Conventional vs. Video-Assisted Laryngoscopy for Perioperative Endotracheal Intubation

Study Overview
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Brief Summary
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COVALENT is a randomized, controlled, multi-center study that aims to evaluate the clinical routine practice of endotracheal intubation in an operative setting comparing video-assisted laryngoscopy to direct laryngoscopy.

Detailed Description
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Data on the routine use of video-assisted laryngoscopy in peri-operative intubations are rather inconsistent and ambiguous, in part due to small study populations and non-uniform outcome measures in past trials. Failed or prolonged intubation procedures are a reason for relevant morbidity and mortality. This study aims to determine whether video-assisted laryngoscopy (irrespective of the shape of the blade) is non-inferior to the standard method of direct laryngoscopy with respect to the first-pass success rate. Furthermore, validated tools from the field of human factors will be applied to examine within-team communication and task load during this critical medical procedure.

Official Title
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Conventional vs. Video-Assisted Laryngoscopy for Perioperative Endotracheal Intubation

Conditions
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Endotracheal Intubation

Intervention / Treatment
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* Procedure: Conventional direct laryngoscopy (CDL)
* Procedure: Video assisted laryngoscopy with Macintosh-shaped blade (M-VAL)
* Procedure: Video assisted laryngoscopy with hyper-angulated blade (H-VAL)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult, legally competent patients Scheduled for elective, non-cardiac surgical procedure Need for endotracheal intubation as determined during the premedication visit Informed consent Care providers performing the intubation have at least one year of training in anesthesiology and experience in the use of VAL Exclusion Criteria: Lack of ability to give consent Previous participation in this study Pregnancy Need for fiberoptic intubation Patients scheduled for bariatric surgery Any circumstance that will lead the anesthesiologist(s) in charge to believe that random assignment of a laryngoscopy instrument may compromise patient safety during induction of anesthesia

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: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: In this randomized, controlled, three-armed parallel group design, multi-center trial, a total of more than 2500 adult patients scheduled for perioperative endotracheal intubation will be randomized. In equally large arms, video-assisted laryngoscopy with a Macintosh-shaped or a hyperangulated blade will be compared to the standard of care (direct laryngoscopy with Macintosh blade).
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: CDL<br>Conventional direct laryngoscopy using a Macintosh blade | Procedure: Conventional direct laryngoscopy (CDL)<br>* This procedure is considered the gold standard for endotracheal intubation and is routinely used in the peri-operative setting as well as in intensive care and emergency medicine.<br>* Other names: conventional laryngoscopy;|
| Experimental: M-VAL<br>Video assisted laryngoscopy with a Macintosh-shaped blade | Procedure: Video assisted laryngoscopy with Macintosh-shaped blade (M-VAL)<br>* This device is implemented in most german hospitals and used when conventional direct laryngoscopy is not sufficient. By positioning the camera at the tip of the blade, the achievable field of view onto the glottic plane is improved.<br>* Other names: video assisted laryngoscopy with Macintosh-shaped blade;|
| Experimental: H-VAL<br>Video assisted laryngoscopy with a hyper-angulated blade | Procedure: Video assisted laryngoscopy with hyper-angulated blade (H-VAL)<br>* The hyper-angulated blades are often used as a backup instrument when a view of the glottic plane cannot be achieved with the Macintosh blade due to anatomic abnormalities, even with a video-assisted laryngoscope.<br>* Other names: video assisted laryngoscopy with hyper-angulated blade;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Successful intubation | The primary endpoint is the successful intubation at first attempt as a dichotomous (successful/unsuccessful) event. The first attempt begins with the laryngoscope spatula passing the patient's row of teeth. The attempt is considered unsuccessful if a complete retraction of the laryngoscope or the endotracheal tube from the oropharynx is necessary for any reason (need for bag ventilation, change of device, change of patient position, change in the curvature of the stylet, etc.). Maneuvers that can be performed during laryngoscopy, such as BURP (backward, upward, rightward pressure) or reclining the head, which end with successful intubation, count towards the first attempt. | During the period of intubation (as soon as the laryngoscope blade passes the teeth row of the patient until the first capnographic end-expiratory carbon dioxide [CO2] detection is possible) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Parameters regarding the duration of the intervention | Time to intubation and time to glottis view (as announced by the anesthesist) | During the period of intubation (as soon as the laryngoscope blade passes the teeth row of the patient until the first capnographic end-expiratory CO2 detection is possible) | 
| Cormack & Lehane grade | Grade 1 (full view of glottis), Grade 2a (partial view of glottis), Grade 2b (view only of posterior extremity of glottis or arytenoid cartilages), Grade 3 (view of epiglottis, none of the glottis), Grade 4 (neither view of glottis nor epiglottis) | During the period of intubation (as soon as the laryngoscope blade passes the teeth row of the patient until the first capnographic end-expiratory CO2 detection is possible) | 
| Intubation success | Total number of attempts. Number of attempts using the randomized device. Success rate of intubation attempts regarding the respective device. | During the period of intubation (as soon as the laryngoscope blade passes the teeth row of the patient for the first time until the first capnographic end-expiratory CO2 detection is possible) | 
| Influence of the device on human factors during the intervention | Mayo High Performance Teamwork Scale, NASA-TLX (National Aeronautics and Space Administration's Task Load Index) | During the period of intubation and maintenance of anesthesia | 
| Complications: occurrence of one or more of the following | Drop of SpO2 (oxygen saturation) below 90%. Regurgitation as announced by the anesthetist. Need for bronchoscopy due to suspected aspiration. Dental injury or dental clicks upon contact with the blade. Soft tissue injuries as detected by blood on the blade. Visible swelling. Bleeding or other injury of the lips. Need for resuscitation (administration of adrenalin, chest compressions, defibrillation or any combination thereof). Death. Occurence of any adverse event (AE) or serious adverse event (SAE). | During the period of intubation (as soon as the laryngoscope blade passes the teeth row of the patient for the first time until the first capnographic end-expiratory CO2 detection is possible) | 
| Need for auxiliary devices or switch of laryngoscopy device | Manœuvres to optimize intubation conditions after the first attempt at intubation has started. Switch to alternate laryngoscopy device. Switch of the anesthetists. Switch of airway device | During the period of intubation (as soon as the laryngoscope blade passes the teeth row of the patient for the first time until the first capnographic end-expiratory CO2 detection is possible) | 
| Relevant vital parameters during the intervention | Baseline SpO2 and lowest SpO2 | During the period of intubation (as soon as the laryngoscope blade passes the teeth row of the patient for the first time until the first capnographic end-expiratory CO2 detection is possible) | 
| Post-operative sore throat, coughing or hoarseness | Post-operative sore throat, coughing or hoarseness, according to the Scoring System for Sore Throat, Cough, and Hoarseness by Park et al. This outcome will not be assessed in patients who continue to be invasively ventilated > 2 hours after surgery. | End of surgery until two hours after the end of surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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anesthesiology, laryngoscopy, video-assisted laryngoscopy, intubation, airway management, patient safety, human factors, conventional laryngoscopy