Measurement of Forces Applied Using a Macintosh Direct Laryngoscope Compared to GlideScope Video Laryngoscope

Study Overview
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Brief Summary
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Patients undergoing surgery or intensive care management often require a tube to be inserted into the trachea allowing lung ventilation. Usually a laryngoscope is used to allow visualisation of the larynx and facilitate intubation. During direct laryngoscopy, the blade of the laryngoscope is inserted into the patient's mouth and the structures pulled upwards out of the line of vision. If visualisation is difficult, users often exert excess force on the tissues to obtain an adequate view. Generally the applied force is evaluated by the patient's stress response such as increased heart rate, blood pressure or plasma cortisol levels. These changes, while important, may be confounded by a variety of patient factors, as well as anaesthesia. An increased force may also be associated with tissue trauma, dental damage, and prolonged attempts. The investigators' objective is to compare the force exerted on patient's tissues by the Macintosh laryngoscope and GlideScope video-laryngoscope. Video-laryngoscopes may be associated with the application of reduced force to the soft tissues of patients during intubation. While this is a common contention, it has not been proven. The GlideScope has a micro camera in the distal portion of the blade meaning a direct line of vision is not required. An adequate view can therefore be obtained with less displacement of tongue tissue. If the force exerted by the video laryngoscope is less, this would have beneficial implications by reducing stress response, neck movement, and trauma.

Official Title
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Measurement of Forces Applied Using a Macintosh Direct Laryngoscope Compared to GlideScope Video Laryngoscope

Conditions
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Endotracheal Intubation, Laryngoscopy

Intervention / Treatment
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* Device: Macintosh (direct vision) laryngoscope
* Device: GlideScope videolaryngoscope (indirect vision)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age > 18years ASA 1-2 elective surgery endotracheal intubation required (with non-depolarising muscle relaxant) signed informed consent Exclusion Criteria: lack of informed consent endotracheal intubation not required ASA 3-5 symptomatic gastro-oesophageal reflux rapid sequence intubation other method of intubation indicated eg fibreoptic, awake tracheostomy cervical spine instability unstable hypertension coronary artery disease cerebral disease COPD/asthma oral/pharyngeal/laryngeal carcinoma loose teeth/poor dentition Macintosh laryngoscope >size 3 required

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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Macintosh (direct vision) laryngoscope<br>Macintosh (direct vision) laryngoscope | Device: Macintosh (direct vision) laryngoscope<br>* Macintosh (direct vision) laryngoscope<br>|
| Active Comparator: GlideScope videolaryngoscope (indirect vision)<br>GlideScope videolaryngoscope (indirect vision) | Device: GlideScope videolaryngoscope (indirect vision)<br>* GlideScope videolaryngoscope (indirect vision)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Forces generated during the intubation process using both laryngoscopes including peak and mean forces. |  | 5-15minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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GlideScope Video Laryngoscope, Macintosh Direct Laryngoscope, Intubation, Applied Forces, Elective surgery where endotracheal intubation required