Intubation; Difficult
Conditions
Keywords
laryngoscopes
Brief summary
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
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.
Interventions
DEVICEMacintosh laryngoscope
Glottis view assessment by direct visualization using Macintosh laryngoscope
DEVICEGVL selected by weight
Glottis view assessment by GVL selected by weight which is usually selected first
DEVICEsmaller sized GVL
Glottis view assessment by GVL which is smaller in one size than GVL selected by age
Sponsors
Seoul National University Hospital
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Masking
NONE
Eligibility
Sex/Gender
ALL
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| The Differences in the Glottis View (C&L Grade) of Macintosh Laryngoscope and GVL Selected by Weight. | up to 1 day of surgery | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| The Differences in the Glottis View (C&L Grade) of GVL Selected by Weight and Smaller Sized GVL | up to 1day of surgery | 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. |
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Glottis View Assessment After checking the C&L grade using Macintosh laryngoscope, C&L grade was re-evaluated using GVL selected by weight and smaller sized GVL in consecutive order. | 23 |
| Total | 23 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Smaller Sized GVL for 5 Sec | lack of GVL size | 4 |
Baseline characteristics
| Characteristic | Glottis View Assessment |
|---|---|
| Age, Categorical <=18 years | 23 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 0 Participants |
| Age, Continuous | 7.9 years STANDARD_DEVIATION 4.8 |
| Sex: Female, Male Female | 10 Participants |
| Sex: Female, Male Male | 13 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — | — / — |
| other Total, other adverse events | 0 / 23 | 0 / 23 | 0 / 19 |
| serious Total, serious adverse events | 0 / 23 | 0 / 23 | 0 / 19 |
Outcome results
Primary
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.
Time frame: up to 1 day of surgery
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Macintosh Laryngoscope | The Differences in the Glottis View (C&L Grade) of Macintosh Laryngoscope and GVL Selected by Weight. | 6 units on a scale |
| GVL Selected by Weight | The Differences in the Glottis View (C&L Grade) of Macintosh Laryngoscope and GVL Selected by Weight. | 5.5 units on a scale |
Comparison: An improvement of C\&L grade ordinal scale by 2 was considered a clinically significant change. The mean difference of C\&L grade ordinal scale between DL and GVLw was 1.3, and its standard deviation was 2.0 in our pilot study. The required sample size for the Wilcoxon signed rank test was 21 with an α error of 0.05 and 80% power.p-value: <0.05Wilcoxon (Mann-Whitney)
Secondary
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.
Time frame: up to 1day of surgery
Population: Four of 23 patients could not be evaluated by smaller sized GVL because there was no smaller blade than their GVL selected by weight.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Macintosh Laryngoscope | The Differences in the Glottis View (C&L Grade) of GVL Selected by Weight and Smaller Sized GVL | 5.5 units on a scale |
| GVL Selected by Weight | The Differences in the Glottis View (C&L Grade) of GVL Selected by Weight and Smaller Sized GVL | 1 units on a scale |
Comparison: An improvement of C\&L grade ordinal scale by 2 was considered a clinically significant change. The mean difference of C\&L grade ordinal scale between DL and GVLw was 1.3, and its standard deviation was 2.0 in our pilot study. The required sample size for the Wilcoxon signed rank test was 21 with an α error of 0.05 and 80% power.p-value: <0.05Wilcoxon (Mann-Whitney)