Comparison of the Facilitation of Intubation among Three Tracheal Tube Introducers in Simulated Patients with a Difficult Airway

Abstract

Background: This randomized study was performed to compare the efficacy of facilitation of intubation through a gum elastic bougie (GEB), Teflon solid tube, or conventional stylet in simulated patients with a difficult airway. Methods: After anesthesia induction with thiopental 5 mg/kg and vecuronium 0.1 mg/kg iv and maintenance with -enflurane, a laryngoscopic assessment, as described by Cormack and Lehane, was performed in 45 patients of ASA physical status 1 or 2. Each group (n = 15) was randomly assigned by a minimisation method to ensure that an equal number of patients with the same laryngoscopic views were allocated to each group. A grade 3 view of the glottis was simulated by slightly withdrawing the Macintosh blades from the vallacula, so that direct view of the glottis was completely obscured. The time to successful intubation and the number of attempts were measured and compared, and the incidence of noticeable 'clicking' of intubation into the trachea was recorded and used for comparison. Results: The intubation time was the same in the stylet and the Teflon solid tube groups, which was followed by the GEB group. The number of advances of the endotracheal tube over the guide or the tube-guide combination was less in the GEB and the Teflon solid tube group, which was followed by the malleable stylet group. Resistance to advancing a tube over the anterior wall of the trachea was the most severe and prevalent in the stylet group. The 'clicking' sense, which could not be felt while advancing the stylet, was noticed in the about 80% of the Teflon solid tube group, but only 60% of the GEB group. Conclusions: Of the three intubation guides, the Teflon solid tube appears to be the best in that even a novice can easily handle it, and it is cheaper and more durable than the GEB. Though we can rapidly accomplish intubation with a stylet, it may not be recommended for a grade 3 airway.