Comparison of different video laryngoscopes for emergency intubation in a standardized airway manikin with immobilized cervical spine by experienced anaesthetists. A randomized, controlled crossover trial.

Background: The aim of the present study was to evaluate whether different video laryngoscopes (VLs) facilitate endotracheal intubation (ETI) faster or more secure than conventional laryngoscopy in a manikin with immobilized cervical spine.

Methods: After local ethics board approval, a standard airway manikin with cervical spine immobilization by means of a standard stiff collar was placed on a trauma stretcher. We compared times until glottic view, ETI, cuff block and first ventilation were achieved, and verified the endotracheal tube position, when using Macintosh laryngoscope, Glidescope Ranger, Storz C-MAC, Ambu Pentax AWS, Airtraq, and McGrath Series5 VLs in randomized order. Wilcoxon signed-rank test and McNemar's test were used for statistical analysis; p<0.05 was considered as significant.

Results: Twenty-three anaesthetists (mean age 32.1±4.9 years, mean experience in anaesthesia of 6.9±4.8 years) routinely involved in the management of multitrauma patients participated. The primary study end point, time to first effective ventilation, was achieved fastest when using Macintosh laryngoscope (21.0±7.6s) and was significantly slower with all other devices (Airtraq 33.2±23.9 s, p=0.002; Pentax AirwayScope 32.4±14.9 s, p=0.001; Storz C-MAC 34.1±23.9 s, p<0.001; McGrath Series5 101.7±108.3 s, p<0.001; Glidescope Ranger 46.3±59.1 s, p=0.001). Overall success rates were highest when using Macintosh, Airtraq and Storz C-MAC devices (100%), and were lower in Ambu Pentax AWS and Glidescope Ranger (87%, p=0.5) and in McGrath Series5 device (72.2%, p=0.063).

Conclusion: When used by experienced anaesthesiologists, video laryngoscopes did not facilitate endotracheal intubation in this model with an immobilized cervical spine in a faster or more secure way than conventional laryngoscopy. However, data was gathered in a standardized model and further studies in real trauma patients are desirable to verify our findings.