Symptoms and signs of respiratory distress vary and include nasal flaring; intercostal, subcostal, and suprasternal retractions; weak breathing, irregular breathing, or a combination; tachypnea and apneic spells; cyanosis, pallor, mottling, delayed capillary refill, or a combination; and hypotension. In neonates, symptoms and signs may be apparent immediately on delivery or develop minutes or hours afterward.

Etiology

Respiratory distress in neonates and infants has multiple causes (see Table 1: Respiratory Disorders in Neonates, Infants, and Young Children: Causes of Respiratory Distress in Neonates and Infants).

Table 1
PrintOpen table in new window
Causes of Respiratory Distress in Neonates and Infants Category Causes Cardiac Right-to-left shunting with normal or increased pulmonary flow: Transposition of the great vessels, total anomalous venous return, truncus arteriosus, hypoplastic left heart syndrome Right-to-left shunting with decreased pulmonary flow: Pulmonary atresia, tetralogy of Fallot, critical pulmonic stenosis, tricuspid atresia, single ventricle with pulmonic stenosis, Ebstein's anomaly, persistent fetal circulation/persistent pulmonary hypertension Respiratory Upper tract: Choanal atresia or stenosis, tracheobroncholaryngeal stenosis, compressive obstruction (eg, vascular ring), tracheoesophageal anomalies (eg, cleft, fistula) Lower tract: Respiratory distress syndrome, transient tachypnea of the newborn, meconium aspiration, pneumonia, sepsis, pneumothorax, congenital diaphragmatic hernia, pulmonary hypoplasia, cystic malformation of the lung, congenital deficiency of surfactant proteins B or C Neurologic Intracranial hemorrhage or hypertension, oversedation (infant or maternal), diaphragmatic paralysis, neuromuscular disease, seizure disorder Hematologic Methemoglobinemia, polycythemia, severe anemia Miscellaneous Hypoglycemia, blood loss, metabolic disorders (eg, acid-base disorders, hyperammonemia), hypovolemic shock

Physiology

There are several significant differences in the physiology of the respiratory system in neonates and infants compared with that of older children and adults. These differences include

• A more compliant collapsible chest wall
• More reliance on diaphragmatic excursions over intercostal muscles
• Collapsible extrathoracic airways

Also, infants' smaller airway caliber gives increased airway resistance, and absence of collateral ventilation increases tendency toward atelectasis. Yet, other principles of respiration are similar in adults and children.

Evaluation

Evaluation starts with a thorough history and physical examination.

History in the neonate focuses on maternal and prenatal history, particularly gestational age, maternal infection or bleeding, meconium staining of amniotic fluid, and oligohydramnios or polyhydramnios.

Physical examination focuses on the heart and lungs. Chest wall asymmetry or sunken abdomen suggests diaphragmatic hernia. Asymmetric breath sounds suggest pneumothorax, pneumonia, or asthma. A displaced left apical impulse, heart murmur, or both suggest a congenital heart defect. Assessment of BP and femoral pulses may identify circulatory collapse with or without congenital defects. Poor capillary refill reflects circulatory compromise.

In both neonates and infants, it is important to assess oxygenation and response to O₂ therapy by pulse oximetry or blood gases. Chest x-ray also is recommended.

Last full review/revision March 2009 by Anand D. Kantak, MD; John T. McBride, MD