Neonatal Respiratory Distress Syndrome

Neonatal respiratory distress syndrome is a serious breathing problem that primarily affects premature babies whose lungs haven’t fully developed, making it hard for them to get enough oxygen shortly after birth.

Table of contents

• What is Neonatal Respiratory Distress Syndrome?
• Why Does It Happen?
• Who Is at Risk?
• Signs and Symptoms
• How Is It Diagnosed?
• Treatment Options
• Possible Complications
• What to Expect

What is Neonatal Respiratory Distress Syndrome?

RDS, infant respiratory distress syndrome, hyaline membrane disease, surfactant deficiency lung disease

Neonatal respiratory distress syndrome, often called RDS, is a common breathing disorder that affects newborn babies^[1]. This condition makes it hard for babies to breathe and get enough oxygen into their blood^[6]. RDS is one of the most common problems seen in premature babies, and it typically presents within hours after birth, most often immediately after delivery^[1].

The condition occurs most often in babies born before their due date, usually before 28 weeks of pregnancy^[6]. However, it can also affect babies born later in pregnancy. The earlier a baby is born, the more likely they are to develop RDS and need extra oxygen and help breathing^[2].

Most newborns who have RDS survive with proper treatment^[6]. More than 90 percent of babies with this condition recover^[8]. While treatment methods including antenatal corticosteroids (steroids given to mothers before premature birth), surfactants (substances that help lungs work properly), and advanced respiratory care have improved outcomes for affected babies, RDS continues to be a leading cause of illness and death in premature infants^[1].

Why Does It Happen?

Neonatal RDS occurs when a baby’s lungs haven’t produced enough of a substance called surfactant^[4]. Surfactant is a slippery, liquid substance made up of proteins and fats that helps keep the lungs inflated and prevents them from collapsing^[4].

This important substance coats the tiny air sacs in the lungs, called alveoli, and helps keep them from collapsing^[2]. The air sacs must be open to allow oxygen to enter the blood from the lungs and carbon dioxide to be released from the blood into the lungs^[2].

A baby normally begins producing surfactant sometime between weeks 24 and 28 of pregnancy^[4]. The lungs make more surfactant as the baby grows. Surfactant is produced in the lungs at about 26 weeks of pregnancy, and it begins to be found in amniotic fluid (the fluid surrounding the baby) between 28 and 32 weeks^[8]. Most babies produce enough surfactant to breathe normally by week 34^[4], and by about 35 weeks of pregnancy, most babies have developed adequate amounts^[8].

If a baby is born prematurely, they may not have enough surfactant in their lungs^[4]. Their alveoli can’t stay open to fill with air^[9]. When there is not enough surfactant, the tiny alveoli collapse with each breath^[7]. As the alveoli collapse, damaged cells collect in the airways and further affect breathing ability^[7]. The baby works harder and harder at breathing, trying to reinflate the collapsed airways^[7].

As the baby’s lung function decreases, less oxygen is taken in and more carbon dioxide builds up in the blood. This can lead to increased acid in the blood called acidosis, a condition that can affect other body organs^[7].

Occasionally, RDS affects babies that are not born prematurely^[4]. Rarely, babies born at 39 weeks or later can develop RDS^[9]. A variety of reasons can cause this, such as a mother’s high blood sugar during pregnancy, pneumonia, some complications during birth, or genetic changes^[9]. The condition can also be due to genetic problems with lung development^[3].

Who Is at Risk?

The incidence of RDS is inversely proportional to the gestational age of the infant, with more severe disease in the smaller and more premature babies^[1]. The biggest risk factor for neonatal respiratory distress syndrome is preterm birth^[9]. It’s most common in babies born before 32 weeks of pregnancy, but not uncommon after 32 weeks and before full term^[9].

Most cases of RDS occur in babies born before 37 to 39 weeks. The more premature the baby is, the higher the chance of RDS after birth^[3]. Around half of all babies born between 28 and 32 weeks of pregnancy develop RDS^[4]. The problem is uncommon in babies born full-term or later, at 39 weeks or after^[3].

While RDS is most common in babies born early, other newborns can get it. Those at greater risk include^[2]:

• Siblings that had RDS
• Twin or multiple births
• Babies delivered by cesarean section (C-section)
• Babies whose mother has diabetes
• Babies with infection
• Babies that are sick at the time of delivery
• Babies experiencing cold, stress, or hypothermia, who cannot keep body temperature warm at birth

Your baby might be at higher risk if you have diabetes while pregnant, they have a biological sibling with RDS, or it’s a multiples pregnancy like twins or triplets^[9]. Other factors that can increase the risk include problems with delivery that reduce blood flow to the baby and rapid labor^[3].

