We read with interest the study by Ding et al. [1]. The application of augmented reality technology to medical procedures is a promising advancement, and we concur with the authors' perspective on its potential to reduce occupational health risks in medical professions, while also enhancing procedural safety and accuracy. We have a concern about the study's data on Macintosh and videolaryngoscopes. It is unclear if the results are generalisable without accounting for the practitioners' proficiency levels.

We conducted a series of studies investigating the postural changes and gaze distribution during tracheal intubation in a simulation setting using motion capture and eye-tracking, focusing on comparisons between novice and experienced practitioners [2, 3]. The vertical head movement during tracheal intubation using the Macintosh laryngoscope differed significantly between novices and experts. Novices exhibited downward movement of 23.5 cm from mouth opening to tracheal tube insertion, whereas the experts showed downward movement of only 3.5 cm [2]. Furthermore, when using the McGrath® videolaryngoscope (Medtronic, Watford, UK), the novices exhibited a downward movement of the head of 10.7 cm, whereas the experts hardly lowered their heads [3].

Our findings are consistent with those of Ding et al. [1] regarding how the degree of forward flexion varies with the type of laryngoscope used. However, our study further shows that posture during tracheal intubation differs markedly between novices and experts. Specifically, novices exhibit a greater forward flexion, whereas experts maintain a relatively straight posture with minimal head displacement, although the precise angle of upper body flexion was not quantified in our study. Similar findings have been reported in studies using different evaluation methods in simulation settings. Grundgeiger et al. found that novices exhibited significantly more flexion of the trunk and neck compared with experts [4]. Although Ding et al. cited this, they did not mention the differences between novices and experts. In addition, Matthews et al. measured the distance from the patient's nose to the manikin's chin and reported that it was significantly shorter in the novice than the expert group, indicating that novices tended to crouch, while experts maintained a more upright posture during tracheal intubation [5].

In conclusion, it may not be accurate to claim that all users adopt a forward-leaning posture when using the Macintosh or videolaryngoscope. The failure to account for operator experience may influence the conclusion of such studies significantly, as the degree of forward flexion during tracheal intubation can vary considerably between novices and experts. This possibility of misinterpretation could limit the applicability of augmented reality technology and overestimate its benefit for experienced practitioners. We are also interested in understanding whether there are differences in posture between novices and experts when using this technology for tracheal intubation. A comprehensive understanding of these distinctions is crucial for the effective optimisation of augmented reality technology in clinical practice.

我们饶有兴趣地阅读了 Ding 等人 [1] 的研究。增强现实技术在医疗程序中的应用是一项有前途的进步，我们同意作者的观点，即它有可能降低医疗行业的职业健康风险，同时提高程序安全性和准确性。我们对 Macintosh 和电子喉镜上的研究数据表示担忧。目前尚不清楚如果不考虑从业者的熟练程度，结果是否具有普遍性。

我们进行了一系列研究，使用动作捕捉和眼动追踪在模拟环境中调查气管插管过程中的姿势变化和注视分布，重点是新手和有经验的从业者之间的比较 [2， 3]。使用 Macintosh 喉镜进行气管插管期间头部垂直运动在新手和专家之间差异显著。新手从张口到插入气管插管时向下移动 23.5 cm，而专家显示仅向下移动 3.5 cm [2]。此外，当使用 McGrath® 电子喉镜（Medtronic，Watford，UK）时，新手的头部向下运动了 10.7 cm，而专家几乎没有低下头 [3]。

我们的研究结果与 Ding 等人 [1] 关于前屈程度如何随所用喉镜类型而变化的研究结果一致。然而，我们的研究进一步表明，新手和专家在气管插管过程中的姿势存在显着差异。具体来说，新手表现出更大的前屈，而专家保持相对笔直的姿势，头部位移最小，尽管在我们的研究中没有量化上半身屈曲的精确角度。在模拟环境中使用不同评估方法的研究中也报告了类似的发现。Grundgeiger 等人发现，与专家相比，新手的躯干和颈部弯曲明显更多 [4]。虽然 Ding 等人引用了这一点，但他们并没有提到新手和专家之间的差异。此外，Matthews 等人测量了患者鼻子到人体模型下巴的距离，并报告说，新手的距离明显短于专家组，表明新手倾向于蹲下，而专家在气管插管时保持更直立的姿势 [5]。

总之，声称所有用户在使用 Macintosh 或视频喉镜时都采取前倾姿势可能不准确。未能考虑操作者的经验可能会显著影响此类研究的结论，因为气管插管期间前屈的程度在新手和专家之间可能有很大差异。这种误解的可能性可能会限制增强现实技术的适用性，并高估其对经验丰富的从业者的好处。我们还有兴趣了解在使用这项技术进行气管插管时，新手和专家之间的姿势是否存在差异。全面了解这些区别对于在临床实践中有效优化增强现实技术至关重要。