Evaluation of Difficult Airway With Ultrasonography

Study Overview
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Brief Summary
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As a result of anatomical and physiological changes in obese patients, airway management can be challenging. Ultrasound measurement of neck anterior soft tissues combined with recommended predictive tests may increase the ability to predict the difficult airway. In this study we planned to evaluate the measurement of neck anterior soft tissues by ultrasound in obese patients before anesthesia induction to anticipate difficult mask ventilation, difficult laryngoscopy, and intubation.

Detailed Description
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Patients with BMI> 30, schedule elective surgery under general anesthesia, and give consent will be included in the study. In the preoperative evaluation, demographic data of the patients, airway physical examination results (mouth opening, Mallampati score, thyromental distance, neck circumference (from thyroid cartilage level), abnormal upper tooth presence, neck movement restriction], presence of sleep apnea and STOP-BANG score will be recorded. In the patients taken on the operation table with supine position, ultrasound-guided soft tissue distances will be measured using ultrasound 6-13 Hz linear probe. The distance between the hyoid bone-skin (DSHB), the vocal cord anterior commissura-skin distance (DSAC), the minimum distance of the trachea to the skin at the level of the suprasternal notch (DST), the distance between the thyroid isthmus and the skin (DSI), and the distance between the epiglottis and the skin (DSE) will be measured and recorded. After standard monitoring and anesthesia induction, difficult mask ventilation will be evaluated with Han Scale [(1) can be ventilated with a mask; 2) can be ventilated with the airway (with or without muscle relaxation); 3) difficult mask ventilation (insufficient, unstable, two practitioners are needed); 4) cannot be ventilated by mask] and grade 3-4 will be recorded as difficult mask ventilation. Difficult laryngoscopy will be evaluated with Cormack Lehane Scale [grade 1: vocal cords appear; grade-2: posterior commissura and epiglottis visible; grade-3: only epiglottis are seen; grade-4: glottic structures are not visible] and grade 3-4 will be recorded as difficult laryngoscopy. Difficult intubation will also be evaluated with the number and duration of intubation attempts with the Macintosh blade. Tracheal intubation will be performed by an anesthesiologist who has at least two years of experience and unaware of ultrasound measurements. The duration of intubation (the time from the first handling of the laryngoscope until the capnography trace appeared) and the number of trials will be recorded.

Official Title
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Evaluation of Difficult Airway in Obese Patients With Ultrasonography

Conditions
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Difficult Intubation, Obesity

Intervention / Treatment
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* Diagnostic Test: Distance between hyoid bone-skin (DSHB)
* Diagnostic Test: Vocal cord anterior commissura-skin distance (DSAC)
* Diagnostic Test: minimum distance of the trachea to the skin at the level of suprasternal notch
* Diagnostic Test: Thyroid isthmus-skin distance (DSI)
* Diagnostic Test: Skin-epiglottic distance (DSE)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients planned to undergo general anesthesia for elective surgery American Anesthesiology Association physical classification (ASA) status I-III Body mass index (BMI) above 30 Exclusion Criteria: Patients with neck mass History of previous neck and thyroid surgery, trauma, arthritis, loss of teeth History of difficult intubation Bearded patients Pregnant women

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Obese patients<br>Obese patients with BMI>30 | Diagnostic Test: Distance between hyoid bone-skin (DSHB)<br>* Distance between hyoid bone-skin<br>* Other names: DSHB;Diagnostic Test: Vocal cord anterior commissura-skin distance (DSAC)<br>* Vocal cord anterior commissura-skin distance<br>* Other names: DSAC;Diagnostic Test: minimum distance of the trachea to the skin at the level of suprasternal notch<br>* Distance of the trachea to the skin at the level of suprasternal notch<br>* Other names: DST;Diagnostic Test: Thyroid isthmus-skin distance (DSI)<br>* Thyroid isthmus-skin distance<br>* Other names: DSI;Diagnostic Test: Skin-epiglottic distance (DSE)<br>* Skin-epiglottic distance<br>* Other names: DSE;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difficult Mask Ventilation | Difficult mask ventilation will be evaluated with Han scale [(1) can be ventilated with a mask; 2) can be ventilated with the airway (with or without muscle relaxation); 3) difficult mask ventilation (insufficient, unstable, two practitioners are needed); 4) cannot be ventilated by mask] and grade 3-4 will be recorded as difficult mask ventilation. | ''1 minute'' (During anesthesia induction) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difficult laryngoscopy | Difficult laryngoscopy will be evaluated Cormack Lehane Scale [grade 1: vocal cords appear; grade-2: posterior commissura and epiglottis visible; grade-3: only epiglottis are seen; grade-4: glottic structures are not visible] and grade 3-4 will be recorded as difficult laryngoscopy. | ''1 minute'' | 
| Difficult intubation | Total number of intubation attempts | ''1 minute'' | 
| The duration of endotracheal intubation time | The time from the first handling of the laryngoscope until the capnography trace appeared | 1 minute | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Difficult mask, Difficult laryngoscopy, Difficult intubation