In reply: Parallel intubation technique with the Vie Scope^® laryngoscope

To the Editor,

We thank Dr. Henlin et al.¹ for their interest in our work² and for sharing their interesting insights into the “parallel intubation technique.” We are pleased that the authors’ experience is consistent with our previously published study results^2,3 suggesting that glottis visualization with the Vie Scope^® (Adroit Surgical LLC, Oklahoma City, OK, USA) is superior to direct laryngoscopy and noninferior to Macintosh videolaryngoscopy, despite increased time-to-intubation.^2,3 In our opinion, the good visualization achieved with the Vie Scope is primarily due to direct epiglottis lifting, being a key element of straight-blade techniques and also significantly improving the glottis exposure in difficult Macintosh videolaryngoscopy.⁴

Nevertheless, some potential disadvantages of the Vie Scope must be considered:

1. The Vie Scope is designed to be used in a two-step bougie-assisted approach that prolongs time-to-intubation compared with a direct approach.^2,3

2. The tracheal tube is railroaded over the bougie without visualization of the laryngeal inlet; therefore, tube advancement cannot be visualized and tube impingement on the anterior commissure or arytenoids cannot be visually confirmed.³

3. Correct bougie placement may not be verified through the Vie Scope in situations with significantly restricted glottis view through the channel (i.e., grade 2C or worse);^4,5 in our previous study, we observed four unintended esophageal intubations in patients with expected difficult airways² probably due to bougie misplacement.

The “parallel intubation technique” suggested by Henlin et al. is very promising for avoiding “blind insertion” of the tracheal tube over the bougie and could furthermore identify a bougie misplacement before the tracheal tube is advanced. Nevertheless, this method retains a two-step approach with an inherently longer time-to-intubation. It must be considered that this technique changes the alignment between bougie and tracheal inlet; therefore, the straight bougie supplied by the manufacturer might not be suitable and a J-shaped bougie may be more appropriate. Nevertheless, this technique is not outlined by the manufacturer and no data are available so far. In our opinion, a study is required to investigate the feasibility, safety, and efficiency of this novel approach.

Thus, there are currently four described options for using the Vie Scope: 1) the median approach, 2) the paraglossal approach, 3) Vie Scope-guided tube placement (after bougie placement and reinsertion of the Vie Scope), and 4) the parallel approach, suggested by Henlin et al. In our opinion, all these approaches should be further investigated to enable a more context-dependent and personalized use of the Vie Scope tailored to the individual patient and specific clinical situation.