CMAC® Versus Airtraq® and Macintosh Laryngoscope in Difficult Tracheal Intubation.

Study Overview
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Brief Summary
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It is essential that anaesthetists successfully perform orotracheal intubation in scenarios in which intubation is potentially more difficult, such as where anatomical characteristics predictive of difficult intubation are present. The CMAC® Laryngoscope is a new intubating device. It is designed to provide a view of the glottis without alignment of the oral, pharyngeal and tracheal axes. The CMAC may be especially effective in situations where intubation of the trachea is potentially difficult. The efficacy of this device in comparison to the traditional Macintosh laryngoscope and other novel laryngoscopes is not known. We aim to compare its performance to that of the Macintosh laryngoscope, the gold standard device, in patients with one or more anatomical characteristics predictive of difficult intubation. The investigators further aim to compare it to the Airtraq® device a device which has been shown to be superior to the Macintosh laryngoscope in previous trials. The investigators primary hypothesis is that, in the hands of experienced anaesthetists, time to intubation would be shorter using the CMAC than using the Macintosh laryngoscope in patients with two or more anatomical characteristics predictive of difficult intubation. The investigators further hypothesize that the Airtraq® will be superior the CMAC® with one or more anatomical characteristics predictive of difficult intubation.

Official Title
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Comparison of the CMAC® Device to the Airtraq® and the Macintosh Laryngoscope in Patients With Anatomical Characteristics Predictive of Difficult Tracheal Intubation.

Conditions
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Airway, Difficult Intubation, Airway Device

Intervention / Treatment
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* Device: macintosh laryngoscope
* Device: C-MAC laryngoscope
* Device: Airtraq device


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA 1-3 patients undergoing surgical procedures requiring orotracheal intubation. Written informed Consent No relevant drug allergies Patients with 2 or more of the following predictors of difficult intubation: Mallampatti II - IV Thyromental distance < 6cm Mouth opening < 3.5 cm Cervical spine disease Anteriorly protruding incisors Presence of Caps or Crowns Exclusion Criteria: Patients with history of or risk factors for gastric regurgitation Patients unable to consent for the trial

Ages Eligible for Study
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Minimum Age: 18 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: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: macintosh<br> | Device: macintosh laryngoscope<br>* intubate with the macintosh laryngoscope<br>|
| Active Comparator: C-MAC<br> | Device: C-MAC laryngoscope<br>* intubate with the C-MAC laryngoscope<br>|
| Active Comparator: Airtraq<br> | Device: Airtraq device<br>* intubate with the Airtraq device<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of successful placement of Tube in the Trachea |  | immediately | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 1. Duration of Intubation attempt (successful Attempts only) a. Absolute time taken to perform successful tracheal intubation b. Number of successful intubations completed within 30 seconds |  | immediately | 
| 2. Tracheal Intubation attempts. a. Overall number of attempts at Intubation. b. Number of successful intubations on first attempt |  | immediately | 
| 3. Laryngeal View Obtained c. Cormac and Lehane Grading of Best Laryngeal View d. Change in view compared to initial assessment by independent anaesthetist. e. POGO score. |  | immediately |