If your child is at higher risk for RDS, your pregnancy care provider might give you corticosteroids while pregnant. This can help increase the level of surfactant in the baby’s lungs before birth^[9]. In recent years, the number of premature babies born with RDS has been reduced with the use of steroid injections, which can be given to mothers during premature labor^[4]. Steroids help the baby’s lungs mature and make more surfactant before the baby is born^[4]. It’s estimated that this treatment helps prevent RDS in a third of premature births^[4].

Signs and Symptoms

The symptoms of RDS are often noticeable immediately after birth and get worse over the following few days^[4]. Signs of neonatal RDS are usually noticeable within a few hours of birth^[9]. Most of the time, symptoms appear within minutes of birth. However, they may not be seen for several hours^[3].

Babies who have RDS may show these signs^[2]:

• Fast breathing very soon after birth
• Grunting “ugh” sound with each breath
• Changes in color of lips, fingers and toes
• Widening (flaring) of the nostrils with each breath
• Chest retractions – skin over the breastbone and ribs pulls in during breathing

Additional symptoms may include^[3]:

• Bluish color of the skin and mucus membranes, called cyanosis
• Brief stop in breathing, called apnea
• Decreased urine output
• Rapid breathing, also called tachypnea
• Shallow breathing
• Shortness of breath
• Unusual breathing movement such as drawing back of the chest muscles with breathing

Your baby’s breathing might be fast and/or shallow, or there might be pauses in their breathing. You might also notice bluish or greyish skin, lips or nails, flaring nostrils, grunting, and skin pulling in between their ribs when they breathe^[9].

How Is It Diagnosed?

A healthcare team checks your baby’s health when they’re born. They’ll look for signs of neonatal RDS^[9]. Health care providers will suspect RDS in a premature baby who has trouble breathing and needs oxygen soon after birth^[2].

The diagnosis is made after examining the baby and seeing the results of chest X-rays and blood tests^[2]. A number of tests can be used to diagnose RDS and rule out other possible causes^[4].

These tests include^[4]:

• A physical examination
• Blood tests to measure the amount of oxygen in the baby’s blood and check for an infection
• A pulse oximetry test to measure how much oxygen is in the baby’s blood using a sensor attached to their fingertip, ear or toe
• A chest X-ray to look for the distinctive cloudy appearance of the lungs in RDS

Blood gas analysis shows low oxygen and excess acid in the body fluids^[3]. Chest X-rays show a “ground glass” appearance to the lungs that is typical of the disease. This often develops 6 to 12 hours after birth^[3]. In RDS, X-rays often show a unique “ground glass” appearance called a reticulogranular pattern^[8].

Additional tests may include an echocardiography (EKG), which may be used to rule out heart problems that could cause symptoms similar to RDS. An electrocardiogram is a test that records the electrical activity of the heart, shows abnormal rhythms, and detects damage to the heart muscle^[8]. Lab tests help to rule out infection as a cause of breathing problems^[3].

Treatment Options

A healthcare team will monitor your baby closely if they have respiratory distress syndrome^[9]. The main aim of treatment for RDS is to help the baby breathe^[4]. Babies who are premature or have other conditions that make them at high risk for the problem need to be treated at birth by a medical team that specializes in newborn breathing problems^[3].

Your baby may be transferred to a ward that provides specialist care for premature babies, called a neonatal unit^[4].

Oxygen and Breathing Support

Babies with RDS need extra oxygen^[2]. Infants will be given warm, moist oxygen. However, this treatment needs to be monitored carefully to avoid side effects from too much oxygen^[3]. Room air is 21% oxygen. Your baby needs higher oxygen to stay pink^[24].

Oxygen may be given several ways^[2]:

• Nasal cannula: A small tube with prongs is placed in the nostrils
• Continuous Positive Airway Pressure (CPAP): This machine gently pushes air or oxygen into the lungs to keep the air sacs open
• Ventilator (for severe RDS): This is a machine that helps the infant breathe when they cannot breathe well enough without help. A breathing tube is put down the infant’s windpipe. This is called intubation. The infant is then placed on the ventilator to help them breathe

If the symptoms are mild, babies may only need extra oxygen. It’s usually given through an incubator, a small mask over their nose or face, or tubes into their nose^[4]. CPAP sends air into the nose to help keep the airways open. It can be given by a ventilator while the baby is breathing independently or with a separate CPAP device^[3].

