Newborns may require ventilatory support after birth; hence, confirmation of correct tracheal tube placement is vital. The most suitable method to determine intubation success and monitoring of carbon dioxide is a matter of contention, specifically regarding the use of capnography in the newborn population. In 2018, a UK survey on airway management in neonatal intensive care reported that only 18% of units always used capnography during neonatal tracheal intubations. The authors made recommendations for waveform capnography to be available and more widely implemented in order to improve safety [1]. Such recommendations, however, were extrapolated from studies in adult intensive care. The results of that survey [1] were thus met with scepticism from members of the British Association of Perinatal Medicine (BAPM), which highlighted differences in physiological characteristics of newborn infants compared with adults. Furthermore, BAPM emphasised alternative techniques in determining intubation success in neonates, such as qualitative colorimetric devices, flow sensors and clinical judgement [2]. The development of devices more suitable for use in newborns has subsequently provided clinicians with the means to continuously and non-invasively monitor carbon dioxide during resuscitation and mechanical ventilation. Novel capnographs are lightweight and have a small dead space, and are thus ideal for use in the newborn population. Indeed end-tidal carbon dioxide (ETCO₂) values from small dead space sidestream capnographs have been shown to accurately reflect alveolar carbon dioxide levels in a cohort of healthy infants [3]. Capnography could also be utilised to alert clinicians to changing pulmonary pathology, with greater divergence of the end-tidal, compared with the arterial, carbon dioxide in those with more severe disease [4]. We therefore aimed to describe current clinical practice in UK neonatal units with respect to non-invasive carbon dioxide monitoring, specifically the use of capnography.

All level two and level three neonatal ICUs (151 units) within the UK were identified from the BAPM Neonatal Network. The survey took place between January and May 2021 using a structured online questionnaire. Units that did not complete the survey online were followed-up with a maximum of three telephone calls by a member of the research team, with responses sought from senior clinical staff (as a minimum a registrar or band 7 nurse).

A total of 126 (83.4%) units provided a complete response, 72/80 (90%) were level two and 54/71 (76.1%) were level three units. A total of 104 (82.5%) units reported monitoring carbon dioxide during all intubations. Seventy-nine (62.7%) units utilised colorimetric devices to confirm tracheal tube placement. Thirty-five (27.8%) reported use of continuous capnography monitoring, of which 10 (7.9%) also used qualitative colorimetry. Videolaryngoscopy was used to confirm successful intubation in 26 (20.6%) units. Furthermore, 23 (18.3%) confirmed tracheal tube position using clinical interpretation and chest radiography. Regarding the utility of capnography on the neonatal unit, 43 (34.1%) confirmed it formed part of routine clinical care. Specific criteria and other clinical settings for capnography use are shown in Table 1. Regarding capnography interpretation during day-to-day practice in neonatal intensive care, 14 (32.6%) units utilised only the ETCO₂ value, six (13.9%) evaluated the carbon dioxide waveform trace and 21 (49%) reported evaluating both the ETCO₂ value and the waveform in combination. Thirty-nine (30.9%) confirmed that capnography was part of their difficult airway trolley.

We found that exhaled carbon dioxide monitoring during tracheal intubation was undertaken by over 80% of neonatal units in the UK, with the majority utilising qualitative methods. Previous concern was expressed over the lack of routine monitoring of exhaled carbon dioxide during neonatal intubation [1]; however, the 2018 survey considered only capnography to be an appropriate monitoring tool. Our results demonstrate that neonatal intensivists do now routinely monitor carbon dioxide during tracheal intubation, utilising either qualitative or quantitative methods. Indeed, one colorimetric ETCO₂ device was shown to be 91% sensitive and 100% specific in confirming tracheal tube placement during neonatal resuscitation [5]. Quantitative waveform analysis during newborn resuscitation has, however, been shown to detect ETCO₂ more rapidly than qualitative methods [6].

In conclusion, exhaled carbon dioxide during tracheal intubation is now monitored in the majority of neonatal units, but this is usually undertaken by qualitative methods despite increasing evidence that the new capnography devices are useable and accurate in the neonatal population.

