Open Access Open Badges Study protocol

SWIVIT - Swiss video-intubation trial evaluating video-laryngoscopes in a simulated difficult airway scenario: study protocol for a multicenter prospective randomized controlled trial in Switzerland

Lorenz Theiler1*, Kristina Hermann1, Patrick Schoettker2, Georges Savoldelli3, Natalie Urwyler1, Maren Kleine-Brueggeney1, Kristopher L Arheart4 and Robert Greif1

Author Affiliations

1 University Department of Anesthesiology and Pain Therapy, University Hospital of Bern, Inselspital, Bern, 3010, Switzerland

2 Anesthesiology Department, University Hospital Center and University of Lausanne, CHUV, Lausanne, 1011, Switzerland

3 Division of Anesthesiology, University Hospitals of Geneva and Faculty of Medicine, University of Geneva, Geneva, 1211, Switzerland

4 Division of Biostatistics, Department of Epidemiology and Public Health, University of Miami, Miami, FL, 33136, USA

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Trials 2013, 14:94  doi:10.1186/1745-6215-14-94

Published: 4 April 2013



Video-laryngoscopes are marketed for intubation in difficult airway management. They provide a better view of the larynx and may facilitate tracheal intubation, but there is no adequately powered study comparing different types of video-laryngoscopes in a difficult airway scenario or in a simulated difficult airway situation.


The objective of this trial is to evaluate and to compare the clinical performance of three video-laryngoscopes with a guiding channel for intubation (Airtraq™, A. P. Advance™, King Vision™) and three video-laryngoscopes without an integrated tracheal tube guidance (C-MAC™, GlideScope™, McGrath™) in a simulated difficult airway situation in surgical patients. The working hypothesis is that each video-laryngoscope provides at least a 90% first intubation success rate (lower limit of the 95% confidence interval >0.9). It is a prospective, patient-blinded, multicenter, randomized controlled trial in 720 patients who are scheduled for elective surgery under general anesthesia, requiring tracheal intubation at one of the three participating hospitals. A difficult airway will be created using an extrication collar and taping the patients’ head on the operating table to substantially reduce mouth opening and to minimize neck movement. Tracheal intubation will be performed with the help of one of the six devices according to randomization. Insertion success, time necessary for intubation, Cormack-Lehane grade and percentage of glottic opening (POGO) score at laryngoscopy, optimization maneuvers required to aid tracheal intubation, adverse events and technical problems will be recorded. Primary outcome is intubation success at first attempt.


We will simulate the difficult airway and evaluate different video-laryngoscopes in this highly realistic and clinically challenging scenario, independently from manufacturers of the devices. Because of the sufficiently powered multicenter design this study will deliver important and cutting-edge results that will help clinicians decide which device to use for intubation of the expected and unexpected difficult airway.

Trial registration


Video-laryngoscope; Difficult airway; Airtraq; A. P. Advance; C-MAC; Glidescope; King vision; Mcgrath