Intubation, Respiratory Failure
Conditions
Brief summary
The investigators studied the efficiency of Macintosh laryngoscope and the King Vision video laryngoscope in adult patients scheduled for general anesthesia. Best Cormack-Lehane score obtained, glottic view time, intubation time, time to ventilation, correlation between the Mallampati classification and the Cormack-Lehane grades, and complications related to laryngoscopy and intubation has been investigated.
Detailed description
Securing the airway is essential in general anesthesia. Anesthetic problems related to airway management constitute 17% of closed claims, difficult intubation being the most common one with an occurrence rate of 5%. Problems like delayed intubation, misplaced tracheal tube, or airway trauma are frequently seen in outpatient settings and end up with either death or hypoxic brain damage. Therefore, preoperative visit should include detailed assessment of the airways according to clues of difficult intubation.Several studies compared the King Vision video laryngoscope with other laryngoscopes in manikins simulating difficult airway scenarios, and reported better glottic views. The investigators aimed to study the correlation between the Mallampati classification and the glottic views (Cormack-Lehane grade) obtained with Macintosh laryngoscopy, and the King Vision video laryngoscopy in adult patients scheduled for general anesthesia. Secondary outcomes will be successful intubation rate, time to obtain the best view, time to successful intubation, and complications related to laryngoscopy will be compared.
Interventions
DEVICEMacintosh laryngoscope
Using a Macintosh laryngoscope, time to glottic view, best Cormack-Lehane grade, time to intubation, time to first ventilation has been recorded.
Using a King Vision video laryngoscope, time to glottic view, best Cormack-Lehane grade, time to intubation, time to first ventilation has been recorded.
Sponsors
Recep Tayyip Erdogan University
Study design
Allocation
RANDOMIZED
Intervention model
SEQUENTIAL
Primary purpose
OTHER
Masking
DOUBLE (Subject, Outcomes Assessor)
Intervention model description
Patients scheduled for general anesthesia with endotracheal intubation will be randomized to either intubation with Macintosh laryngoscope first or King Vision videolaryngoscope first. All patients will be intubated with both laryngoscopes.
Eligibility
Sex/Gender
ALL
Age
18 Years to 60 Years
Healthy volunteers
Yes
Inclusion criteria
* scheduled for general anesthesia * age higher than 18 years * age lower than 60 years
Exclusion criteria
* emergency surgery * mouth opening less than 2 cm * American Society of Anesthesiologists (ASA) score higher than 2 * oropharyngeal anomaly * glottic or supraglottic mass * history of surgery due to oropharyngeal anomaly, glottic or supraglottic mass
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Intubation Success Rate | less than 24 hours | Endotracheal intubation attempt is defined as entrance of the endotracheal tube into the patient's mouth. Any major change in the alignment of the laryngoscope is defined as another intubation attempt. Successful endotracheal intubation is defined as the endotracheal cuff passing through the patient's vocal cords. Intubation success rate is defined as: 1 / \[the number of attempts\]. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Intubation Time | less than 24 hours | Successful endotracheal intubation is defined as the endotracheal cuff passing the patient's vocal cords. Time to intubation with each laryngoscope is recorded. |
| Glottic View Time | less than 24 hours | Glottic view time (as defined when the laryngoscopist declared the best Cormack-Lehane score) with each laryngoscope is recorded. Cormack-Lehane score is obtained by directly assessing the distance between the base of the tongue and the roof of the mouth to predict how difficult an intubation will be. It consists of 4 grades: 1. full view of glottis (difficult intubation unlikely) 2. partial view of glottis (\ 5% risk of difficult intubation) 3. partial view of epiglottis, none of glottis seen (\ 90% risk of difficult intubation) 4. neither glottis nor epiglottis seen (difficult intubation very likely) |
| Cormack-Lehane Score | less than 24 hours | Best Cormack-Lehane score (as declared by the laryngoscopist) obtained with both laryngoscopes is recorded. Cormack-Lehane score is graded according to the following criteria (1 is best, and 4 is worst): 1. full view of glottis (difficult intubation unlikely) 2. partial view of glottis (\ 5% risk of difficult intubation) 3. partial view of epiglottis, none of glottis seen (\ 90% risk of difficult intubation) 4. neither glottis nor epiglottis seen (difficult intubation very likely) |
| Airway Complications | The participants' will be followed for the duration of hospital stay, an expected average of 2 days | Any complication related to the laryngoscopy and intubation, such as cut, bleeding, damage to the teeth, laryngospasm, bronchospasm, desaturation below 90%, is recorded. |
Countries
Turkey (Türkiye)
Participant flow
Recruitment details
This study enrolled adult patients scheduled for general anesthesia with intubation in Recep Tayyip Erdogan University Education and Research Hospital. The last patient completed in July 2014.
