Pneumothorax in neonates.
Review risk factors and at-risk populations; symptoms and diagnosis; clinical management options and outcomes.
A pneumothorax occurs when air enters the pleural space, typically becoming trapped there. In neonates it is most often secondary to a pulmonary process such as respiratory distress syndrome (RDS) or transient tachypnea of the newborn (TTN) and typically occurs after the application of positive airway pressure. Pneumothorax can also occur spontaneously in newborn infants; this is thought to be related to unequal distribution of air in the partially liquid-filled lungs as they are expanding and the infant is crying and generating its own positive expiratory pressure.
The clinical spectrum of neonatal pneumothorax includes the term infant exhibiting only mild tachypnea who has a pneumothorax seen on chest x-ray (CXR), to the critically ill infant with a tension pneumothorax resulting in cardiac arrest, and a broad spectrum of illness in between. Pneumomediastinum may also occur, and in rare cases is large enough to result in cardiac compression.
Existing population data are quite old, but the incidence of pneumothorax may be as high as 1–2% in newborn infants, though the vast majority are asymptomatic. Symptomatic pneumothorax is much more rare on a population basis, estimated at 0.1% though much more common in patients requiring treatment in the neonatal intensive care unit (NICU) (1.6–4.4%), especially in the most premature infants (<28 wk, 4–14%). Pneumothorax most typically occurs in the first 72 hours after birth, though later ones occur, especially in infants with severe lung disease. Once a common NICU event, pneumothoraces are much less frequent with current neonatal respiratory care including prenatal steroids, volume-targeted ventilation, and surfactant administration.
As with the majority of neonatal conditions, prematurity is the most important risk factor for pneumothorax (see Table 24.1). Smaller, sicker infants, particularly those requiring significant mechanical ventilation and high fraction of inspired oxygen, are at the greatest risk. Randomized trial data have shown this risk is lower when volume-targeted ventilation and early surfactant administration are used. However, early use of continuous positive airway pressure (CPAP) may obviate the need for surfactant in patients that can be appropriately supported without intubation.
TABLE 24.1.Risk Factors for Pneumothorax |Favorite Table|Download (.pdf) TABLE 24.1. Risk Factors for Pneumothorax
Lung disease (RDS, TTN, MAS)
Congenital lung malformation (CDH, CPAM)
Pulmonary interstitial emphysema
Positive pressure ventilation
High oxygen requirement
Late preterm and term infants are also at risk, especially those receiving positive pressure ventilation or CPAP either during delivery resuscitation or NICU care. Pneumothorax has become more common in this population as use of CPAP has risen.
Small pneumothoraces, especially in larger, fairly well infants, have an excellent prognosis and minimal if any mortality ...