If symptoms are more severe, your baby will be attached to a breathing machine (ventilator) to either support or take over their breathing^[4]. Assisted ventilation with a ventilator can be lifesaving for some babies. However, use of a breathing machine can damage the lung tissue, so this treatment should be avoided if possible^[3].

A treatment called continuous positive airway pressure (CPAP) may prevent the need for assisted ventilation or surfactant in many babies^[3]. In the delivery room, nasal CPAP is often used in spontaneously breathing premature infants immediately after birth as a potential alternative to immediate intubation and surfactant replacement^[12].

Surfactant Therapy

They’ll give your baby surfactant to help open their alveoli. There are different techniques that their provider might use to do this^[9]. Your baby may be given a dose of artificial surfactant, usually through a breathing tube^[4].

Giving extra surfactant to a sick infant has been shown to be helpful. However, the surfactant is delivered directly into the baby’s airway, so some risk is involved^[3]. Evidence suggests early treatment within 2 hours of delivery is more beneficial than if treatment is delayed^[4]. This treatment has been shown to reduce the severity of RDS, and is most effective if started in the first six hours of birth^[8].

Using the INSURE technique, the newborn is intubated, given surfactant, and quickly extubated to nasal continuous positive airway pressure^[5]. This strategy should be used to reduce mechanical ventilation, air leak syndromes, and progression to bronchopulmonary dysplasia (a chronic lung condition)^[5].

Additional Care

Your baby may have an umbilical arterial catheter (UAC) and/or an umbilical venous catheter (UVC) placed. This consists of placing a very small piece of tubing into one or two of the blood vessels in the baby’s umbilical cord stump^[24]. These catheters are used to give the infant needed fluids, medications, and nutrients, and to obtain blood samples without having to repeatedly stick the baby^[24].

Your baby will be hooked up to one or more monitors. Wires will connect patches on your baby to the monitors. Your baby will be in a special bed to help keep them warm^[24].

They’ll also be given fluids and nutrition through a tube connected to a vein^[4]. Babies with RDS need closely monitored care, which includes having a calm setting, gentle handling, staying at an ideal body temperature, carefully managing fluids and nutrition, and treating infections right away^[3].

Possible Complications

Most babies with RDS can be successfully treated, although they have a high risk of developing further problems later in life^[4]. Neonatal respiratory distress can cause complications in your baby’s organs^[9].

Possible complications include^[9]:

• Bleeding in their brain, which can cause permanent damage
• Bleeding in their lungs
• Buildup of air around your baby’s lungs, between their lungs or between their heart and the sac around it (pneumothorax)
• Lung inflammation and scarring (bronchopulmonary dysplasia)
• Vision issues

Air can sometimes leak out of the baby’s lungs and become trapped in their chest cavity, known as pneumothorax^[4]. The pocket of air places extra pressure on the lungs, causing them to collapse and leading to additional breathing problems. Air leaks can be treated by inserting a tube into the chest to allow the trapped air to escape^[4].

Long-term complications may develop due to too much oxygen, high pressure delivered to the lungs, more severe disease or immaturity, or periods when the brain or other organs did not get enough oxygen^[3]. RDS can be associated with inflammation that causes lung or brain damage^[3].

Some infants with severe respiratory distress syndrome will die. This most often occurs between days 2 and 7^[3].

What to Expect

For each baby the course is different^[24]. The course of illness with respiratory distress syndrome depends on the size and gestational age of the baby, the severity of the disease, the presence of infection, whether or not a baby has a patent ductus arteriosus (a heart condition), and whether or not the baby needs mechanical help to breathe^[7].

RDS typically worsens over the first 48 to 72 hours, then improves with treatment^[7]. The disease usually gets worse for about 3-4 days. Then, the baby gradually needs less added oxygen^[24]. The condition often gets worse for 2 to 4 days after birth and improves slowly after that^[3].

If a baby has relatively mild disease and has not needed a breathing machine, they may be off oxygen in 5-7 days^[24]. Some babies with RDS only need help with breathing for a few days. But some, usually those born extremely prematurely, may need support for weeks or even months^[4].

If a baby has more severe disease, there is also improvement after 3-5 days but the improvement may be slower and the baby may need extra oxygen and/or a ventilator for days to weeks^[24]. Recovery is slower if the baby is very tiny (less than 2½ pounds at birth), the baby’s disease was severe, the baby also had infection, or the baby had complications^[24].

Premature babies often have multiple problems that keep them in hospital, but generally they’re well enough to go home around their original expected delivery date^[4]. The length of time your baby needs to stay in hospital will depend on how early they were born^[4].

Long term problems are more likely if the disease has been severe or if there have been complications. Possible problems may include increased severity of colds or other respiratory infections^[24].