Epiglottic Downfolding During Endotracheal Intubation

Study Overview
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Brief Summary
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Usually videolaryngoscopy using a videolaryngoscope with a classic Macintosh design is performed with the blade in the vallecula and the epiglottis elevated from the vocal cords indirectly, as in direct laryngoscopy. However, during an audit of videolaryngoscopic practice we noticed that, in obtaining the best view, clinicians frequently and inadvertently advanced the blade into the vallecula to get a better view, such that the epiglottis was downfolded and elevated directly from the vocal cords. However, a better view does not necessarily lead to higher intubation success. In this randomized, controlled trial, we want to determine the efficacy of videolaryngoscope-guided tracheal intubation using an alternative position for the blade in patients with normal airways.

Detailed Description
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Anaesthesia will be induced in the conventional matter. For patients randomized to the intervention group, when the anaesthesiologist considers the depth of anaesthesia to be sufficient, a C-MAC® videolaryngoscope (Karl Storz, Tuttlingen, Germany), will be placed into the patients mouth. The best possible view of the vocal cords will be obtained with the blade positioned normally in the vallecula anterior to the epiglottis. The epiglottis will be elevated from the vocal cords indirectly, identical with direct laryngoscopy. After this, the best possible view of the vocal cords will be obtained with the blade positioned alternatively in the vallecula posterior to the epiglottis, such that the epiglottis is downfolded and elevated directly from the vocal cords. Views will be scored in both positions using the Cormack and Lehane classification system. When correct laryngoscope positioning can't be achieved with a size 3 blade, a size 4 blade will be used. For patients not randomized to the intervention group, anaesthesia will also be induced in the conventional matter. When the anaesthesiologist considers the depth of anaesthesia to be sufficient, a C-MAC® videolaryngoscope (Karl Storz, Tuttlingen, Germany), will be placed into the patients mouth. The best possible view of the vocal cords will be obtained with the blade positioned normally in the vallecula anterior to the epiglottis. The epiglottis will be elevated from the vocal cords indirectly, identical with direct laryngoscopy. The view will be scored in this position using the Cormack and Lehane classification system. After this, the patient will be intubated. Patients will be interviewed 2 and 24 hours postoperatively about sore throat, dysphonia, dysphagia and coughing.

Official Title
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Epiglottic Downfolding During Endotracheal Intubation - An Alternative Technique to Improve Glottic Exposure and Facilitate Intubation?

Conditions
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Intubation Complication, Injury of Epiglottis

Intervention / Treatment
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* Device: C-MAC® videolaryngoscope (Karl Storz, Tuttlingen, Germany)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Informed patient consent ASA I-III Age > 18 years Elective surgery, other than head and/or neck surgery Elective surgery, duration < 1 hour in supine position Pre-operative Mallampati I-II-III Exclusion Criteria: No informed patient consent ASA IV Age < 18 years Preoperative complaints of sore throat, dysphagia, dysphonia and coughing Emergency surgery, surgery of head and/of neck Surgery during > 1 hour in other than supine position Locoregional anaesthesia Preoperative Mallampati IV Known difficult airway Bad dentition Dental crowns and/or fixed partial denture Risk of aspiration (fasted < 6 hours, gastroesophageal reflux)

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

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Control group<br>In the control group, anaesthesia will be induced in the same way as mentioned above for the intervention group. Also in this group, intubation will be achieved using a C-MAC® videolaryngoscope (Karl Storz, Tuttlingen, Germany) with a size 3 Macintosh blade. The best possible view of the glottic inlet will be scored with the blade tip positioned in the vallecula. The glottic view will be scored in this position using the Cormack and Lehane classification system. If correct laryngoscope positioning cannot be achieved with a size 3 blade, a size 4 blade will be used. Hereafter, the patient's trachea will be intubated once the optimal view of the larynx had been obtained. Intubation attempts will be scored in the same way as mentioned above for the intervention group. | |
| Experimental: Epiglottic downfolding<br>Endotracheal intubation will be achieved using a C-MAC® videolaryngoscope (Karl Storz, Tuttlingen, Germany) with a size 3 Macintosh blade. The best possible view of the glottic inlet will be scored with the blade tip positioned in the vallecula. Next, the view of the glottic inlet will be scored with the blade advanced further into the vallecula, until the epiglottis flips infero-posteriorly and becomes downfolded into the trachea. The glottic view will be scored in both positions using the Cormack and Lehane classification system. After successful intubation, the blade will slowly be withdrawn into the vallecula to elevate the epiglottis back to its normal position. | Device: C-MAC® videolaryngoscope (Karl Storz, Tuttlingen, Germany)<br>* Endotracheal intubation will be achieved using a C-MAC® videolaryngoscope (Karl Storz, Tuttlingen, Germany) with a size 3 Macintosh blade. The best possible view of the glottic inlet will be scored with the blade tip positioned in the vallecula. Next, the view of the glottic inlet will be scored with the blade advanced further into the vallecula, until the epiglottis flips infero-posteriorly and becomes downfolded into the trachea. The glottic view will be scored in both positions using the Cormack and Lehane classification system. After successful intubation, the blade will slowly be withdrawn into the vallecula to elevate the epiglottis back to its normal position.<br>* Other names: Epiglottic downfolding during endotracheal intubation;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Cormack and Lehane grade | The Cormack and Lehane grade scored in both positions of the C-MAC® videolaryngoscope and consequent success of intubation | Patients will be followed for the duration of induction of anaesthesia, an average of 10 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Discomfort | Sore throat, dysphonia, dysphagia and coughing reported by patients 2 and 24 hours postoperatively | Patients will be followed for 24 hours postoperatively | 
| Use of adjuncts | Frequency of use of a stylet, gum elastic bougie or BURP manoeuvre. | Patients will be followed for the duration of induction of anaesthesia, an average of 10 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Epiglottis, Intubation, Laryngoscopy