1　病例介绍患儿 ,女 ,2 0 d。因生后发绀、咳嗽、呼吸困难 5d入院。体检 :体温 35.7℃ ,呼吸 52次 /min,体重 3.5kg。无特殊面容。反应差 ,嗜睡 ,下颌样呼吸。全身皮肤粘膜紫绀 ,吸气三凹征阳性。双肺无异常。心前区无隆起 ,心尖搏动位于第 5肋间右乳头线外 1 cm,搏动不弥散 , 1 case description children, female, 20d. Due to postnatal cyanosis, cough, difficulty breathing 5d admission. Physical examination: body temperature 35.7 ℃, breathing 52 times / min, weight 3.5kg. No special face. Poor response, lethargy, jaw-like breathing. Systemic skin and mucous membrane cyanosis, inhalation three concave sign positive. No abnormal lungs. Pre-anterior zone without uplift, apical beating is located in the 5th intercostal right nipple line 1 cm, beats by dre, pulsation is not dispersed,