BRONCHOPULMONARY DYSPLASIA DEFINITION
Bronchopulmonary dysplasia (BPD) is a form of chronic lung disease that affects newborns (mostly premature) and infants. It results from damage to the lungs caused by mechanical ventilation (respirator) and long-term use of oxygen. Most infants recover from BPD, but some may have long-term breathing difficulty.
BRONCHOPULMONARY DYSPLASIA CAUSES
Bronchopulmonary dysplasia (BPD) develops as a result of an infant’s lungs becoming irritated or inflamed.
The lungs of premature infants are fragile and often aren’t fully developed. They can easily be irritated or injured within hours or days of birth. Many factors can damage premature infants’ lungs.
Newborns who have breathing problems or can’t breathe on their own may need ventilator support. Ventilators are machines that use pressure to blow air into the airways and lungs.
Although ventilator support can help premature infants survive, the machine’s pressure might irritate and harm the babies’ lungs. For this reason, doctors only recommend ventilator support when necessary.
HIGH LEVELS OF OXYGEN
Newborns who have breathing problems might need oxygen therapy (oxygen given through nasal prongs, a mask, or a breathing tube). This treatment helps the infants’ organs get enough oxygen to work well.
However, high levels of oxygen can inflame the lining of the lungs and injure the airways. Also, high levels of oxygen can slow lung development in premature infants.
Infections can inflame the lungs. As a result, the airways narrow, which makes it harder for premature infants to breathe. Lung infections also increase the babies’ need for extra oxygen and breathing support.
Studies show that heredity may play a role in causing BPD. More studies are needed to confirm this finding.
BRONCHOPULMONARY DYSPLASIA PATHOPHYSIOLOGY
The pathogenesis of bronchopulmonary dysplasia remains complex and poorly understood. Bronchopulmonary dysplasia results from various factors that can injure small airways and that can interfere with alveolarization (alveolar septation), leading to alveolar simplification with a reduction in the overall surface area for gas exchange. The developing pulmonary microvasculature can also be injured. Alveolar and lung vascular development are intimately related, and injury to one may impair development of the other. Damage to the lung during a critical stage of lung growth can result in clinically significant pulmonary dysfunction.
Premature birth and subsequent events (eg, exposure to oxygen, mechanical ventilation, inflammatory agents, infection) likely shifts the balance from lung development consisting of lung alveolar and vascular growth to one of premature maturation, which is associated with an arrest in development and a loss of future gas exchange area; however, alveolar maturation might facilitate gas exchange in the short-term.
BRONCHOPULMONARY DYSPLASIA SYMPTOMS
Many babies who develop bronchopulmonary dysplasia (BPD) are born with serious respiratory distress syndrome (RDS). The signs and symptoms of RDS at birth are:
- Rapid, shallow breathing
- Sharp pulling in of the chest below and between the ribs with each breath
- Grunting sounds
- Flaring of the nostrils
Babies who have RDS are treated with surfactant replacement therapy. They also may need oxygen therapy (oxygen given through nasal prongs, a mask, or a breathing tube).
Shortly after birth, some babies who have RDS also are treated with nasal continuous positive airway pressure (NCPAP) or ventilators(machines that support breathing).
Often, the symptoms of RDS start to improve slowly after about a week. However, some babies get worse and need more oxygen or breathing support from NCPAP or a ventilator.
A first sign of BPD is when premature infants—usually those born more than 10 weeks early—still need oxygen therapy by the time they reach their original due dates. These babies are diagnosed with BPD.
Infants who have severe BPD may have trouble feeding, which can lead to delayed growth. These babies also may develop:
- Pulmonary hypertension (PH). PH is increased pressure in the pulmonary arteries. These arteries carry blood from the heart to the lungs to pick up oxygen.
- Corpulmonale. Corpulmonale is failure of the right side of the heart. Ongoing high blood pressure in the pulmonary arteries and the lower right chamber of the heart causes this condition.
BRONCHOPULMONARY DYSPLASIA DIAGNOSIS
Infants who are born early—usually more than 10 weeks before their due dates—and still need oxygen therapy by the time they reach their original due dates are diagnosed with bronchopulmonary dysplasia (BPD).
BPD can be mild, moderate, or severe. The diagnosis depends on how much extra oxygen a baby needs at the time of his or her original due date. It also depends on how long the baby needs oxygen therapy.
To help confirm a diagnosis of BPD, doctors may recommend tests, such as:
- Chest x ray. A chest x ray takes pictures of the structures inside the chest, such as the heart and lungs. In severe cases of BPD, this test may show large areas of air and signs of inflammation or infection in the lungs. A chest x ray also can detect problems (such as a collapsed lung) and show whether the lungs aren’t developing normally.
- Blood tests. Blood tests are used to see whether an infant has enough oxygen in his or her blood. Blood tests also can help determine whether an infection is causing an infant’s breathing problems.
