新生儿呼吸窘迫综合征新生儿呼吸窘迫综合征 Respiratory Distress Syndrome ( RDS )

中南大学儿科学教研室陈平洋

第七章第九节

PurposePurpose

To be familiar with etiology （病因 ）and mechanism （发病机制 ）

To master clinical manifestation （临床表现 ） and differential diagnosis （鉴别诊断 ）

To master prevention and treatment

Summary

NRDS （新生儿呼吸窘迫综合征） is primarily developmental deficiency in the amount of pulmonary surfactant ( PS, 肺表面活性物质 ) , at the air-liquid interface of the lung

RDS frequently referred to as hyaline membrane disease (HMD, 肺透明膜病 )

Summary

RDS is a disease primarily of the premature infant （未成熟儿）

Pulmonary hyaline membranes （肺透明膜 ） and atelectasis （肺不张 ）are findings at autopsy （尸体解剖）

Etiology and Mechanism

PS production and /or release by type II alveolar cells （ II型肺泡细胞）

PS appears in the amniotic fluid （羊水） between 28 ～ 32 weeks

Mature levels of PS are usually present after 35 weeks

PS ↓ → surface tension （表面张力）↑ → atelectasis （肺不张） → hypoxia （低氧血症 ） and acidosis （酸中毒 → ） pa vasoconstriction （肺动脉收缩 → ） right–to-left shunting （右向左分流） → ischemic injury （缺血性损伤 ） to the vascular bed → effusion of proteinaceous material （ 蛋白样物质）→ pulmonary hyaline membrane （肺透明膜 → ） hypoxia and acidosis ↑↑

Who Is Risk baby?

The incidence is inversely proportional to gestational age （胎龄）

<28 wk: 60% ～ 80% of infants 32 ～ 34 wk: 15% ～ 30% of infants >37 wk: 5% of infants Infants of diabetic mothers （糖尿病母亲之婴儿）

Clinical Manifestations

The infant with RDS is mostly premature

Respiratory distress （呼吸窘迫 ）usually begin 2 to 6 hours after birth

dyspnea （ 呼 吸 困 难 ） , cyanosis （ 发 绀 ） , and an expiratory grunt （呼气性呻吟）

The clinical manifestation is progressive worsening （进行性加重） Uncomplicated （无并发症） cases are characterized by worsening of the disease for 2 ～ 3 d with recovery at 72 hr

胃液泡沫稳定试验

1 ml of gastric juice （胃液 ） with an equal volume of 95% ethanol （酒精 ）→ shake 15 sec → static state 15 sec

Fetal lung maturity ： （＋） RDS ： （ - ）

Radiologic Features

Ground glass （毛玻璃样） with air bronchograms （支气管充气征 )

As the disease progresses, the lung may become white-out lung (白肺 )

Treatment

一 . Specific therapy1. Surfactant replacement （表面活性

物质替代） The mammalian （哺乳动物 ）

surfactant is currently preferred PS should be given under conditions

of adequate mechanical ventilation （机械通气 ）

2.Continuous positive airway pressure (CPAP, 持续气道压力 )

CPAP may be administered by nasal prongs （鼻塞 ） , mechanical ventilation(机械通气 ）

3.Closure of the patent ductus arteriosus （ PDA ）

PDA should be closed , either with indomethacin （消炎痛 ） therapy or with surgery

 

二 . Supportive management

1. Maintain a neutral thermal temperature(中性温度 )

2. Administer adequate fluids and electrolytes （水、电解质）

Prevent fluid overload

3.  Correct acid-base disturbances

（酸碱失衡）

CPAP by nasal prongs

Prevention

1. Prevent premature labor （早产）2. Predict the risk of RDS by

testing of amniotic fluid ：lecithin/sphingomyelin ( L/S, 卵磷脂 / 鞘磷脂 ) ratio 〉 2.0 , indicates fetal lung maturity

3. Accelerate fetal lung maturation( 加快胎肺成熟）

Administration of dexamethasone （ 地 塞 米 松 ） to women 48hr before delivery

4. Administration of a first dose of PS （肺表面活性物质） into the trachea of infants immediately after birth or during the first 24hr of life

Differential diagnosis(鉴别诊断 ) 1. Meconium pneumonitis （胎粪性肺炎）

Gestational age fullterm infant （足月儿）Etiology Hypoxia （缺氧）

History

Clinical manifestations

Radiologic features

Meconium –stained amniotic fluid （胎粪性羊水）Signs appear with in minuts of birth,

barrel-shaped chest （桶状胸） , Prolonged expiration, and rales （罗音 ） may be audible.

Hyperinflation （肺气肿 ） , irregular, streaky densities with areas of atelectasis （肺不张） , Pneumothorax （气胸）

 

2. Infectious pneumoniaGestational age

Etiology

History

Clinical manifestations

Radiologic features

Each Gestational age （各胎龄）Bacteria, virus and other microbe

Infection,Prolonged rupture of membranes （早破水 ） ,URI （上呼吸道感染）May occur at any time with nasal obstruction（鼻塞） , coughing （咳嗽） ,Tachypnea（呼吸急促）

The sign is indefinite

Pneumomediastinum Pneumonia

（纵隔积气） （肺炎）