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

This study has been terminated.
(Insufficient Recruitment. Findings of concurrent study in low risk population not supportive of hypotheses in this study.)
Information provided by (Responsible Party):
John Laffey, University College Hospital Galway Identifier:
First received: December 14, 2009
Last updated: June 17, 2012
Last verified: June 2012

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.

Condition Intervention
Airway Difficult Intubation Airway Device Device: macintosh laryngoscope Device: C-MAC laryngoscope Device: Airtraq device

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Comparison of the CMAC® Device to the Airtraq® and the Macintosh Laryngoscope in Patients With Anatomical Characteristics Predictive of Difficult Tracheal Intubation.

Further study details as provided by John Laffey, University College Hospital Galway:

Primary Outcome Measures:
  • Rate of successful placement of Tube in the Trachea [ Time Frame: immediately ]

Secondary Outcome Measures:
  • 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 [ Time Frame: immediately ]
  • 2. Tracheal Intubation attempts. a. Overall number of attempts at Intubation. b. Number of successful intubations on first attempt [ Time Frame: 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. [ Time Frame: immediately ]

Enrollment: 15
Study Start Date: January 2010
Study Completion Date: March 2011
Primary Completion Date: March 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: macintosh Device: macintosh laryngoscope
intubate with the macintosh laryngoscope
Active Comparator: C-MAC Device: C-MAC laryngoscope
intubate with the C-MAC laryngoscope
Active Comparator: Airtraq Device: Airtraq device
intubate with the Airtraq device


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

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
  Contacts and Locations
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Please refer to this study by its identifier: NCT01031940

Galway University Hospital
Galway, Ireland
Sponsors and Collaborators
University College Hospital Galway
  More Information

Responsible Party: John Laffey, Professor of Anaesthesia, University College Hospital Galway Identifier: NCT01031940     History of Changes
Other Study ID Numbers: CMAC-1
Study First Received: December 14, 2009
Last Updated: June 17, 2012 processed this record on August 21, 2017