Respiratory Distress Syndrome

Respiratory distress syndrome (RDS) is a breathing problem that sometimes affects babies born about 6 weeks or more before their due dates. Their lungs aren't developed enough to make surfactant. Surfactant is a liquid that coats the inside of the lungs and keeps them open so that the baby can breathe in air once he or she is born.

Without surfactant, the lungs collapse and the baby has to work hard to breathe. The baby might not be able to breathe in enough oxygen to support the body's organs.

Most infants who develop RDS show signs of breathing problems at birth or within the next few hours. If they're not given the right treatment, their brains and other organs may suffer from the lack of oxygen.

RDS is one of the most common lung disorders in premature babies. It affects about 10 of every 100 premature infants in the United States, or about 40,000 babies, each year. In fact, nearly all babies born before 28 weeks of pregnancy develop RDS. Full-term infants rarely get it.

RDS is different from bronchopulmonary dysplasia (BPD), another breathing condition that affects premature babies. While RDS usually develops in the first 24 hours after birth, BPD usually develops within the next week or two. Doctors aren't sure exactly what causes BPD, but they do know that most babies who develop it are born with serious RDS.

All of these babies lack surfactant. But the babies with RDS who go on to develop BPD have less developed lungs than the babies with RDS who recover. Their lungs usually have fewer, larger alveoli, with fewer tiny blood vessels than normal. The blood vessels are needed to move oxygen from the alveoli into the bloodstream.

Other Names

 * Hyaline membrane disease (HMD)
 * Neonatal respiratory distress syndrome
 * Infant respiratory distress syndrome

Causes
A lack of surfactant in a premature baby's lungs causes respiratory distress syndrome (RDS). Surfactant is a liquid that a fetus' lungs start making at around 26 to 34 weeks of pregnancy. It coats the insides of the lungs and keeps them open so they can breathe in air after birth. Without surfactant, the lungs collapse when the baby exhales. The baby then has to work hard to breathe.

Other factors that can increase the chances the baby will develop RDS include:


 * Premature Birth
 * Maternal Dibetes Mellitus
 * Cesarean delivery
 * Stress during delivery, especially hemorrhage (a large blood loss)
 * Infection

Some infants born at term develop RDS because they have abnormal genes for surfactant.

Signs and Symptoms
Signs and symptoms of respiratory distress syndrome (RDS) usually appear at birth or within the next few hours. They include:


 * Rapid, shallow breathing
 * Sharp pulling in of the chest below the ribs with each breath taken in
 * Grunting sounds during exhalation
 * Flaring of the nostrils during breathing

The baby may also stop breathing for a few seconds every now and then. This is called apnea.

Depending on how severe the RDS is, these babies also may develop other serious medical problems, including:


 * A collapsed lung.
 * Leakage of air from the lung into the chest cavity. This is rare.
 * Bronchopulmonary dysplasia, another lung disease in premature infants.
 * Bleeding in the brain, which can lead to delayed mental development,mental retardation, and cerebral palsy.
 * Sepsis, an infection of the bloodstream.
 * Bleeding in the lung.
 * Blindness and other eye problems.
 * Kidney failure, only in the most severe cases.
 * Necrotizing enterocolitis, a disease of the bowel.

Diagnosis
Doctors usually begin treating respiratory distress syndrome (RDS) as soon as the baby is born. At the same time, they do several tests to rule out any other conditions that could be causing the baby's breathing problems. The tests also can confirm that the doctors have diagnosed the condition correctly.

The tests include:


 * Chest x ray. A chest x ray takes a picture of the heart and lungs. It shows signs of RDS. A chest x ray also can identify complications, such as a collapsed lung, that may require urgent treatment.
 * Blood tests. Blood samples are checked to see whether the baby has enough oxygen in his or her blood. These tests also can rule out infection and sepsis as a cause of the breathing problems.
 * Echocardiogram. This test uses sound waves to create a moving picture of the heart. An echocardiogram is used to rule out congenital heart defects as the cause of the breathing problems.

Medications
Doctors usually give the baby antibiotics to control infections.

Therapies
Treatment of respiratory distress syndrome (RDS) usually begins as soon as the baby is born, sometimes in the delivery room. Most infants who show signs of RDS are quickly moved to a special intensive care unit called a neonatal intensive care unit (NICU). There they receive around-the-clock treatment from a group of health care professionals who specialize in treating premature infants.

