Newborn respiratory distress syndrome

This is the condition in which a newborn baby's lungs cannot expand properly, so that breathing is hard work from the first minutes of life. Other names are used for it — respiratory distress syndrome, hyaline membrane disease, surfactant deficiency — but they all mean the same thing. It is not inflammation and not an infection: the lungs simply have not had time to mature, which is why the condition belongs almost entirely to babies born early. Despite the similar name, it has nothing to do with acute respiratory distress syndrome in adults. It stopped being a sentence long ago: steroids given before birth, breathing support and artificial surfactant have changed the outlook beyond recognition.

Why the lungs run short of surfactant

Inside, the tiny air sacs of the lungs — the alveoli — are lined with a thin film of fats and proteins called surfactant. It has one job: to stop the air sac collapsing as the baby breathes out. Without it the walls stick together and every breath has to be taken afresh, like the very first one, with enormous effort.

Surfactant begins to be made at around 24 weeks of pregnancy, but the amount that allows quiet, easy breathing accumulates closer to 34 to 36 weeks. A baby born before that meets the first breath with a half-empty store, and the earlier the birth, the sharper the shortfall: below 28 weeks nearly every baby is affected, between 28 and 32 weeks around half, and after 34 weeks it is uncommon.

Separate from all this are the very rare inherited faults in the surfactant proteins themselves. Here severe breathing trouble appears in a baby born at term, does not respond to the usual treatment and calls for genetic testing. It is thought of when the picture does not fit the gestational age, or when a family has already had a baby like this.

Who it affects

The main factor is prematurity, but not the only one. The chance is higher if:

• the mother has diabetes, including diabetes found during pregnancy: high blood sugar slows surfactant maturation, and such a baby can be affected even when born close to term;
• the birth was by caesarean section without labour beforehand: labour itself triggers the release of surfactant and the clearing of fluid from the lungs;
• the baby was short of oxygen during birth, or became very cold in the first minutes;
• it is the second of twins;
• a baby with severe breathing trouble has already been born into the family.

Boys are affected somewhat more often than girls.

What laboured breathing looks like in a newborn

The signs appear in the first minutes or hours after birth and build up over two or three days; then, as the baby's own surfactant starts to come through, things begin to improve. It looks like this:

• fast, shallow breathing, more than sixty breaths a minute;
• a grunt on breathing out: this is the baby generating a little pressure for himself;
• the nostrils flare with each breath;
• the spaces between the ribs and the dip below the breastbone pull inwards;
• the lips, tongue and skin take on a blue tinge;
• the baby is listless, sucks poorly and pauses in breathing.

Almost always this happens on the maternity unit, where help starts at once. But if the birth took place outside hospital, or the baby has already gone home, it falls to the family to act. Call an ambulance (in Spain, Italy, Portugal, Poland and Ukraine the single number is 112) if a newborn is breathing fast and with effort, grunting on breathing out, pulling in the spaces between the ribs, turning blue around the lips or tongue, if he has stopped sucking, has gone floppy, or is pausing in his breathing. Waiting and watching is not an option here: a baby's reserves run out fast.

What can be done before the birth

If a preterm birth is expected or can no longer be stopped, part of the work is done in advance — and this is the single most effective thing there is in the whole subject.

Steroids for the mother. A course of two injections a day apart speeds up the maturing of the baby's lungs and clearly reduces both how often the syndrome occurs and how severe it is. It is given when preterm birth threatens before 34 weeks, and sometimes later too; the obstetrician decides.

Magnesium sulphate. In very early births it is given to the mother to protect the baby's brain: it lowers the risk of cerebral palsy. After prolonged or repeated use the newborn's bones are additionally checked, a rare but recognised consequence.

Medicines that delay labour are not given for the delay itself, but so that the steroid has time to work and so that the mother can be moved to a hospital with a neonatal unit. Being born in such a unit is on its own a factor in a good outcome: the baby will not have to be transported anywhere in those first hours.

The first hours: how the baby is helped

The idea behind the treatment is simple — take over part of the work of breathing until the lungs can manage on their own.

