Forces on Teeth During Videolaryngoscopy

Study Overview
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Brief Summary
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In this randomized crossover trial the investigators test whether three different brands of videolaryngoscopes (VLS) exhibit reduced forces on both upper and lower teeth, and compare them with a classic Macintosh laryngoscope blade.

Detailed Description
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During endotracheal intubation the anesthesiologist uses a laryngoscope blade to distract the tongue to achieve the best view of the glottis opening, thereby avoiding using the maxillary incisors as a fulcrum to lever the soft tissues upwards. Using the maxillary incisors as a fulcrum may otherwise result in dental trauma. It is obvious that contact with teeth and - even worse - the incidence of accidental dental trauma, is directly related to the difficulty of the intubation. Indirect videolaryngoscopy has proven advantageous over direct laryngoscopy using a classic Macintosh blade, for improved viewing of the glottis, with subsequent more successful intubations, and a shorter effective airway time both in patients with normal and difficult airways. Previously, it has been demonstrated that the forces exerted by the anesthesiologist on the patient's maxillary incisors are reduced when using a VLS, compared with a classic Macintosh laryngoscope. However, only one type of VLS (V-MAC®, Karl Storz, Tuttlingen, Germany) was used or only forces applied to upper teeth were being registered.

Official Title
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Forces Exerted on Upper and Lower Teeth During Intubation: a Randomized, Cross-over Trial Comparing Indirect Videolaryngoscopy to Direct Videolaryngoscopy.

Conditions
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Tooth Injuries, Intubation Complication

Intervention / Treatment
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* Device: Forces exerted on teeth during intubation


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 throat surgery Pre-operative Mallampati I -III Fasted (≥6 hours) Exclusion Criteria: No informed patient consent ASA ≥ IV Age < 18 year Emergency surgery, surgery of head and/of throat Locoregional anaesthesia Pre-operative Mallampati IV Fasted < 6 hours Pre-operative expected difficult airway No teeth, bad dentition Dental crowns and/or fixed partial denture

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: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Classic Macintosh laryngoscope<br>Classic Macintosh laryngoscope (Karl Storz, Tuttlingen, Germany) | Device: Forces exerted on teeth during intubation<br>* Anesthesia will be induced in the conventional matter. The classic Macintosh laryngoscope will be placed in the patient's mouth and a tube will be brought into position in front of the glottis. Hereafter, one of the three videolaryngoscopes will be placed in the patient's mouth and the endotracheal tube will be actually passed through the vocal cords. The measurement of forces applied to the teeth will be performed using Flexiforce® sensors.<br>* Other names: Flexiforce® sensors (A201-25, Tekscan, MA, USA);|
| Other: McGrath®<br>McGrath® (Aircraft Medical Ltd, Edinburgh, UK) | Device: Forces exerted on teeth during intubation<br>* Anesthesia will be induced in the conventional matter. The classic Macintosh laryngoscope will be placed in the patient's mouth and a tube will be brought into position in front of the glottis. Hereafter, one of the three videolaryngoscopes will be placed in the patient's mouth and the endotracheal tube will be actually passed through the vocal cords. The measurement of forces applied to the teeth will be performed using Flexiforce® sensors.<br>* Other names: Flexiforce® sensors (A201-25, Tekscan, MA, USA);|
| Other: C-MAC®<br>C-MAC® (Karl Storz, Tuttlingen, Germany) | Device: Forces exerted on teeth during intubation<br>* Anesthesia will be induced in the conventional matter. The classic Macintosh laryngoscope will be placed in the patient's mouth and a tube will be brought into position in front of the glottis. Hereafter, one of the three videolaryngoscopes will be placed in the patient's mouth and the endotracheal tube will be actually passed through the vocal cords. The measurement of forces applied to the teeth will be performed using Flexiforce® sensors.<br>* Other names: Flexiforce® sensors (A201-25, Tekscan, MA, USA);|
| Other: GlideScope® Cobalt<br>GlideScope® Cobalt (Verathon Medical, Bothell, WA, USA) | Device: Forces exerted on teeth during intubation<br>* Anesthesia will be induced in the conventional matter. The classic Macintosh laryngoscope will be placed in the patient's mouth and a tube will be brought into position in front of the glottis. Hereafter, one of the three videolaryngoscopes will be placed in the patient's mouth and the endotracheal tube will be actually passed through the vocal cords. The measurement of forces applied to the teeth will be performed using Flexiforce® sensors.<br>* Other names: Flexiforce® sensors (A201-25, Tekscan, MA, USA);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measuring the frequency with which forces are applied to the upper and lower teeth. | One of the three videolaryngoscopes will be placed in the patient's mouth. The measurement of forces applied to the teeth will be performed using Flexiforce® sensors. | At intubation of the patient | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measuring the magnitude of the forces being applied and registering the differences between (video)laryngoscopes. |  | At intubation of the patient | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Forces, Videolaryngoscopy, Teeth