Comparison of Macintosh and Intubrite laryngoscopes for intubation performed by novice physicians in a difficult airway scenario.

INTRODUCTION: In the difficult airway, the intubation skills are critically important. In selected cases, particularly in airway edema, laryngeal or tongue edema, endotracheal intubation can turn out very difficult, and repeated attempts may even worsen the airway edema, causing trauma and bleeding, and finally leading to complete airway obstruction and inability to ventilate the patient.

AIM OF THE STUDY: The aim of the study was to compare the efficacy of endotracheal intubation performed by novice physicians using a standard Macintosh laryngoscope and an Intubrite videolaryngoscope.

MATERIAL AND METHODS: The study was designed as a prospective, randomized, crossover, simulation study and continues our research assessing the effectiveness of selected endotracheal intubation techniques in prehospital settings. All participants were experienced with the Macintosh direct laryngoscope but remained novice to videolaryngoscopy. Instructions on the correct use of the Macintosh and Intubrite laryngoscopes were given before the procedure, and all the 30 novice physicians were allowed to practice at least 10 times before the study on manikin with normal airways. We employed an airway manikin (Trucorp Airsim Bronchi; Trucorp Ltd., Belfast, Northern Ireland) to simulate difficult airway, with was obtained by inflating the tongue with 50mL of air. The participants were asked to perform tracheal intubation using an endotracheal tube with 7.5mm of internal diameter (Portex; Smiths Medical, Hythe, UK) through the vocal cords, applying either a conventional Macintosh laryngoscope with a size 3 blade (MAC; Mercury Medical, Clearwater, FL, USA) or the Intubrite videolaryngoscope, also with a Macintosh No. 3 blade (INT; Intubrite Llc, Vista, CA, USA). In both intubation techniques, a guide stylet (Rusch Inc., Duluth, GA, USA) was introduced into the endotracheal tube in order to obtain a C-shape curve to facilitate tracheal intubation. Each participating physician was randomly assigned to three attempts of tracheal intubation with each device.

RESULTS: The effectiveness of the first intubation attempt using MAC and INT was 63.6% and 53.4%, respectively (p=0.023), and the total percentage of intubation was 100% for both methods. The median time to intubation was 29.5 (interquartile range [IQR], 27-35.5) s with MAC, and 229 (IQR, 25.5-37) s with INT. The total of 24 physicians out of all study participants would choose MAC as a device to intubate with in real terms, while only 6 physicians would choose INT.

CONCLUSIONS: During the simulation study, the novice physicians were able to perform endotracheal intubation at the same time using both the Macintosh and Intubrite videolaryngoscope. However, the efficacy of the first intubation attempt was higher for MAC. Further studies are needed to confirm the results.