常规应用于成人的气管内插管方法对儿童可能发生困难,既使是个别的。选择适当大小的气管导管是病儿插管成功的关键。本研究是属前瞻性评估,在选择性气管内插管下直接比较,以年龄基数公式和以小儿第Ⅴ指的宽度来选择导管大小的精确性。研究者事先不了解麻醉医师认为合适的导管管径,而在插管后监听导管周围漏气声,如果漏气介于5～40cmH_2O间认为是可接受的。术后检查每一病儿第Ⅴ指的宽度、直经和第Ⅴ指甲的宽度。 Tracheal intubation, which is routinely used in adults, can be difficult, if not individual, for children. Choosing the appropriate size of the tracheal tube is the key to the success of the sick child intubation. This study is a prospective assessment comparing direct selec- tive endotracheal tubes to the accuracy of catheter size using the age-based formula and the width of pediatric V-notch. The investigators did not know in advance what the anesthesiologist thought was appropriate for the diameter of the catheter, but after the intubation, the sound of the leak around the catheter was perceived as acceptable if the leak was between 5 and 40 cm H2O. Postoperative examination of each sick child, the first Ⅴ refers to the width, straight and Ⅴ nail width.