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.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
DOUBLE
Enrollment
2,855
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.
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.
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.
University Hospital Wuerzburg
Würzburg, Germany
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.
Time frame: 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)
Parameters regarding the duration of the intervention
Time to intubation and time to glottis view (as announced by the anesthesist)
Time frame: 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)
Time frame: 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.
Time frame: 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)
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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)
Time frame: 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).
Time frame: 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
Time frame: 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
Time frame: 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.
Time frame: End of surgery until two hours after the end of surgery