Objective

To determine the accuracy of the recently proposed landmark-method ‘nostril-to-tragus minus 10 mm’ and compare with ERC-recommended distances for nasopharyngeal airway length sizing in children.

Method

We conducted a prospective observational study in sedated children < 12 years. Nasopharyngeal airways were inserted following ‘nostril-to-tragus minus 10 mm’. Primary outcome was the rate of nasopharyngeal airway tips between soft palate and epiglottis on magnetic resonance imaging (MRI) indicated for medical reasons. An optimal placement was defined when the tip lied within 25–75% of the total soft palate-to-epiglottis distance. Between 0–100% of this distance, placement was still considered acceptably, below 0% too proximal or above 100% too distal. Secondary outcomes were the rate of adverse events, the qualitative positions of airway tips, and the comparison of ́nostril-to-tragus minus 10 mḿ with the ERC-recommended distances ‘nostril-to-angle of the mandible’ and ‘nostril-to-tragus’ with objective MRI measurements.

Results

We analysed 92 patients with a mean age of 4.3 years. Nasopharyngeal airways were optimally placed in 37.0% (8.7% too proximal-77.2% acceptable-14.1% too distal). Three qualitative malpositions, but no airway-associated adverse event occurred. Objective measurements on MRI revealed the probability of 40.2% optimally placed nasopharyngeal airways (5.4%–67.4%–27.2%) for ‘nostril-to-tragus minus 10 mm’, 38.0% (17.4%–58.7%–23.9%) for ‘nostril-to-mandible’ and 13.0% (0%–28.3%–71.7%) for ‘nostril-to-tragus’, respectively.

Conclusion

No landmark-method predicted nasopharyngeal airway position reliably. ‘Nostril-to-tragus minus 10 mm’ seems the least inaccurate one and could be a valuable approximation until another estimation-formula proves more accurate. During insertion, careful clinical evaluation of airway patency is crucial.

Registered clinical trial

German Clinical Trials Register; DRKS00021007.

中文翻译：

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使用估计公式预测儿童鼻咽气道插入深度：查看磁共振图像 – 一项前瞻性观察研究 (WEND:LI-Study)

客观的

确定最近提出的标志性方法“鼻孔到耳屏减去 10 毫米”的准确性，并与 ERC 推荐的儿童鼻咽气道长度测量距离进行比较。

方法

我们对 <12 岁的镇静儿童进行了一项前瞻性观察研究。在“鼻孔到耳屏减 10 毫米”后插入鼻咽气道。主要结果是在磁共振成像 (MRI) 上出于医学原因指示的软腭和会厌之间的鼻咽气道尖端的比率。当尖端位于软腭到会厌总距离的 25-75% 内时，定义了最佳位置。在这个距离的 0-100% 之间，放置仍然被认为是可以接受的，低于 0% 太近或高于 100% 太远。次要结果是不良事件发生率、气道尖端的定性位置，以及鼻孔到耳屏 - 10 mḿ 与 ERC 推荐的“鼻孔到下颌角”和“鼻孔到-”距离的比较耳屏的客观 MRI 测量。

结果

我们分析了 92 名平均年龄为 4.3 岁的患者。鼻咽气道的最佳位置为 37.0%（8.7% 太近端 - 77.2% 可接受 - 14.1% 太远端）。三个定性错位，但没有发生与气道相关的不良事件。MRI 的客观测量显示，对于“鼻孔到耳屏 - 10 mm”，最佳放置鼻咽气道的概率为 40.2%（5.4%–67.4%–27.2%），对于“”为 38.0%（17.4%–58.7%–23.9%）鼻孔到下颌骨”和“鼻孔到耳屏”分别为 13.0% (0%–28.3%–71.7%)。

结论

没有标志性方法可靠地预测鼻咽气道位置。“鼻孔到耳屏减去 10 毫米”似乎是最不准确的，并且在另一个估计公式证明更准确之前可能是一个有价值的近似值。在插入过程中，对气道通畅性进行仔细的临床评估至关重要。

注册临床试验

德国临床试验注册；DRKS00021007。