Neonatal Respiratory Disease
Respiratory disease is a common cause of neonatal morbidity.
Transient Tachypnea of the Newborn
The etiology of this condition is thought to be delayed resorption of fetal lung fluid. This condition is more common in term infants, especially those delivered by cesarean section. The symptoms consist of tachypnea, grunting, and nasal flaring. The infant might display cyanosis. Most infants recover within 12 to 24 hours, though the symptoms may last as long as three days. Oxygen therapy is usually required for a few hours. Radiographic examination reveals central perihilar streaking and fluid in the fissures.
Meconium Aspiration Syndrome
Meconium staining is seen in about 10% of all pregnancies and almost half of post-date pregnancies and may result from intrauterine fetal distress. The aspiration of meconium- stained amniotic fluid results in severe respiratory distress. The thick material produces a ball-valve effect with areas of over- expansion and atelectasis. Pneumothorax is a frequent complication in the over-expanded areas of the lung. Oxygenation and ventilation are compromised, and persistent pulmonary hypertension might result.
Respiratory Distress Syndrome (RDS)
RDS results from the inability of the premature infant to synthesize pulmonary surfactant (surface-active lecithin). Surfactant is essential to reduce alveolar surface tension and keep the alveoli open during expiration. The hallmark of RDS is diffuse atelectasis.
RDS is uncommon in the term infant. The more premature the infant, the more likely the development of RDS. In addition to prematurity, the risk for RDS is increased by conditions that delay lung maturity such as maternal diabetes, male sex, and Caucasian race. Conversely, lung maturity can be hastened by the stress of intrauterine growth retardation and also by administration of antenatal glucocorticoids to the mother.
The infant with RDS displays tachypnea, retractions, nasal flaring, grunting, and cyanosis within a few hours of birth. The chest radiograph demonstrates a reticulo-granular "ground-glass" appearance with air bronchograms.
Administration of oxygen, artificial surfactant and respiratory support are the keystones of management.
