We thank Xue et al. [1] for their interest in our study reporting findings from a universal paediatric videolaryngoscopy implementation programme. We systematically mapped the glottic view using a recognised six-stage glottic view grading [2-4] that has been prospectively evaluated specifically for glottic view grading with videolaryngoscopy and comprises the most relevant reported glottic landmarks [3]. We found that videolaryngoscopy reduced glottic view restrictions from 13% to 4% compared with direct laryngoscopy [4]. Unfortunately, Xue et al. [1] have confused the applied six-stage glottic view grading with the Cormack and Lehane classification that only has four stages and was developed for direct laryngoscopy. Our study showed that the Cormack and Lehane classification is ineffective for grading videolaryngoscopic tracheal intubation in children.

However, Xue et al. touch on a crucial point by emphasising the importance of anatomical, functional, technical, user- and patient-centred key factors when classifying videolaryngoscopic tracheal intubation in children [1]. All these aspects were systematically assessed in the PeDiAC study and used to develop a universal classification for paediatric videolaryngoscopic tracheal intubation – the PeDiAC score – that comprises eight tracheal intubation-related factors [5]. The findings of this multivariable regression model development and validation study confirm the considerations of Xue et al. [1]; ‘impaired epiglottis’; ‘enlarged arytenoids’; ‘direct epiglottis lifting’; ‘vocal cords not visible’; ‘secretions/blood’; ‘narrowed upper airway’; ‘angle dissonance’; and ‘difficult tracheal tube placement’ were the most relevant tracheal intubation-related factors (selected from a large pool of candidates) to define difficult paediatric videolaryngoscopic intubation [5].

We documented the best glottic view grades attained using necessary optimisation manoeuvres and ideal head positioning as judged by the airway operators. External laryngeal manipulation did not affect the definition of difficult videolaryngoscopic tracheal intubation in children [5]. We assume that many paediatric anaesthetists regard external laryngeal manipulation as an inherent part of laryngoscopy. Increased lifting force was seldom seen and was irrelevant for classifying difficult videolaryngoscopic tracheal intubation in children [5] (unlike in adults [3]).

The use of stylets was left to the discretion of the airway operators. As we present real-world data, and some children were never managed with stylets (e.g. nasotracheal intubations) in contrast with those always managed with stylets (e.g. rapid sequence inductions), it is impossible to draw conclusions about the impact of stylets. To our knowledge, there is currently no clear evidence in children supporting first-choice stylet-facilitated tracheal intubation with standard videolaryngoscopy blades. Furthermore, the optimal stylet shape for Macintosh videolaryngoscopy is uncertain [6].

Difficult videolaryngoscopic tracheal intubation was defined as a difficult airway alert documented by the airway operator following videolaryngoscopy; it was not derived from the VIDIAC score. It was a designated secondary study aim to externally validate the VIDIAC score in children, as reported elsewhere [5].

Notably, we report outcomes originating from a high-risk cohort. Xue et al. [1] noted a considerably low first-attempt success rate in our study (67%). Two key facts contribute to this: our study group defined first-attempt success as only one attempt at laryngoscopy and tracheal intubation; and an independent observer assessed objective study outcomes to avoid any self-reporting bias [6]. In earlier projects, we recognised notable differences between self-reported data and findings from independent study observers, likely attributed to overly positive self-assessments.

We believe it is essential for the scientific community to reach a consensus on a clear and consistent definition of ‘first-attempt success’ to enhance the comparability of studies and the synthesis of quantitative data.

我们感谢 Xue 等人 [1] 对我们的研究感兴趣，他们报告了普遍儿科视频喉镜实施计划的结果。我们使用公认的六阶段声门视图分级 [2-4] 系统地绘制了声门视图，该分级已针对视频喉镜声门视图分级进行了前瞻性评估，包括最相关的声门标志物 [3]。我们发现，与直接喉镜相比，视频喉镜将声门视野限制从 13% 降低到 4% [4]。不幸的是，Xue 等人 [1] 将应用的六阶段声门视图分级与只有四个阶段且专为直接喉镜检查而开发的 Cormack 和 Lehane 分类混淆了。我们的研究表明，Cormack 和 Lehane 分类对儿童视频喉镜气管插管的分级无效。

然而，Xue 等人通过强调在对儿童视频喉镜气管插管进行分类时以解剖学、功能、技术、用户和患者为中心的关键因素的重要性，触及了一个关键点 [1]。PeDiAC 研究系统评估了所有这些方面，并用于开发儿科视频喉镜气管插管的通用分类——PeDiAC 评分——包括 8 个气管插管相关因素 [5]。这项多变量回归模型开发和验证研究的结果证实了 Xue 等人的考虑 [1];“会厌受损”;'增大的杓状软骨';“直接会厌提升”;“声带不可见”;'分泌物/血液';“上气道狭窄”;'角度不和谐';和“困难的气管插管置入”是定义困难儿科视频喉镜插管的最相关因素（从大量候选者中选出）[5]。

我们记录了使用必要的优化操作和气道操作员判断的理想头部定位所达到的最佳声门视图等级。喉外操作不影响儿童视频喉镜气管插管的定义 [5]。我们假设许多儿科麻醉师将喉外操作视为喉镜检查的固有部分。很少见到提升力增加，与儿童困难的录像喉镜气管插管分类无关 [5] （与成人不同 [3]）。

管心针的使用由气道操作员自行决定。由于我们提供了真实世界的数据，并且一些儿童从未使用过管心针（例如鼻气管插管）进行管理，而那些儿童总是使用管心针（例如快速序列诱导）进行管理，因此无法得出关于管心针影响的结论。据我们所知，目前没有明确的证据表明儿童支持使用标准视频喉镜刀片进行首选的探针辅助气管插管。此外，Macintosh 视频喉镜检查的最佳管心针形状尚不确定 [6]。

困难视频喉镜气管插管被定义为视频喉镜检查后气道操作者记录的困难气道警报;它不是从 VIDIAC 分数得出的。这是一项指定的次要研究，旨在外部验证儿童的 VIDIAC 评分，如其他地方报道的那样 [5]。

值得注意的是，我们报告了来自高危队列的结果。Xue 等人 [1] 在我们的研究中指出，首次尝试成功率相当低 （67%）。两个关键事实促成了这一点：我们的研究小组将首次尝试成功定义为仅尝试一次喉镜检查和气管插管;独立观察者评估客观研究结局以避免任何自我报告偏倚 [6]。在早期的项目中，我们认识到自我报告的数据与独立研究观察员的发现之间存在显着差异，这可能是由于自我评估过于积极。

我们认为，科学界必须就“首次尝试成功”的明确和一致的定义达成共识，以提高研究的可比性和定量数据的综合性。