Severe respiratory distress secondary to pneumothorax or pleural effusion is due to the restrictive effects of air pressure or fluid, making it difficult for the newborn to expand the lungs for adequate ventilation.

Pneumothorax

Pneumothorax is a common cause of respiratory distress in the newborn. Air leaking from the lungs into the pleural cavity causes a pneumothorax. As air accumulates in the pleural space, it surrounds the lung. If this causes a significant restriction of lung motion, it results in respiratory distress. 

Pneumothorax can occur spontaneously, or it can be iatrogenic after the administration of PPV. Preterm babies and infants with meconium aspiration are at high risk as well. 

A significant pneumothorax restricts blood flow within the mediastinal structures and leads to oxygen desaturation and bradycardia. Pneumothorax is an emergency, and the immediate release of this trapped air is a priority. 

When a baby suddenly deteriorates or fails to improve despite high-quality resuscitative efforts, the healthcare provider must rule out the possibility of pneumothorax. The presence of a pneumothorax can often be confirmed by auscultating for breath sounds. However, the resonance of breath sounds in the infant’s small thoracic cavity can cause distortion and lead to false-negative detection of pneumothorax. 

Diminished breath sounds are a common finding on the side of the pneumothorax. Other causes of diminished breath sounds include inadequate ventilation, improper endotracheal tube positioning, pleural effusion, tracheal obstruction, congenital diaphragmatic hernia, pulmonary hypoplasia, cardiomegaly, and failure of or leaks in PPV equipment.

Transillumination of the chest is another tool to detect pneumothorax. Transillumination is performed in a dark room, using a high-intensity light source pointed at the newborn’s chest. If a pneumothorax is present, one side of the chest wall will light up more brightly than the other. The side of the chest with the brightest transillumination site is the side of the pneumothorax. For stable babies, a chest X-ray is the most accurate diagnostic modality for detecting pneumothorax.

If the pneumothorax is small, it may resolve spontaneously. A small pneumothorax does not typically cause respiratory distress but warrants continuous monitoring. A pneumothorax causing respiratory distress is treated with thoracentesis.

Pleural Effusion

Pleural effusion is the collection of fluid within the pleural space. A pleural effusion can cause respiratory distress if the fluid volume significantly restricts the lungs and mediastinal structures. Extravasation of fluid from the lungs into the pleural space can be due to edema, infection, or leakage from the lymphatic system. 

A large pleural effusion may be detected during a routine maternal ultrasound. Infants with severe fetal anemia, twin-to-twin transfusion, cardiac arrhythmia, congenital heart disease, or a genetic syndrome are at risk for pleural effusion. A newborn with respiratory distress and generalized edema may have fetal hydrops and is at high risk for pleural effusion. Babies with hydrops are also prone to have ascites and pericardial effusion. 

Breath sounds on the side of the pleural effusion are decreased, but the definitive diagnosis is a chest X-ray.

Small pleural effusions do not usually require thoracentesis. If the obstetrician recognizes pleural effusion before birth, the baby must be born in a facility with equipment and experience in performing thoracentesis of the newborn.