Chronic Lung Disease

What is chronic lung disease?

Chronic lung disease (CLD) is a general term for long-term respiratory problems in premature babies. It is also known as bronchopulmonary dysplasia (BPD).

What causes chronic lung disease?

CLD results from lung injury to newborns who must use a mechanical ventilator and extra oxygen for breathing. The lungs of premature babies are fragile and are easily damaged. With injury, the tissues inside the lungs become inflamed and can break down causing scarring. This scarring can result in difficulty breathing and increased oxygen needs. Some of the causes of lung injury include the following:

• Prematurity--the lungs, especially the air sacs, are not fully developed

• Low amounts of surfactant (a substance in the lungs that helps keep the tiny air sacs open)

• Oxygen use (high concentrations of oxygen can damage the cells of the lungs)

• Mechanical ventilation--the pressure of air from breathing machines, suctioning of the airways, use of an endotracheal tube (ET tube--a tube placed in the trachea and connected to a breathing machine)

Who is affected by chronic lung disease?

Chronic lung disease can develop in premature babies who have had mechanical ventilation (breathing machine). Risk factors for developing CLD include:

• Birth at less than 30 weeks gestation

• Birthweight less than 1,000 (less than 2 pounds) to 1,500 grams (3 pounds 5 ounces)

• Hyaline membrane disease--lung disease of prematurity due to lack of surfactant that does not show the usual improvement by the third or fourth day.

• Pulmonary interstitial emphysema (PIE)--a problem in which air leaks out of the airways into the spaces between the small air sacs of the lungs.

• Patent ductus arteriosus (PDA)--a connection between the blood vessels of the heart and lungs that does not close as it should after birth.

• Premature Caucasian, male babies are at greater risk for developing BPD

• Maternal womb infection (chorioamnionitis)

• A family history of asthma

• Breathing problems at birth

• Develop an infection during or shortly after birth

What are the symptoms of chronic lung disease?

The following are the most common symptoms of CLD. However, each baby may experience different symptoms of the condition. Symptoms may include:

• Respiratory distress (rapid breathing, flaring of the nostrils, grunting, chest retractions)

• Continued need for mechanical ventilation or oxygen after a premature baby reaches 36 weeks gestation

The symptoms of CLD may resemble other conditions or medical problems. Always consult your baby's doctor for a diagnosis.

How is chronic lung disease diagnosed?

Because CLD is a chronic disease and appears gradually, doctors must look at several factors. It is often diagnosed when a premature baby with respiratory problems continues to need additional oxygen after reaching 28 days of age. Chest X-rays compared with previous X-rays may show changes in the appearance of the lungs. The X-ray of lungs with CLD often have a bubbly, sponge-like appearance. X-rays are diagnostic tests which use invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.

Blood tests (test used to determine if enough oxygen is in the blood) and an echocardiography (test that use sound waves to create images of the heart to rule out defects) are also used to confirm causes of bronchopulmonary dysplasia.

Treatment of chronic lung disease 

Specific treatment for CLD will be determined by your baby's doctor based on:

• Your baby's gestational age, overall health, and medical history

• Extent of the disease

• Your baby's tolerance for specific medications, procedures, or therapies

• Expectations for the course of the disease

• Your opinion or preference

Treatment of CLD may include:

• Extra oxygen (to make up for the decreased breathing ability of the damaged lungs) and a pulse oximeter to measure how much oxygen is in the blood

• Mechanical ventilation with gradual weaning as the baby's lungs grow and can do more of the work of breathing

• Surfactant replacement

• Medications such as:

  • Bronchodilators (to help open the airways)

  • Steroids (to help to reduce inflammation)

  • Diuretics (to help reduce excess fluid in the lungs)

  • Antibiotics (to fight an infection)

• Intravenous fluids and nutrition (to help the baby and the lungs grow). It is important to monitor the fluid intake, because excess fluids can build up in the lungs and worsen the infant's breathing ability

• Radiant warmers or incubators to keep the infant warm and decrease the risks of developing an infection

• Nutrition (to help the baby and the lungs grow)

• Immunization against lung infection by respiratory syncytial virus (RSV) and influenza

CLD can be a long-term condition. Some babies with CLD require mechanical ventilators for several months. Some babies will continue to require oxygen when they go home from the hospital, but most can be weaned from oxygen by the end of their first year. Babies with CLD may be at increased risk for respiratory infection and may have to be re-hospitalized.