Respiratory Distress Syndrome (Newborn)

What surfactant does

The lungs contain millions of tiny air sacs (alveoli). Surfactant is a mix of fats and proteins that lowers surface tension so the sacs stay open when breathing out. The baby's lungs start making surfactant around 24 to 28 weeks of pregnancy, with enough for normal breathing usually by about 34 to 36 weeks.

In RDS, the lungs lack surfactant, so:

• air sacs collapse at the end of each breath
• the baby must work very hard to reopen them
• oxygen levels fall and carbon dioxide builds up
• protein-rich fluid leaks into the lungs, forming "hyaline membranes" seen under a microscope

Who is at risk

• prematurity: the strongest risk factor; the earlier the birth, the higher the risk
• maternal diabetes, which delays lung maturity
• cesarean delivery without labor, especially before 39 weeks
• male sex and white race (slightly higher risk)
• multiple births
• a sibling who had RDS
• low oxygen or stress at birth
• rare genetic surfactant deficiencies in full-term babies

Signs and symptoms

Signs usually start within minutes to a few hours after birth and worsen over the first 1 to 2 days:

• fast breathing (more than 60 breaths a minute)
• grunting with each breath
• nostril flaring
• chest retractions: skin pulling in between and under the ribs
• blue or gray color around the lips and skin (cyanosis)
• pauses in breathing (apnea)
• reduced urine output and swelling

Other causes of breathing difficulty in newborns

Diagnosis

• examination of breathing effort and oxygen levels
• chest X-ray: shows a hazy "ground glass" appearance with air bronchograms
• blood gas tests: low oxygen, high carbon dioxide
• tests to rule out infection

Prevention

• antenatal corticosteroids: steroid injections (betamethasone or dexamethasone) given to the mother when preterm birth between about 24 and 34 weeks is expected speed up lung maturity and greatly reduce RDS, brain bleeding and death
• delaying delivery when safe, and avoiding elective cesarean before 39 weeks
• good diabetes control in pregnancy

Treatment

Treated in a neonatal intensive care unit (NICU):

• CPAP (continuous positive airway pressure): gentle air pressure through the nose keeps air sacs open; often started in the delivery room
• surfactant replacement: given into the lungs through a breathing tube or a thin catheter (less invasive surfactant administration); improves breathing within hours
• oxygen, carefully adjusted to avoid too much, which can harm the eyes and lungs
• mechanical ventilation for babies who need more support
• supportive care: warmth, IV fluids and nutrition, monitoring, and antibiotics until infection is ruled out

Symptoms usually peak in 2 to 3 days and then improve as the baby begins making its own surfactant.

Complications

• air leaks such as pneumothorax
• bronchopulmonary dysplasia, a chronic lung disease in very premature babies
• brain bleeding (intraventricular hemorrhage)
• patent ductus arteriosus
• retinopathy of prematurity
• infections

Many of these relate to prematurity itself, not only RDS.

Outlook

With modern care, most babies with RDS survive and recover, especially those born after 28 weeks. The most premature babies have higher risks of long-term lung and developmental problems. Follow-up includes growth, development, hearing and vision checks. Neonatal RDS is different from acute respiratory distress syndrome (ARDS) in older children and adults, which is caused by lung injury.

Frequently asked questions

What causes respiratory distress syndrome in newborns?

It is caused by a lack of surfactant in the baby's immature lungs, which lets the tiny air sacs collapse. It mainly affects premature babies, especially those born before 34 weeks. Maternal diabetes and cesarean birth before labor also raise the risk.

What are the signs of respiratory distress in a newborn?

Signs include fast breathing, grunting, flaring nostrils, skin pulling in between the ribs, blue or gray color and pauses in breathing. They usually appear within minutes to hours of birth.

How is neonatal RDS treated?

Babies are treated in the NICU with CPAP to keep the lungs open, surfactant given into the lungs, oxygen and, if needed, a ventilator. Most improve within a few days as their lungs start producing surfactant.

Can respiratory distress syndrome be prevented?

The risk can be greatly reduced. If preterm birth is expected, steroid injections given to the mother at least 24 hours before delivery help the baby's lungs mature. Avoiding early elective cesarean and managing diabetes also help.

Does RDS cause long-term problems?

Many babies recover fully. Very premature babies have a higher risk of chronic lung disease (bronchopulmonary dysplasia) and other complications of prematurity, so they need follow-up of breathing, growth and development.