Learning curve and performance in simulated difficult airway for the novel C-MAC® video-stylet and C-MAC® Macintosh video laryngoscope: A prospective randomized manikin trial

Abstract

Difficult airways can be managed with a range of devices, with video laryngoscopes (VLs) being the most common. The C-MAC® Video-Stylet (VS; Karl-Storz Germany), a hybrid between a flexible and a rigid intubation endoscope, has been recently introduced. The aim of this study is to investigate the performance of the VS compared to a VL (C-MAC Macintosh blade, Karl-Storz Germany) with regards to the learning curve for each device and its ability to manage a simulated difficult airway manikin. This is a single-center, prospective, randomized, crossover study involving twenty-one anesthesia residents performing intubations on a Bill 1™ (VBM, Germany) airway manikin model. After a standardized introduction, six randomized attempts with VL and VS were performed on the manikin. This was followed by intubation in a simulated difficult airway (cervical collar and inflated tongue) with both devices in a randomized fashion. The primary end-point of this study was the total time to intubation. All continuous variables were expressed as the median [interquartile range] and analyzed using the Mann-Whitney U test. A 2-way ANOVA with Bonferroni’s post hoc test was used to compare both devices at each trial. All reported p values are two sided. The median total time to intubation on a simulated difficult airway was faster with the VS compared to VL (17 [13.5–25] sec vs 23 [18.5–26.5] sec, respectively; 95% CI; P = 0.031). Additionally, on a normal airway manikin, the VS has a comparable learning curve to the VL. In this manikin-based study, the novel VS was comparable to the VL in terms of learning curve in a normal airway. In a simulated difficult airway, the total time to intubation, though likely not clinically relevant, was faster with the VS to the VL. However, given the above findings, this study justifies further human clinical trials with the VS to see if similar benefits–faster time to intubation and similar learning curve to VL–are replicated clinically.

A Paradigm Shift of Airway Management: The Role of Video-Assisted Intubating Stylet Technique

“…with VL in a normal airway vs. difficult airway due to limited mouth opening mannequin-based study. However, in the difficult airway model, VS was quicker to intubate [149,218]. Similar results were reported when VS was compared with DL [64,219,220].…”

Comparison of video-stylet and conventional laryngoscope for endotracheal intubation in adults with cervical spine immobilization: A PRISMA-compliant meta-analysis

“…[ 35 ] Besides, there are specific situations where intubation with video-stylets may be advantageous over the conventional laryngoscopic approach such as difficulty in blade insertion in patients with limited oral opening [ 32 ] or the need for creating an unobstructed passageway through visualization of the vocal cords with video-stylets. [ 36 ] However, the latter does not guarantee an unobstructed path for tracheal tube insertion. [ 37 ] Although the operating principle of video-stylets is different from that of laryngoscopes, some authors reported that a steep learning curve can be achieved with video-stylets.…”

“…[ 37 ] Although the operating principle of video-stylets is different from that of laryngoscopes, some authors reported that a steep learning curve can be achieved with video-stylets. [ 36 , 38 ] Taking into account the increasing availability of video-stylets, [ 36 ] they may be incorporated into the difficult airway management algorithm to optimize patient care.…”

“…There are several limitations in the current report. First, although there are new video-stylets available in the market, [ 36 , 39 , 40 ] only 3 models of video-stylets were available for analysis in the present meta-analysis. As the design and operating principle among various video-stylets may differ, our results may not be extrapolated to other video-stylets.…”

Simulation-based airway research: The fast-track recipes?

“…Also, a variety of clinical scenarios including copious oral secretions, oropharyngeal bleeding, fogging caused by body temperature and gag reflex can be encountered in real-life clinical practice, but simulation cannot replicate these huge variations. [ 20 ]…”