Expanding clinical applications of augmented reality laryngoscopy: a need for further exploration and validation

Abstract

We write in to response to the comments provided by Orrock and Ward [1] and Inoue et al. [2] on our article [3].

In our preliminary research, we did not conduct a strict randomised controlled trial. Instead, we recruited 15 volunteers to evaluate the comfort, visual satisfaction and overall satisfaction of using different laryngoscopes for tracheal intubation. We acknowledge the difficulty of blinding operators in such studies and the limitations of using models in airway studies, particularly their lack of tissue plasticity. This can affect blade lifting and require the operator to be closer to the model for an appropriate glottic view. Currently, we are conducting a randomised controlled trial to assess the clinical usability and efficacy of the augmented reality laryngoscope.

Regarding the concerns about image bias and non-standard tracheal intubation techniques, the positions depicted in our article, although different from those preferred by Orrock and Ward, are used commonly in our clinical practice. A review of relevant recent tracheal intubation videos on the internet revealed similar techniques, suggesting that these variations may be due to individual practice habits [4, 5]. We agree that musculoskeletal strain related to laryngoscopy is a common issue in anaesthesia, and propose a multifaceted approach to mitigate this [6]. This includes standardised training; adopting the head-up (semi-Fowler's) position; using pillows/neck supports for optimal cervical flexion/extension; adjusting the operating table height; and designing novel laryngoscopes and tracheal intubation protocols using artificial intelligence [7, 8].

Inoue et al. have also rightly pointed out the potential influence of practitioner experience on the ergonomics and effectiveness of augmented reality laryngoscopes, a factor our initial study did not address. Novice practitioners tend to exhibit greater forward flexion and head movement during tracheal intubation compared to experts, regardless of the laryngoscope used. This difference is particularly evident when comparing Macintosh and videolaryngoscopes, with novices often requiring more substantial adjustments to achieve an adequate glottic view. However, experienced anaesthetists also exhibit variations in their tracheal intubation techniques due to factors including habit and vision issues. We appreciate the insights and agree that failing to account for operator experience could limit the applicability of our findings. Augmented reality technology may offer greater benefits to less experienced practitioners by providing a more intuitive and visual representation of the laryngeal anatomy. Viewing an enlarged, three-dimensional image of the larynx without adjusting posture could facilitate learning and improve technique among novice anaesthetists.

The use of videolaryngoscopes with articulable and rotatable screens is noted. However, during our clinical use of an integrated videolaryngoscope, the screen is not at eye level, requiring downward head movement for adequate visualisation. The screen's size necessitates proximity for clear viewing, highlighting the difference from augmented reality glasses that allow for eye-level operation.

Further exploration of the impact of practitioner experience on the use of augmented reality laryngoscopes is essential. Future studies should include a broader range of participants, encompassing both novice and experienced anaesthetists, to comprehensively assess the benefits and challenges of this emerging technology. This will help tailor the design and training protocols for augmented reality laryngoscopes to meet the needs of practitioners at all skill levels.

We share the concern about using industrial endoscopes instead of clinically designed devices. In our ongoing research, we are collaborating with manufacturers to develop a clinical grade augmented reality laryngoscope tailored for patient use.

Tracheal intubation practices can vary widely across regions; experience levels; clinical settings; and operational constraints. Our goal was not to dismiss the clinical value of direct or videolaryngoscopes but to introduce an innovative augmented reality laryngoscope and compare it with existing tools. We believe our augmented reality laryngoscope represents a novel concept that could revolutionise tracheal intubation practices. We are eager to collaborate with anaesthetists worldwide to create a portable, fully developed head-mounted display system for augmented reality laryngoscopy, enhancing the tracheal intubation experience and safeguarding the wellbeing of both anaesthetists and patients.