Abstract: Objective　To determine the accuracy of the standard techniques for estimating the endotracheal tube insertion depth in children，including the formula from PALS guiding，the clinical evaluation method with auscultation of bilateral breathing and observation of chest fluctuation，then to forma more feasible predictive formula for clinical practice. Methods　we retrospectively collected a total of 177 children with oral endotracheal intubation who were treated from January 2018 to July 2019 in the Pediatric Intensive Care Unit of Shengjing Hospital of China Medical University. Theage，gender，and weight of the child for the initial intubation after admission，the intubation depth calculated according to the PALS guideline formula，the actual insertion depth after clinical evaluation，and the distance from the tip of ETT to the lower edge of the second thoracic vertebra and to the carina were documented. The above data were statistically analyzed. Results　About 74.01% tubes that adhered to PALS guideline depth were malpositioned. After clinical evaluation，the ETT malposition rate decreased from 74.0% to 55.9%，which meant that clinical evaluation was of significance to ETT adjustment. A new formula was proposed：in children≤2 year old，11 cm for infants aged 1-5 months，12 cm for infants aged 6-11 months and 13 cm for infants aged 12-23 months were used as the ETT referenced depth children over 2 years：intubation depth（cm）＝age（years）×0.7+12. Conclusion　The rate of malpositioned endotrache tubes adhered to PALS guidelines is high. The rate of proper positioned endotracheal tubes can be improved after the clinical evaluation of auscultation and chest fluctuation. The PALS guideline underestimates the best depth of ETT for children equal to and older than 2 years. The new formula has yet to be verified. 

Key words: endotracheal , intubation, auscultation, malpositioned endotracheal tube, PALS, PICU

摘要： 目的　探讨多种儿童经口气管插管深度标准技术的准确性，包括儿科高级生命支持（PALS）指南公式预测法以及听诊双肺呼吸音、观察胸廓起伏的临床评估法，并设计更准确的预测公式指导临床。方法　回顾性分析2018年1月至2019年7月中国医科大学附属盛京医院小儿重症监护病房收治的经口气管插管的177例患儿。记录入院后初次插管时患儿的年龄、性别、体重、依据PALS指南公式计算的插管深度、临床评估后的实际插入深度以及胸片显示气管导管（endotracheal tube，ETT）尖端距离第二胸椎下缘和隆突的距离，并对上述数据进行统计分析。结果　依据PALS指南计算所得气管插管深度的错位率（过深或过浅）为74.01%，结合临床评估后，ETT错位率由74.0%下降至55.9%，临床评估对ETT的调整有实际意义。推测新公式：＜2岁患儿，采用1～5月龄：11 cm，6～11月龄：12 cm，12～23月龄：13 cm作为参考插管深度。 ≥2岁患儿：插管深度（cm）＝年龄（岁）×0.7+12。结论　依据PALS指南计算的气管插管深度错位率较高，通过听诊双肺呼吸音、观察胸廓起伏等临床评估后可提高ETT位置的合适率。PALS指南低估了2岁以上儿童ETT的最佳插入深度。新的公式有待验证。

关键词: 气管内插管, 听诊, 气管插管错位, 儿科高级生命支持, 儿科重症监护