- Echocardiography. This test uses sound waves to create a moving picture of the heart. Echocardiography is used to rule out heart defects or pulmonary hypertension as the cause of an infant’s breathing problems
BRONCHOPULMONARY DYSPLASIA TREATMENT
If your doctor thinks you’re going to give birth too early, he or she may give you injections of a corticosteroid medicine.
The medicine can speed up surfactant production in your baby. Surfactant is a liquid that coats the inside of the lungs. It helps keep the lungs open so your infant can breathe in air once he or she is born.
Corticosteroids also can help your baby’s lungs, brain, and kidneys develop more quickly while he or she is in the womb.
Premature babies who have very low birth weights also might be given corticosteroids within the first few days of birth. Doctors sometimes prescribe inhaled nitric oxide shortly after birth for babies who have very low birth weights. This treatment can help improve the babies’ lung function.
These preventive measures may help reduce infants’ risk of respiratory distress syndrome (RDS), which can lead to BPD.
TREATMENT FOR RESPIRATORY DISTRESS SYNDROME
The goals of treating infants who have RDS include:
- Reducing further injury to the lungs
- Providing nutrition and other support to help the lungs grow and recover
- Preventing lung infections by giving antibiotics
Treatment of RDS usually begins as soon as an infant is born, sometimes in the delivery room. Most infants who have signs of RDS are quickly moved to a neonatal intensive care unit (NICU). They receive around-the-clock treatment from health care professionals who specialize in treating premature infants.
Treatments for RDS include surfactant replacement therapy, breathing support with nasal continuous positive airway pressure(NCPAP) or a ventilator, oxygen therapy (oxygen given through nasal prongs, a mask, or a breathing tube), and medicines to treat fluid buildup in the lungs.
For more information about RDS treatments, go to the Health Topics Respiratory Distress Syndrome article.
TREATMENT FOR BRONCHOPULMONARY DYSPLASIA
Treatment in the NICU is designed to limit stress on infants and meet their basic needs of warmth, nutrition, and protection. Once doctors diagnose BPD, some or all of the treatments used for RDS will continue in the NICU.
Such treatment usually includes:
- Using radiant warmers or incubators to keep infants warm and reduce the risk of infection.
- Ongoing monitoring of blood pressure, heart rate, breathing, and temperature through sensors taped to the babies’ bodies.
- Using sensors on fingers or toes to check the amount of oxygen in the infants’ blood.
- Giving fluids and nutrients through needles or tubes inserted into the infants’ veins. This helps prevent malnutrition and promotes growth. Nutrition is vital to the growth and development of the lungs. Later, babies may be given breast milk or infant formula through feeding tubes that are passed through their noses or mouths and into their throats.
- Checking fluid intake to make sure that fluid doesn’t build up in the babies’ lungs.
As BPD improves, babies are slowly weaned off NCPAP or ventilators until they can breathe on their own. These infants will likely need oxygen therapy for some time.
If your infant has moderate or severe BPD, echocardiography might be done every few weeks to months to check his or her pulmonary artery pressure.
If your child needs long-term ventilator support, he or she will likely get a tracheostomy (TRA-ke-OS-toe-me). A tracheostomy is a surgically made hole. It goes through the front of the neck and into the trachea (TRA-ke-ah), or windpipe. Your child’s doctor will put the breathing tube from the ventilator through the hole.
Using a tracheostomy instead of an endotracheal (en-do-TRA-ke-al) tube has some advantages. (An endotracheal tube is a breathing tube inserted through the nose or mouth and into the windpipe.)
Long-term use of an endotracheal tube can damage the trachea. This damage may need to be corrected with surgery later. A tracheostomy can allow your baby to interact more with you and the NICU staff, start talking, and develop other skills.
While your baby is in the NICU, he or she also may need physical therapy. Physical therapy can help strengthen your child’s muscles and clear mucus out of his or her lungs.
Infants who have BPD may spend several weeks or months in the hospital. This allows them to get the care they need.
Before your baby goes home, learn as much as you can about your child’s condition and how it’s treated. Your baby may continue to have some breathing symptoms after he or she leaves the hospital.
Your child will likely continue on all or some of the treatments that were started at the hospital, including:
- Medicines, such as bronchodilators, steroids, and diuretics.
- Oxygen therapy or breathing support from NCPAP or a ventilator.
- Extra nutrition and calories, which may be given through a feeding tube.
- Preventive treatment with a medicine called palivizumab for severe respiratory syncytial virus (RSV). This common virus leads to mild, cold-like symptoms in adults and older, healthy children. However, in infants—especially those in high-risk groups—RSV can lead to severe breathing problems.
Your child also should have regular checkups with and timely vaccinations from a pediatrician. This is a doctor who specializes in treating children. If your child needs oxygen therapy or a ventilator at home, a pulmonary specialist might be involved in his or her care.
Seek out support from family, friends, and hospital staff. Ask the case manager or social worker at the hospital about what you’ll need after your baby leaves the hospital.
The doctors and nurses can assist with questions about your infant’s care. Also, you may want to ask whether your community has a support group for parents of premature infants.