Comparison of the McGrath MAC EMS Videolaryngoscope with a Conventional Laryngoscope for Standard and Difficult Airway Intubation: A Randomized, Cross-over, Simulation Trial

Abstract

Aim: Tracheal intubation is challenging in emergency medicine, especially in pre-hospital settings, owing to problems connected with patients, intubator, and the environment. The study aimed to compare the effectiveness of endotracheal intubation performed by paramedics with the use of direct laryngoscopy and the McGrath MAC videolaryngoscope in standard and difficult airway settings. Materials and Methods: The study was designed as a prospective, randomized, cross-over simulation study. It involved 52 paramedics. The participants performed endotracheal intubation in two scenarios: Normal airway and difficult airway, achieved by inflation of the simulator tongue to the level of difficulty determined by an independent instructor at grade 3 on the Cormack-Lehane scale. The primary endpoint was the success of endotracheal intubation; intubation time constituted the secondary endpoint. Results: The median age of participants was 24 years [interquartile range (IQR): 23-25], and the median work experience was 0.5 years (IQR: 0-1). In normal airway (scenario A), the effectiveness of the first intubation attempt was 92.3% for MAC and 96.2% for McGrath (p=0.724). The median intubation time for MAC was 19 (IQR: 14-21.5) seconds and was statistically significantly longer than 16 (12.5-20) seconds for McGrath ( p=0.047). The ease of intubation was 18 (IQR: 10-20) points for McGrath and 25 (IQR: 16-27) points for MAC ( p=0.035). In difficult airway (scenario B), the efficacy of the first intubation attempt for MAC and McGrath equaled 40.4% and 82.7%, respectively. The median intubation time for McGrath was 19 (IQR: 14-27.5) seconds and was significantly shorter than 25 (IQR: 24-39) seconds for MAC ( p=0.007). The degree of glottis visualization was statistically significantly better in McGrath than in MAC (p<0.001). The ease of intubation was 25 (IQR: 20-32) points for McGrath and 49 (IQR: 34-58) points for MAC (p<0.001). Overall, 96.2% of subjects intubating in difficult airway conditions chose the McGrath videolaryngoscope as their preferred intubation method as compared with MAC. Conclusion: In the simulation study, endotracheal intubation in difficult airway conditions performed by paramedics using McGrath video laryngoscopy was associated with shorter procedure duration, better glottis visualization, and higher efficacy of the first intubation attempt. The study showed that paramedics were able to intubate using the McGrath videolaryngoscope with higher efficiency than in the case of a standard Macintosh laryngoscope after a short training.