Bronchopulmonary dysplasia involves abnormal development of lung tissue. It is characterized by inflammation and scarring in the lungs. It develops most often in premature babies, who are born with underdeveloped lungs.
Important factors in diagnosing BPD are prematurity, infection, mechanical ventilator dependence, and oxygen exposure. BPD is typically diagnosed if an infant still requires additional oxygen and continues to show signs of respiratory problems after 28 days of age (or past 36 weeks' postconceptional age). Chest X-rays may be helpful in making the diagnosis. In babies with RDS, the X-rays may show lungs that look like ground glass. In babies with BPD, the X-rays may show lungs that appear spongy.
Most BPD cases occur in premature infants, usually those who are born at 34 weeks' gestation or before and weigh less than 4.5 pounds (2,000 grams). These babies are more likely to be affected by infant respiratory distress syndrome (RDS) which occurs as a result of tissue damage to the lungs from being on a mechanical ventilator for a long time.
Mechanical ventilators do the breathing for babies whose lungs are too immature to allow them to breathe on their own and supplies oxygen to their lungs. Oxygen is delivered through a tube inserted into the baby's trachea (windpipe) and is given under pressure from the machine to properly move air into stiff, underdeveloped lungs. Sometimes, for these babies to survive, the amount of oxygen given must be higher than the oxygen concentration in the air we commonly breathe.
Although mechanical ventilation is essential to their survival, over time the pressure from the ventilation and excess oxygen intake can injure a newborn's delicate lungs, leading to RDS. Almost half of all extremely low birth weight infants will develop some form of RDS. If symptoms persist, then the condition will be considered BPD if a baby is oxygen dependent at 36 weeks' postconceptional age.
BPD also can arise from other adverse conditions that a newborn's fragile lungs have difficulty coping with, such as trauma, pneumonia, and other infections. All of these can cause the inflammation and scarring associated with BPD, even in a full-term newborn or, very rarely, in older infants and children.
Among babies who are premature and have a low birth weight, white male infants seem to be at greater risk for developing BPD, for reasons unknown to doctors. Genetics may contribute to some cases of BPD as well.
No available medical treatment can immediately cure bronchopulmonary dysplasia. Treatment is geared to support the breathing and oxygen needs of infants with BPD and to enable them to grow and thrive.
Babies first diagnosed with BPD receive intense supportive care in the hospital until they are able to breathe well enough on their own without the support of a mechanical ventilator.
Some babies also may receive jet ventilation, a continuous low-pressure ventilation that helps minimize the lung damage from ventilation that contributes to BPD.
Infants with BPD are also treated with different kinds of medications that help to support lung function. These include bronchodilators (such as albuterol) to help keep the airways open, and diuretics (such as furosemide) to reduce fluid buildup in the lungs. Severe cases of BPD might be treated with a short course of steroids.
Antibiotics are sometimes needed to fight bacterial infections because babies with BPD are more likely to develop pneumonia. Part of a baby's treatment may involve the administration of surfactant, a natural lubricant that improves breathing function. Babies with RDS who have not yet been diagnosed with BPD may have disrupted surfactant production, so administering natural or synthetic surfactant may reduce the chance that BPD develops.
The time spent in the NICU for infants with BPD can range from several weeks to a few months. Even after leaving the hospital, a baby might require continued medication, breathing treatments, or even oxygen at home.