What Is Bronchopulmonary Dysplasia (BPD)?

Bronchopulmonary Dysplasia

Premature infants who have problems in their respiratory system have an increased risk of bronchopulmonary dysplasia (BPD), which is also called chronic lung disease. Bronchopulmonary dysplasia (BPD) can be a serious condition, which needs intensive treatment. This condition most commonly occurs in babies that weigh less than 2 pounds and are born 10 weeks before due date. 

Babies are not born with bronchopulmonary dysplasia. The condition develops when premature babies with respiratory distress syndrome (RDS) need a breathing support for a long period of time. The extended use of a respirator and oxygen can damage the lungs. Although most babies tend to recover from BPD, some may develop chronic breathing difficulties.  

Causes

In most cases, BPD is caused by respiratory distress syndrome (RDS), which is a result of a particular lung development problem. The lungs of a premature baby are often not fully formed. To stay alive on their own, they cannot take in and absorb enough oxygen. A fluid called surfactant, which functions to keep the lungs open, may not be sufficiently produced, so the baby is given oxygen. 

However, it may be risky for newborns since their airways can get irritated and the air sacs that line the lungs can get scarred when a ventilator is used to pump oxygen into their lungs. When airway irritation and scarring of the lungs occur, premature babies have a harder time to breathe. 

Symptoms

The main symptom of BPD in infants is breathing much harder than normal. Moreover, the results of physical examination, pulmonary function testing, chest X-ray, and histopathology are abnormal. Shortly after birth, the initial findings observed are consistent with respiratory distress syndrome. If these abnormalities persist, then the risk of BPD also increases.

Babies born with BPD show signs and symptoms of respiratory distress syndrome (RDS), including:

• Tachycardia
• Tachypnea
• Labored breathing with nasal flaring, grunting, and retractions
• Frequent oxygen desaturations

Most of the time, these babies are extremely premature with a very low birth weight (VLBW) and a significant weight loss within the first 10 days of life. When they reach 2 weeks old, their need for oxygen and ventilatory support also tend to increase. Supplementation of oxygen, ventilator support, or both can be increased to keep oxygenation and ventilation stable at 2-4 weeks. 

Risk Factors

Below are some of the conditions that may help increase the chances of developing BPD:

• Degree of Prematurity - If the lungs are less developed, there is also an increased risk of lung damage, which may result in BPD. Infants born after 32 weeks of pregnancy may rarely develop BPD.

• High Concentrations of Supplemental Oxygen - There is an increased chance of developing BPD if the concentration of oxygen is higher and its supplementation is longer. An oxygen concentration of less than 60 percent is considered safe.

• Prolonged Mechanical Ventilation (PMV) - The alveoli can get stretched by mechanical ventilation. They can be damaged due to overstretching, especially for a longer period of time.

• Male Gender - Male infants have an increased risk of preterm birth and to develop BPD.

• Maternal Conditions - The normal growth of the fetus can be affected by maternal smoking, maternal malnutrition, use of illicit drugs, and infections during pregnancy. These conditions can cause premature labor and respiratory distress syndrome, which may lead to BPD.

• Patent Ductus Arteriosus (PDA) - It is an opening between two blood vessels from the heart. Ductus arteriosus is an opening and a normal part of an infant's circulatory system before being born. This opening usually closes soon after birth. However, if it remains open, it is called a patent ductus arteriosus. Problems do not often arise when there is a small patent ductus arteriosus, but an untreated large patent ductus arteriosus can allow poorly oxygenated blood to go in the wrong direction, which can weaken the heart muscle and cause heart failure and other serious complications. 

Diagnosis

There is no specific test that can be used to diagnose BPD. Blood tests and biopsies are not usually required. However, certain treatments can help delay, prevent, or reduce the symptoms. A BPD diagnosis is often based on the newborn's clinical status, the severity of prematurity, and the oxygen requirement according to age. 

After 28 days from birth, if infants still require supplemental oxygen and continue to display signs of breathing problems, BPD is usually diagnosed. A chest X-ray may also be helpful in a BPD diagnosis. Infants with RDS may show a ground-glass appearance of the lungs in their chest X-ray, while those with BPD may show a bubbly or a spongy-looking lung. 

Treatment

There are several types of treatment that can be used for the treatment of BPD, and they include:

• Bronchodilators: A bronchodilator is a type of medication that helps the muscles relax around the air passages, leading to easier breathing. They are usually given through nebulization or inhalation (inhaler with a spacer) in the form of a mist over the baby's face  

• Corticosteroids: These drugs can help prevent or reduce lung inflammation. Just like bronchodilators, corticosteroids are given as an aerosol either through nebulization or inhalation. 

• Diuretics: These drugs can help reduce the amount of fluid present in and around the alveoli. Diuretics are often orally administered 1-4 times a day. 

• Cardiovascular Medications: In some infants with BPD, certain medications that can help the muscles relax around the lung's blood vessels may be required. These drugs allow the blood to flow freely along with reducing heart strain. 

• Immunization: Infants with BPD usually have an increased risk of developing respiratory tract infections, particularly respiratory syncytial virus (RSV). Monthly injections with medications are given to infants with moderate to severe BPD to avoid contracting infections during the RSV season. 

Treatment for BPD is usually given in a hospital. An infant with BPD may be required to be in the hospital's neonatal intensive care unit (NICU) until respiratory problems are cleared. The average length of a NICU stay for babies with BPD is around 120 days.

Long-Term Outlook

Complications can arise due to BPD. They include aspiration or when food enters their lungs. Infants may also develop breathing difficulties due to respiratory illnesses, such as after getting a cold. 

At home, babies with BPD must have a healthy environment by keeping them away from air pollutants, such as cigarette smoke. Parents or caregivers should also limit the infant's exposure to harmful pathogens, such as viruses and bacteria. Additional oxygen supplementation may also be needed by some infants for some weeks to months after their hospital discharge. 

There are also many babies who completely recover from BPD.