• Warmth. The baby is protected from cooling straight away: getting cold sharply worsens both breathing and metabolism.
• Continuous positive airway pressure through nasal prongs or a mask. This is the mainstay of support: a steady flow of air keeps the air sacs from collapsing while the baby breathes for himself. It is started before a ventilator, because it does less damage to immature lung tissue.
• Artificial surfactant, given straight into the airway through a fine tube or catheter. The earlier it is given, the better the result; often the baby goes straight back onto pressure support afterwards without being put on a ventilator at all.
• Mechanical ventilation, if pressure support is not enough.
• Oxygen, carefully controlled. Only as much as is needed: too much harms a preterm baby, damaging the retina and the lungs.
• Fluids and feeding through a vein until the baby can suck, and antibiotics until infection has been ruled out.

Some babies need support for a few days; very preterm babies for weeks or months. Home usually comes at around the time the baby was originally due.

How it is told apart from other causes

Difficult breathing in the first day of life is not only caused by lack of surfactant, and different causes need different treatment. So the diagnosis is not made by eye.

• A chest X-ray is the key test. Here the lungs look evenly hazy, as though dusted with fine sand, their volume is reduced, and the bronchi stand out against that background. The same film shows a pneumothorax, congenital pneumonia or a diaphragmatic hernia.
• Blood gases — how much oxygen and carbon dioxide are in the blood. They show whether the baby is coping and guide the settings of the support.
• Pulse oximetry — a sensor on the hand or foot measuring oxygen saturation continuously.
• Blood tests and cultures. Congenital pneumonia and blood infection in the first day look exactly the same as this syndrome and cannot be told apart without tests. That is why antibiotics are often started immediately and stopped once infection is excluded.
• An ultrasound scan of the heart, which rules out a congenital heart defect and shows a patent ductus arteriosus.

A separate condition is transient tachypnoea of the newborn, or wet lung: in a baby born nearer to term the fluid clears from the lungs more slowly than usual. Breathing is fast, but it settles within a day or two and no surfactant is needed.

What can go wrong

Most babies with this syndrome do well. But prematurity and the breathing support itself bring their own complications, and it helps parents to know what is meant when the doctor names them.

• Air leak. Air escapes from the lung into the chest cavity — a pneumothorax. The deterioration is sudden: oxygen saturation drops and the breath sounds fade on one side. The air is let out through a tube.
• Patent ductus arteriosus. The vessel that in the fetus joins the aorta to the pulmonary artery often fails to close on time in a preterm baby. The signs are a heart murmur, a rising need for oxygen and puffiness. It is treated with medicines and, less often, with surgery.
• Bleeding. Into the lungs it shows as bright frothy fluid appearing suddenly in the breathing tube. Into the ventricles of the brain it happens mostly in the first days and usually without any outward sign, which is why preterm babies have a routine head ultrasound.
• Bronchopulmonary dysplasia — scarring of immature lung tissue after prolonged ventilation and oxygen. The baby stays oxygen-dependent for longer, breathes fast and tires while feeding. The lungs do mature in time, but a tendency to severe chest infections lasts for years.
• Retinopathy of prematurity and hearing loss. This is exactly why eyes and hearing are checked routinely rather than only when something is noticed.

Going home, and what follows

A baby is ready for discharge when he breathes unaided, holds his temperature and takes his feeds. At home the effort goes into two things: keeping respiratory infections away and not missing a delay in development.

Nobody smokes in the house — not in the rooms, not on the balcony, not in the clothes they smoked in. For the first months it is worth avoiding crowded places and visitors with colds, especially in the respiratory virus season; babies at high risk are offered protection against respiratory syncytial virus. Vaccinations follow the national schedule, counted from the actual date of birth rather than the due date: a preterm baby needs them even more than others.

After that the baby is seen regularly: hearing, vision, weight gain, movement and speech. For the first two years age is counted with an allowance for prematurity — a baby born two months early does at six months roughly what a term baby does at four, and that is not a delay.

Online consultation with a doctor

While the baby is on the unit, a remote appointment helps in making sense of what is happening: what the words on the ward round mean, what surfactant is for and why oxygen is given so sparingly, what an open duct implies, what to expect over the coming days. Parents of a preterm baby often need that more than any advice.

After discharge, online is a convenient way to go through the discharge summary and the follow-up plan, to talk about vaccinations, feeding and weight gain, about outings and visitors, and about worries such as "is it all right that he still isn't sitting?". But breathing is not assessed through a screen: the rate, the recession and the colour of the skin are looked at in person. If the baby is struggling to breathe, grunting, turning blue or going floppy — call an ambulance.

This material is for information only and does not replace medical advice.