新生儿出生后可能需要通气支持；因此，确认正确的气管导管放置至关重要。确定插管成功和监测二氧化碳的最合适方法是一个有争议的问题，特别是关于在新生儿人群中使用二氧化碳图。2018 年，英国一项关于新生儿重症监护气道管理的调查报告称，只有 18% 的单位在新生儿气管插管期间始终使用二氧化碳图。作者提出了关于波形二氧化碳图的建议，并更广泛地实施以提高安全性 [ 1 ]。然而，这些建议是从成人重症监护研究中推断出来的。该调查的结果 [ 1] 因此遭到了英国围产期医学协会 (BAPM) 成员的怀疑，该协会强调了新生儿与成人相比生理特征的差异。此外，BAPM 强调了确定新生儿插管成功的替代技术，例如定性比色装置、流量传感器和临床判断 [ 2 ]。更适合新生儿使用的设备的开发随后为临床医生提供了在复苏和机械通气过程中连续无创监测二氧化碳的方法。新型二氧化碳分析仪重量轻，死腔小，因此非常适合新生儿使用。事实上呼气末二氧化碳 (ETCO ₂) 来自小死腔侧流二氧化碳图的值已被证明可以准确反映一组健康婴儿的肺泡二氧化碳水平 [ 3 ]。二氧化碳图还可用于提醒临床医生注意肺部病理变化，与动脉二氧化碳相比，更严重疾病患者的呼气末差异更大 [ 4 ]。因此，我们旨在描述英国新生儿病房在无创二氧化碳监测方面的当前临床实践，特别是二氧化碳图的使用。

英国所有二级和三级新生儿重症监护病房（151 个单位）均来自 BAPM 新生儿网络。该调查是在 2021 年 1 月至 5 月之间使用结构化在线问卷进行的。未完成在线调查的单位由研究团队成员最多拨打三个电话进行跟进，并寻求高级临床工作人员（至少是注册员或第 7 级护士）的答复。

共有 126 (83.4%) 个单位提供了完全响应，72/80 (90%) 为二级，54/71 (76.1%) 为三级单位。共有 104 (82.5%) 个单位报告在所有插管期间监测二氧化碳。七十九个 (62.7%) 单位使用比色装置来确认气管插管的位置。35 个 (27.8%) 报告使用了连续二氧化碳图监测，其中 10 个 (7.9%) 还使用了定性比色法。26 个 (20.6%) 单位使用视频喉镜确认成功插管。此外，23 名 (18.3%) 使用临床解释和胸片确认了气管插管位置。关于二氧化碳图在新生儿病房中的应用，43 (34.1%) 确认它是常规临床护理的一部分。二氧化碳图使用的具体标准和其他临床设置见表 1。_{在 2 个}值中，有 6 个 (13.9%) 评估了二氧化碳波形轨迹，21 个 (49%) 报告了评估 ETCO ₂值和波形的组合。三十九名 (30.9%) 证实二氧化碳图是他们困难气道手推车的一部分。

我们发现英国超过 80% 的新生儿病房在气管插管期间进行呼出二氧化碳监测，其中大多数使用定性方法。先前有人担心新生儿插管期间缺乏对呼出二氧化碳的常规监测 [ 1 ]；然而，2018 年的调查认为只有二氧化碳图是一种合适的监测工具。我们的结果表明，新生儿重症监护医师现在确实在气管插管期间使用定性或定量方法定期监测二氧化碳。事实上，一种比色 ETCO ₂设备在新生儿复苏期间确认气管插管放置方面的敏感性为 91%，特异性为 100% [ 5]]。然而，新生儿复苏期间的定量波形分析已显示出比定性方法更快地检测 ETCO ₂ [ 6 ]。

总之，现在大多数新生儿病房都在监测气管插管期间呼出的二氧化碳，尽管越来越多的证据表明新的二氧化碳图设备在新生儿人群中可用且准确，但通常通过定性方法进行监测。