GlideScope®Video Laryngoscope for Difficult Intubation: Implication of the Size of Blade

Study Overview
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Brief Summary
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The investigators evaluated the usefulness of the Glidescope(GVL) compared with direct laryngoscopy in patients whose airway management are anticipated difficult (C&L grade ≥3) by comparing the laryngoscopic view. Also, the investigators compared the effectiveness of smaller-size blade of GVL (GVLs) with standard blade of GVL selected by patient's weight (GVLw) in the same patients.

Detailed Description
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We assumed that smaller sized GVL can slide more angulated along the tongue, so the tip of a blade can be placed more anterior and cephalad. The angle of camera would be optimized by inserting the blade further with the blade tip directed toward the larynx. This optimization may be more remarkable with smaller blade because it can be inserted with rotation. Furthermore, the location and the angle of camera are different according to GVL blade size. Considering that patient with difficult airway has hypognathia and more cephalad larynx, it may be helpful with smaller sized GVL (GVLs) rather than GVL selected by weight (GVLw) for improvement of laryngoscopic view in patients with difficult airways. We hypothesized that GVLs can provide better laryngoscopic view than GVLw and DL in patient with difficult airway.

Official Title
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GlideScope®Video Laryngoscope for Difficult Intubation: Implication of the Size of Blade

Conditions
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Intubation; Difficult

Intervention / Treatment
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* Device: Macintosh laryngoscope
* Device: GVL selected by weight
* Device: smaller sized GVL


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients whose C&L grade were over 3 in previous anesthetic records. Exclusion Criteria: Patients with pulmonary aspiration, increased intracranial pressure, and severe cardiovascular disease
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: glottis view assessment<br>Glottis view assessment using Macintosh laryngoscope & GVL selected by weight & smaller sized GVL in single patient | Device: Macintosh laryngoscope<br>* Glottis view assessment by direct visualization using Macintosh laryngoscope<br>Device: GVL selected by weight<br>* Glottis view assessment by GVL selected by weight which is usually selected first<br>* Other names: GlideScope® videolaryngoscopy selected by weight;Device: smaller sized GVL<br>* Glottis view assessment by GVL which is smaller in one size than GVL selected by age<br>* Other names: smaller sized GlideScope® videolaryngoscopy;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Differences in the Glottis View (C&L Grade) of Macintosh Laryngoscope and GVL Selected by Weight. | Glottis view was scored using C&L grade by Macintosh laryngoscope and GVL selected by weight, and compared each other. We used modified C&L grade: grade 1, all or most of the glottic aperture was visible; grade 2a, posterior cords and cartilage visible; grade 2b, only posterior cartilage visible; grade 3a, epiglottis visible and can be lifted; grade 3b, epiglottis adherent to the posterior pharynx; and grade 4, the epiglottis could not be visualized. For the statistical analysis, the modified C&L grade was converted to an ordinal scale; grade 1 to 1, grade 2a to 2, grade 2b to 3, grade 3a to 4, grade 3b to 5, and grade 4 to 6. Therefore, score range for the data reported in the table was between 1 and 6, with 1 representing best view and 6 representing no view. | up to 1 day of surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Differences in the Glottis View (C&L Grade) of GVL Selected by Weight and Smaller Sized GVL | Glottis view was scored using C&L grade by GVL selected by weight and smaller sized GVL, and compared each other. Score range for the data reported in the table was between 1 and 6, with 1 representing best view and 6 representing no view. | up to 1day of surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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laryngoscopes