Comparison of Three Laryngoscopes in Difficult Laryngoscopy

Study Overview
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Brief Summary
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Tracheal intubation requires alignment of oro-pharyngeal-laryngeal axes. When these three axes are not aligned, intubation becomes difficult. In the researchers' study, the investigators simulated difficult laryngoscopy situation by using a rigid neck collar. This neck collar renders intubation difficult not only by restricting neck movement, but also reducing mouth opening. The investigators compared the performance of Macintosh, MacCoy and Airtraq laryngoscope in simulated difficult laryngoscopy using a rigid neck collar.

Detailed Description
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Airtraq laryngoscope is an optical laryngoscope which allows visualization of vocal cord as a reflected image through multiple lenses and prisms. MacCoy laryngoscope is a modification of Macintosh laryngoscope. It has a lever which, when pressed, moves its flexible tip. In the investigators' study, the researchers compared the performances of Airtraq laryngoscope with MacCoy and Macintosh laryngoscopes in simulated difficult laryngoscopy using a rigid neck collar. The researchers recruited 120 patients and randomly divided those patients into three equal groups i.e. 30 patients in each group. These three groups are 1-Airtraq, 2-MacCoy and 3-Macintosh. The researchers compared efficacy and safety in these three laryngoscopes. The researchers compared efficacy in terms of time of intubation, ease of intubation, overall success, Intubation difficulty score, visualization of vocal cord in terms of POGO (percentage of Glottic Opening) score. The researchers compared safety in terms of hemodynamic pressor response and airway trauma.

Official Title
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Comparative Evaluation of Macintosh, MacCoy and Airtraq Laryngoscope in Simulated Difficult Laryngoscopy Using Rigid Neck Collar

Conditions
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Intubation; Difficult

Intervention / Treatment
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* Device: Intubation- Macintosh laryngoscope
* Device: Intubation- MacCoy laryngoscope
* Device: Intubation- Airtraq laryngoscope


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists (ASA) physical status I and II. Posted for elective surgery requiring general anesthesia and tracheal intubation Exclusion Criteria: patients with anticipated difficult airway obese (body mass index (BMI)>30) patients patients with risk of pulmonary aspiration of gastric contents pregnant patients patients with airway distortion or trauma.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

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

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intubation with Macintosh laryngoscope<br>40 patients were intubated with Macintosh laryngoscope after simulating difficult laryngoscopy using rigid neck collar. | Device: Intubation- Macintosh laryngoscope<br>* Difficult intubation was simulated by using rigid neck collar. Then patients were intubated according to the assigned laryngoscopes. In Macintosh group, tip of the laryngoscope blade was placed in the vallecula and epiglottis was lifted. After visualization of the vocal cord, patients were intubated.<br>|
| Active Comparator: Intubation with MacCoy laryngoscope<br>40 patients were intubated with MacCoy laryngoscope after simulating difficult laryngoscopy using rigid neck collar. | Device: Intubation- MacCoy laryngoscope<br>* In MacCoy group, tip of the laryngoscope blade was placed in the vallecula and lever was pressed to flex the tip. After visualization of the vocal cord, patients were intubated.<br>|
| Active Comparator: Intubation with Airtraq laryngoscope<br>40 patients were intubated with Airtraq laryngoscope after simulating difficult laryngoscopy using rigid neck collar. | Device: Intubation- Airtraq laryngoscope<br>* In Airtraq group, the laryngoscope was loaded with endotracheal tube. Airtraq laryngoscope was inserted through midline and after visualization of image of vocal cord through its eyepiece, endotracheal tube was passed.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time of Intubation | Time of intubation is defined as the time from passing the device beyond the incisors to the confirmation of endotracheal tube placement by square wave capnograph tracings. | up to 10 minutes |