Flexible-tip bougie vs. stylet for tracheal intubation with a hyperangulated videolaryngoscope in critical care

Abstract

We read with interest the article by Taboada et al. examining the differences between flexible-tip bougie and stylet on first-pass success rate with hyperangulated videolaryngoscopy [1]. Their study describes a higher first-pass tracheal intubation success rate with a flexible-tip bougie; however, we were surprised by the low first-pass tracheal intubation success rate in the patients allocated to the stylet group, which may reflect a heterogeneity in terms of training or experience with hyperangulated videolaryngoscopy.

Driver et al. describe a similar tracheal intubation success rate in a critical care patient population where direct laryngoscopy was used in 25% of cases, only 2% were performed by consultants with a median of 60 previous tracheal intubations and only 2% came from an anaesthesia background [2]. In contrast, Ruetzler et al. showed a 98% first-pass tracheal intubation success rate with hyperangulated videolaryngoscopy and stylet in patients undergoing cardiothoracic and vascular surgery [3]. Further, Köhl et al. showed a 97% first-pass tracheal intubation success rate in patients with anticipated difficult airways [4]. While these are different patient populations, both studies described the training programme as well as the use of a preformed stylet designed for hyperangulated videolaryngoscopy. It is of concern in the study by Taboada et al. [1] that an experienced group of anaesthetists, more than a quarter of whom were consultants, achieved a similar first-pass tracheal intubation rate as that reported by Driver et al. [2].

Our local practice is to reverse load a tracheal tube on to a preformed Gliderite Rigid Stylet (Verathon Medical Inc., Bothell, WA, USA) or a stylet bent as closely as possible to the shape of the hyperangulated blade (Fig. 1). The blade is placed midline over the tongue, a full view of the entire larynx is modified to a partial view of the vocal cords (dropping the larynx posteriorly to align the primary and secondary curves), and the styleted tracheal tube is inserted in the mouth sideways to avoid obscuring the view on the screen. If the styleted tracheal tube needs to point more anteriorly to enter the glottis, the tracheal tube is elevated rather than angled in order to avoid the tip abutting the anterior tracheal wall [5]. Once inside the trachea, gradual withdrawal of the stylet and generous rotation of the tracheal tube enables advancement of the tracheal tube down the tracheal lumen, avoiding impingement on the anterior tracheal wall.

While we congratulate Taboada et al. on elucidating the high first-pass tracheal intubation success rate of flexible-tip bougies, we implore future authors of studies using a stylet with hyperangulated videolaryngoscopy to ensure they specify an appropriate technique and that their users are trained adequately in the technique so generalisable comparisons can be made.