape
timeFrame: immediate
measure: Hyomental distance at neutral position (NP) measured in cm with a measuring tape
timeFrame: immediate
measure: Ratio of hyomental distance at FHE to hyomental distance at NP
timeFrame: immediate
measure: Mallampati class
timeFrame: immediate
measure: Mouth opening measured in cm with a measuring tape
timeFrame: immediate
measure: Upper lip bite test
timeFrame: immediate
measure: Head extension measured in degrees with goniometer
timeFrame: immediate
Other outcomes:
Locations:
Study officials:
affiliation: National and Kapodistrian University of Athens, 1st Department of Anaesthesia, Aretaieio Hospital
name: Chryssoula Staikou, MD, PhD, Assistant Professor
role: STUDY_DIRECTOR
References:
citation: Frova G, Sorbello M. Algorithms for difficult airway management: a review. Minerva Anestesiol. 2009 Apr;75(4):201-9. Epub 2008 Oct 23.
citation: 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.
citation: Chipas A, Ellis W, Zaglaniczny K. Airway management. In: Zaglaniczny K, Nagelhout J. Nurse Anesthesia. 3rd edition. USA: Elsevier Saunders; 2004:408
citation: 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.
citation: Lundstrom LH. Detection of risk factors for difficult tracheal intubation. Dan Med J. 2012 Apr;59(4):B4431.
citation: 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.
citation: 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.
citation: 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.
citation: Koay CK. Difficult tracheal intubation--analysis and management in 37 cases. Singapore Med J. 1998 Mar;39(3):112-4.
citation: 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.
citation: 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.
citation: 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.
citation: 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.
citation: Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia. 1984 Nov;39(11):1105-11.
citation: 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.
citation: Patil VU, Stehling LC, Zauder HL. Predicting the difficulty of intubation utilizing an intubation gauge. Anesthesiol Rev. 1983;10:32-3.
citation: Savva D. Prediction of difficult tracheal intubation. Br J Anaesth. 1994 Aug;73(2):149-53. doi: 10.1093/bja/73.2.149.
citation: Naguib M, Malabarey T, AlSatli RA, Al Damegh S, Samarkandi AH. Predictive models for difficult laryngoscopy and intubation. A clinical, radiologic and three-dimensional computer imaging study. Can J Anaesth. 1999 Aug;46(8):748-59. doi: 10.1007/BF03013910.
citation: Gupta S, Sharma R, Jain D. Airway assessment: predictors of difficult airway. Indian J Anaesth. 2005:49(4):257-62
citation: Schmitt HJ, Kirmse M, Radespiel-Troger M. Ratio of patient's height to thyromental distance improves prediction of difficult laryngoscopy. Anaesth Intensive Care. 2002 Dec;30(6):763-5. doi: 10.1177/0310057X0203000607.
citation: Huh J, Shin HY, Kim SH, Yoon TK, Kim DK. Diagnostic predictor of difficult laryngoscopy: the hyomental distance ratio. Anesth Analg. 2009 Feb;108(2):544-8. doi: 10.1213/ane.0b013e31818fc347.
citation: Greek Society for Airway management, Basic and Advanced Management of the Airway, 2nd edition, Athens, 2011