Pre-assignment details
None of the 388 patients enrolled between January 2014 and July 2014 were excluded from the trial.
Participants by arm
| Arm | Count |
|---|---|
| All Study Participants Each patient were intubated with both Macintosh and King Vision video laryngoscope sequentially. The order of the laryngoscopes was randomized by flipping a coin. | 388 |
| Total | 388 |
Baseline characteristics
| Characteristic | All Study Participants |
|---|---|
| Age, Continuous | 48.5 years |
| American Society of Anesthesiologists score, Categorical 1 - A normal healthy patient | 192 Participants |
| American Society of Anesthesiologists score, Categorical 2 - A patient with mild systemic disease | 196 Participants |
| Body mass index, Continuous | 26.9 kg/m^2 |
| Height, Continuous | 171 cm |
| History of obstructive sleep apnea, Categorical 0 - No history of obstructive sleep apnea | 292 Participants |
| History of obstructive sleep apnea, Categorical 1 - History of obstructive sleep apnea | 96 Participants |
| History of snoring, Categorical 0 - No history of snoring | 246 Participants |
| History of snoring, Categorical 1 - History of snoring | 142 Participants |
| Interincisor distance, Continuous | 3.3 cm |
| Mallampati class, Categorical 0 - Ability to see any part of the epiglottis | 0 Participants |
| Mallampati class, Categorical 1 - Soft palate, fauces, uvula, pillars visible | 79 Participants |
| Mallampati class, Categorical 2 - Soft palate, fauces, uvula visible | 113 Participants |
| Mallampati class, Categorical 3 - Soft palate, base of uvula visible | 107 Participants |
| Mallampati class, Categorical 4 - Soft palate not visible at all | 89 Participants |
| Sex: Female, Male Female | 158 Participants |
| Sex: Female, Male Male | 230 Participants |
| Sternomental distance, Continuous | 10.9 cm |
| Thyromental distance, Continuous | 6.2 cm |
| Weight, Continuous | 80 kg |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 6 / 202 | 4 / 186 |
| other Total, other adverse events | 3 / 202 | 3 / 186 |
| serious Total, serious adverse events | 0 / 202 | 0 / 186 |
Outcome results
Primary
Intubation Success Rate
Endotracheal intubation attempt is defined as entrance of the endotracheal tube into the patient's mouth. Any major change in the alignment of the laryngoscope is defined as another intubation attempt. Successful endotracheal intubation is defined as the endotracheal cuff passing through the patient's vocal cords. Intubation success rate is defined as: 1 / \[the number of attempts\].
Time frame: less than 24 hours
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Macintosh | Intubation Success Rate | 0 - Could not be intubated | 22 participants |
| Macintosh | Intubation Success Rate | 1 - Successfully intubated | 366 participants |
| King Vision Video Laryngoscope | Intubation Success Rate | 1 - Successfully intubated | 375 participants |
| King Vision Video Laryngoscope | Intubation Success Rate | 0 - Could not be intubated | 13 participants |
Comparison: Sample size was calculated according to the first 60 patients. To obtain 90% power with an alpha error of 0.05, a total of 378 patients were required. Considering a possible drop-out rate of 2.5% due to unexpected complications, we aimed for 388 patients.p-value: 0.119Chi-squared
Secondary
Airway Complications
Any complication related to the laryngoscopy and intubation, such as cut, bleeding, damage to the teeth, laryngospasm, bronchospasm, desaturation below 90%, is recorded.
