1　临床资料例 1 :患儿 ,女 ,2岁 ,因犬吠咳嗽、发热 1天 ,加重伴呼吸困难 2小时入院。查体 :患儿意识模糊 ,呼吸极度困难 ,面色紫组 ,脉搏细弱 ,吸气性软组织三凹征明显。诊断为小儿急性喉炎并喉梗阻Ⅳ度。急于无麻下行气管切开术。术后患儿呼吸平稳 ,紫绀渐消退 ,症状缓解 , 1 clinical data example 1: children, female, 2 years old, because of barking cough, fever 1 day, increased with difficulty breathing 2 hours admission. Physical examination: children with vague awareness, breathing extremely difficult, complexion purple group, pulse weak, inspiratory soft tissue three recess sign obvious. Diagnosis of pediatric acute laryngitis and laryngeal obstruction Ⅳ degree. Hurry without tracheotomy tracheotomy. Postoperative children with stable breathing, cyanosis subsided, symptoms,