Bronchopulmonary Dysplasia - Specialists and Information

Bronchopulmonary dysplasia (BPD) is a chronic lung disease that occurs in premature infants. 

Premature infants are babies born before the end of the 37th week of gestation. Births before the 32nd week of gestation are referred to as “very preterm,” and those before the 28th week as “extremely preterm.” 

Bronchi are the branches of the trachea that lead into the lung tissue and continue to branch out there. Each lung lobe has a main bronchus with many secondary branches. “Pulmo” is the medical term for lung. BPD therefore refers to damage to the trachea and lung tissue. It most commonly affects premature infants, for several reasons:

1. The development of the lungs and trachea is very complex and is usually not complete until toward the end of pregnancy. In most cases, this process is not yet fully complete in premature infants, which is why mechanical ventilation is often necessary
2. Mechanical ventilation itself is a risk factor for the development of BPD

The typical signs of the disease are:

• increased respiratory rate
• cough 
• wheezing
• Production of large amounts of bronchial secretions
• bluish discoloration of the skin
• Difficulty eating and vomiting
• Developmental delays in infants

Infants affected by this condition typically breathe too rapidly and can consequently develop shortness of breath easily. The resulting low oxygen saturation in the blood causes a bluish discoloration of the skin.

Other premature infants have difficulty expelling air from their lungs, causing exhalation to slow down. As a result of this delay, air often remains in the lungs, leading to overdistension of the organ.

Furthermore, increased respiratory activity can lead to heart rate irregularities and overburden the pumping capacity of the right ventricle.

Bronchopulmonary dysplasia is a lung disease in newborns that can result from the use of a ventilator @ Tobilander /AdobeStock

Bronchopulmonary dysplasia (BPD) is primarily caused by premature birth with a very low birth weight. Babies born before the 32nd week of pregnancy and weighing less than 1,500 grams are considered particularly at risk. In these very small premature infants, the lungs are often not yet fully developed. As a result, the immature lungs are unable to produce surfactant, which is essential for breathing.

However, infants need this naturally occurring substance to breathe on their own. Surfactant is not sufficiently available to babies until the 35th week of gestation (or later). It is a fluid that lines the inside of the lungs (the alveoli). Its function is to reduce the surface tension of the alveoli and keep the airways open.

Think of it this way: when breathing in, negative pressure is created, causing the alveoli to collapse. Surfactant prevents the alveoli from collapsing from the inside, allowing them to continue participating in gas exchange. This is how infants (and, incidentally, adults as well) are able to breathe normally. Premature infants do not yet have sufficient amounts of surfactant and therefore often require mechanical ventilation.

Mechanical ventilation is one of the most important risk factors for damage to the alveoli and for the development or worsening of BPD. This is also evident in the fact that, according to current definitions and recommendations, the need for mechanical ventilation with oxygen administration within the first 28 days after birth is a key characteristic of BPD. Oxygen is administered at very high ventilatory pressures and high oxygen concentrations over an extended period of time.

On the one hand, this can damage lung tissue; on the other hand, it increases the risk of infections, particularly pneumonia. Another complication is the accumulation of fluid in the lung tissue, which can cause what is known as pulmonary edema. Mechanical ventilation should be avoided whenever possible. However, in preterm infants, it is generally essential for survival and life-saving; thus, it is not the cause but rather a consequence of lung immaturity.

To diagnose bronchopulmonary dysplasia (BPD), it is first important to measure the oxygen saturation in the infant’s blood. The lower this is, the more severe the lung disease. It is now also possible to confirm or rule out a suspected diagnosis of BPD by measuring specific laboratory parameters and proteins. Research in this field is proceeding at full speed, and further findings and opportunities for early diagnosis are expected. In many cases, these blood tests are still experimental and therefore not widely used in routine clinical practice. 

In addition, an X-ray or CT scan is performed to assess the extent of lung damage. These images reveal the extent of lung damage when the alveoli are overinflated and lung tissue is damaged. 

If the premature infant’s heart function is impaired, an ultrasound examination of the heart is also necessary. This can also provide indirect information about lung function.

All measures aim to prevent further lung damage and stabilize the baby’s lung function. Since a deficiency in surfactant is a primary factor in the development of BPD, it is administered via the trachea after delivery. Caffeine is also part of BPD treatment, as it can increase the infant’s respiratory drive. In addition to oxygen therapy, treating inflammation is a priority. The temporary administration of cortisone plays an important role in this regard.

If airway narrowing is present, inhalation therapy may be administered using medications that dilate the bronchi and keep the airways clear. If fluid retention (pulmonary edema) occurs, diuretic medications are used. Any increased pulmonary pressure that may occur is treated with vasodilators.

If the infant is able to tolerate it, physical therapy may also be considered as early as possible. This primarily includes breathing exercises, as well as specific positioning techniques. In addition, weight loss in premature infants is counteracted by an increased energy intake. 

The administration of calcium, phosphate, and vitamin D is particularly important. This helps prevent bone softening and the associated fragility (instability) of the chest wall.

If the premature infant requires mechanical ventilation for an extended period, a low-pressure ventilator is usually used. This allows the infant to be weaned off the ventilator gradually later on.

Before the child is discharged from the hospital, the first vaccinations—preferably against whooping cough and pneumococcal disease—should be administered. After the sixth month, an additional vaccination against influenza is recommended. There is also the option of a special vaccination against the RS virus, which is responsible for most respiratory infections in infants.

To prevent bronchopulmonary dysplasia (BPD), premature births should be avoided whenever possible. Pregnant women at risk of premature birth are therefore given corticosteroids to stimulate the maturation of the baby’s lungs and prevent inflammation. This preventive measure is known as lung maturation induction.

Mechanical ventilation is a major intervention that can lead to long-term damage to the lungs and brain @ Mark /AdobeStock

Thanks to advances in modern medicine, premature infants today have a high chance of surviving the condition. This is not the case only in a few instances involving severe disease progression and significant damage to the lungs or heart. Many babies even make a full recovery from the lung condition. The most significant improvement is usually seen within the first year of life.

However, there remains a tendency to develop respiratory illnesses. These primarily include bronchitis and pneumonia. That is why it is important to reduce the risk of infection for the child. In particular, large gatherings of people—such as in waiting rooms—should be avoided, especially during the winter months. Another risk factor is tobacco smoke, which can trigger inflammatory reactions or exacerbate existing inflammation. The same applies to emissions from heating appliances and wood-burning fireplaces.

After recovering from BPD, the child must attend follow-up appointments at regular intervals to monitor lung function and initiate any necessary treatments. In some cases, former preterm infants remain more susceptible to respiratory diseases well into adulthood.