Time frame: The participants' will be followed for the duration of hospital stay, an expected average of 2 days
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Macintosh | Airway Complications | 0 - No complication | 384 participants |
| Macintosh | Airway Complications | 1 - Minor cuts on the lips | 4 participants |
| King Vision Video Laryngoscope | Airway Complications | 0 - No complication | 382 participants |
| King Vision Video Laryngoscope | Airway Complications | 1 - Minor cuts on the lips | 6 participants |
p-value: 0.75Chi-squared, Corrected
Secondary
Cormack-Lehane Score
Best Cormack-Lehane score (as declared by the laryngoscopist) obtained with both laryngoscopes is recorded. Cormack-Lehane score is graded according to the following criteria (1 is best, and 4 is worst): 1. full view of glottis (difficult intubation unlikely) 2. partial view of glottis (\ 5% risk of difficult intubation) 3. partial view of epiglottis, none of glottis seen (\ 90% risk of difficult intubation) 4. neither glottis nor epiglottis seen (difficult intubation very likely)
Time frame: less than 24 hours
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Macintosh | Cormack-Lehane Score | 4 - No laryngeal structures are visible | 7 participants |
| Macintosh | Cormack-Lehane Score | 2 - At most half of the glottis is seen | 139 participants |
| Macintosh | Cormack-Lehane Score | 1 - Most of the glottis is visible | 149 participants |
| Macintosh | Cormack-Lehane Score | 3 - Only the epiglottis is visible | 93 participants |
| King Vision Video Laryngoscope | Cormack-Lehane Score | 1 - Most of the glottis is visible | 357 participants |
| King Vision Video Laryngoscope | Cormack-Lehane Score | 3 - Only the epiglottis is visible | 0 participants |
| King Vision Video Laryngoscope | Cormack-Lehane Score | 4 - No laryngeal structures are visible | 0 participants |
| King Vision Video Laryngoscope | Cormack-Lehane Score | 2 - At most half of the glottis is seen | 31 participants |
Comparison: For each patient, the difference between Cormack-Lehane score and Mallampati class was calculated for each laryngoscope. As an example, the first patient had a Mallampati score 3. Macintosh laryngoscope provided a Cormack-Lehane score of 2, therefore the difference is - 1, calculated as 2 - 3. In the same patient, King Vision video laryngoscope provided a Cormack-Lehane score of 1, therefore the difference is - 2, calculated as 1 - 3. T-test was used to compare the differences.p-value: <0.000195% CI: [-0.95, -0.67]t-test, 2 sided
Secondary
Glottic View Time
Glottic view time (as defined when the laryngoscopist declared the best Cormack-Lehane score) with each laryngoscope is recorded. Cormack-Lehane score is obtained by directly assessing the distance between the base of the tongue and the roof of the mouth to predict how difficult an intubation will be. It consists of 4 grades: 1. full view of glottis (difficult intubation unlikely) 2. partial view of glottis (\ 5% risk of difficult intubation) 3. partial view of epiglottis, none of glottis seen (\ 90% risk of difficult intubation) 4. neither glottis nor epiglottis seen (difficult intubation very likely)
Time frame: less than 24 hours
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Macintosh | Glottic View Time | 7.3 seconds |
| King Vision Video Laryngoscope | Glottic View Time | 7.9 seconds |
p-value: <0.000195% CI: [0.5, 1.4]Wilcoxon (Mann-Whitney)
Secondary
Intubation Time
Successful endotracheal intubation is defined as the endotracheal cuff passing the patient's vocal cords. Time to intubation with each laryngoscope is recorded.
Time frame: less than 24 hours
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Macintosh | Intubation Time | 6.6 seconds |
| King Vision Video Laryngoscope | Intubation Time | 10.8 seconds |
p-value: <0.000195% CI: [3, 4.6]Wilcoxon (Mann-Whitney)