Anatomic Features of the Neck and Preoperative Tests as Predictive Markers of Difficult Direct Laryngoscopy
Overview
- Phase
- Not Applicable
- Intervention
- Not specified
- Conditions
- Airway Management
- Sponsor
- National and Kapodistrian University of Athens
- Enrollment
- 1142
- Primary Endpoint
- Difficult laryngoscopy classification using Cormack-Lehane Grade
- Status
- Completed
- Last Updated
- 9 years ago
Overview
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.
Investigators
Chara Liaskou
RN, Msc, Phd(c)
National and Kapodistrian University of Athens
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
Outcomes
Primary Outcomes
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 Outcomes
- Thyromental distance measured in cm with a measuring tape(immediate)
- Thyrosternal distance calculated in cm(immediate)
- Upper lip bite test(immediate)
- Head extension measured in degrees with goniometer(immediate)
- Ratio of neck circumference to thyromental distance(immediate)
- Hyomental distance at full head extension (FHE) measured in cm with a measuring tape(immediate)
- Hyomental distance at neutral position (NP) measured in cm with a measuring tape(immediate)
- Ratio of hyomental distance at FHE to hyomental distance at NP(immediate)
- Mallampati class(immediate)
- Neck circumference measured in cm with a measuring tape(immediate)
- Sternomental distance measured in cm with a measuring tape(immediate)
- Ratio of height to thyromental distance(immediate)
- Mouth opening measured in cm with a measuring tape(immediate)