The most important treatments for RDS are:


 * Surfactant replacement therapy
 * Breathing support

Surfactant Replacement Therapy
The baby is given surfactant until his or her lungs have developed enough to start making their own surfactant. Surfactant usually is given through a tube that's attached to a breathing machine. The machine pushes the surfactant directly into the baby's lungs.

Surfactant may be given right after birth in the delivery room to try to prevent or treat RDS. It can be given two to four more times over the next few days, until the baby is able to breathe on his or her own.

Breathing Support
Babies with RDS often are put on a machine that helps them breathe until their lungs have developed enough to start making their own surfactant. Until recently, these babies usually were put on a mechanical ventilator that was connected to a breathing tube that ran through the baby's mouth or nose into the windpipe.

Today, more and more babies are receiving breathing support from a nasal continuous positive airway pressure (NCPAP) machine, which pushes air into the baby's lungs through prongs in the nostrils.

Other Types of Treatment
Other treatments for babies with RDS include:


 * Medicines
 * Supportive therapy
 * Treatment for patent ductus arteriosus, a condition that affects some premature infants

Supportive Therapy
Treatment in the NICU is designed to limit stress on the baby and meet his or her basic needs of warmth, nutrition, and protection. Such treatment usually includes:


 * Using a radiant warmer or incubator to keep the baby warm and reduce the chances of infection.
 * Ongoing monitoring of blood pressure, heart rate, breathing, and temperature through sensors taped to the baby's body.
 * Using a sensor on a finger or toe to monitor the amount of oxygen in the baby's blood.
 * Giving fluids and nutrients through a needle or tube inserted into a vein to prevent malnutrition and promote growth. Nutrition is critical to the growth and development of the lungs. Later, your baby may be given milk through a tube that's passed through his or her nose into the mouth.
 * Monitoring fluid intake to make sure that fluid doesn't build up in the baby's lungs.

Prevention
There are certain things that can be done to ensure that a baby isn't born before his or her lungs have developed completely.

They include:


 * Seeing the doctor regularly during pregnancy
 * Eating right
 * Avoiding tobacco smoke, alcohol, and illegal drugs
 * Controlling any ongoing medical conditions you have
 * Preventing infection

The doctor may give injections of a corticosteroid medicine if it looks as though birth may occur too early. This medicine can speed up surfactant production and development of the lungs, brain, and kidneys in the fetus. Usually, within about 24 hours after the medicine is started, the fetus' lungs start making enough surfactant, and the baby's chances of developing respiratory distress syndrome (RDS) are reduced. If the baby does develop RDS, it will probably be relatively mild.

If this medicine at least 15 hours before delivering, it also can reduce the chances that the baby will have any bleeding into the brain or develop necrotizing enterocolitis, a serious condition that affects the baby's intestines.

Living With Respiratory Distress Syndrome
Caring for a premature infant can be challenging. Any of the following may occur:


 * Emotional pain, including feelings of guilt, anger, and depression
 * Anxiety about the baby's future
 * A feeling of a lack of control over the situation
 * Financial stress
 * Problems relating to the baby in the neonatal intensive care unit (NICU)
 * Fatigue (tiredness)

Things that can be done:
 * Breast feeding the baby.
 * Learning as much as possible about what goes on in the NICU in order to help the baby during his or her stay there and begin to bond with the baby before he or she comes home.
 * Learning as much as possible about the baby's condition and what is involved in daily care so the right questions can be asked. This will help to build confidence for when it is time to take the baby home.
 * Seeking out support from family and friends, as well as hospital personnel. Ask the case manager or social worker at the hospital about what will be needed after the baby leaves the hospital. The physicians and nursing staff can assist with questions about infant care. Also ask whether there is a support group in the community.
 * Enjoying the new baby, spending as much time with him or her as possible, and looking forward to a happy future.

The baby also may need special care after leaving the NICU, including:


 * Special hearing and eye examinations
 * Speech or physical therapy
 * Specialty care for other medical problems caused by premature birth

Clinical Trials

 * Current Research (ClinicalTrials.gov)
 * Patient Recruitment for Studies Conducted by the NHLBI, NIH

Expected Outcome
Thanks to recent medical advances, most babies with RDS who weigh more than 2 pounds at birth now survive and have no long-term health or development problems.

Other Resources

 * Bronchopulmonary Dysplasia (Diseases and Conditions Index)
 * Lung Information for the Public
 * Respiratory Distress Syndrome (MedlinePlus)