Posts Tagged ‘surfactant’

Respiratory distress syndrome (RDS)

Friday, October 29th, 2010

On average, a developing baby’s lungs are considered to be mature and fully functional around 35 to 36 weeks after conception.  For babies born before that, breathing can be a serious challenge.  Respiratory distress syndrome (RDS) is the most common illness in the NICU.  RDS can be mild or quite severe, but the good news is that 99% of babies with RDS survive.  The babies who don’t survive usually are the youngest, smallest babies born before 26 weeks of gestation.

Surfactant is a foamy substance that lines the lungs in mature babies and keeps them from collapsing, making breathing in and out easier. Premature babies lack surfactant and their lungs collapse between breaths.  This makes inhaling air and exhaling carbon dioxide very difficult.  The energy it takes to expand and contract the lungs can be exhausting and overwhelming for these tiny babies.

Research has shown us that the earlier a baby is born the less surfactant is likely to exist in the lungs and the more likely it is for him to develop RDS.  Boys are more likely to get RDS than girls because their lungs mature more slowly. Preemies with mothers who have diabetes  or with Rh blood-type incompatibilities are at greater risk for RDS because their lungs are slower to produce surfactant.  Babies with mothers who have severe preeclampsia are more vulnerable to RDS because their normal lung development is disrupted. Babies born via cesarean delivery and without labor are at increased risk for RDS.  This is because labor produces hormones that promote lung maturation and uterine contractions may help squeeze excess fluid from a baby’s lungs, making breathing easier.

Most babies who will get RDS show symptoms within a few hours of birth.  RDS usually gets worse for a couple of days and then improves as the baby starts to produce more surfactant.  Treatment includes giving a dose or two of man-made surfactant and providing breathing assistance with oxygen, C-PAP or mechanical ventilation, depending on each baby’s needs.

While the survival rate is extremely high, severe RDS may lead to longer-term health problems.  Mechanical ventilation can be life-saving, but it is harsh. Chronic lung disease, also known as bronchopulomonary dysplasia (BPD), comes as a result of inflammation and scaring of the lungs that may result from ventilation.  Children with severe RDS also have an increased likelihood of asthma.

Meconium aspiration

Tuesday, September 21st, 2010

Meconium is the stuff that first poops are made of. It’s greenish-black, sticky and tar-like, but may be treated as gold because it shows that the baby’s intestines are working.

Sometimes the passing of the first stool happens while the baby is still in Mom’s uterus or during delivery.  Meconium aspiration happens when a newborn inhales (or aspirates) a mixture of meconium and amniotic fluid.  The inhaled meconium can partially or completely block the baby’s airways, making it difficult to breathe and causing meconium aspiration syndrome, or MAS.

If that happens, the doctor will order a number of tests to see how affected a baby might be.  The primary focus is to clear the airway as much as possible to decrease the amount of meconium that is aspirated. This is done by inserting a plastic tube into the baby’s windpipe through the mouth or nose and applying suction as the tube is slowly removed. This allows for suction of both the upper and lower airways. The doctor will continue trying to clear the airway until there’s no meconium in the suctioned fluids.

MAS can affect the baby’s breathing in a number of ways including irritation to the lung tissue, airway obstruction by a meconium plug, infection, and the destruction of surfactant by the meconium (read our previous post on surfactant.)  The severity of MAS depends on the amount of meconium the baby inhales and, generally, the more meconium a baby inhales, the more serious the condition.

Babies with MAS may be sent to a special care nursery or a NICU to be carefully monitored for the next few days. Most babies with MAS improve within a few days or weeks and usually there is not severe permanent lung damage.  These babies, however, may be at a higher risk of having reactive airway disease (lungs that are more sensitive and can possibly lead to an asthmatic condition).  Severe cases may necessitate the baby be given mechanical ventilation, which can increase the risk for bronchopulmonary dysplasia, a lung condition that can be treated with medication or oxygen.  Rarely, MAS can lead to a collapsed lung or pneumonia.

If not at the hospital when her water breaks, it’s important for a pregnant woman to tell her doctor immediately if meconium is present in the amniotic fluid, or if the fluid has dark green stains or streaks. Doctors may use a fetal monitor during labor to monitor the baby’s heart rate for any signs of fetal distress. In some cases they may recommend amnioinfusion, adding saline to the amniotic fluid to wash meconium out of the amniotic sac before the baby has a chance to inhale it at birth.

Although MAS is a frightening complication for parents to face during the birth of their child, the majority of cases are not severe.  Did any of you face this problem?

In the NICU – what is surfactant?

Thursday, July 29th, 2010

The DiscoveryHealth NICU series (Thursdays at 10 PM ET/PT) is provoking lots of conversation and questions.  We were recently asked about surfactant and how it helps a premature baby’s lungs.

“Surfactant” is a condensed form of the term “surface-active agent,” meaning something that reduces the surface tension of liquids. So what does that really mean? Example:  Detergents are surfactants – their lowering of the natural surface tension of water is what keeps bubbles from collapsing, and lets dishwater foam.  Mature lungs are foamy organs, largely composed of tiny, bubble-like air sacs that are prevented from collapsing by lung surfactant.  This complex mixture of fatty substances and specialized proteins is produced in the lungs, starting many weeks before birth.

Premature babies often lack lung surfactant.  The more prematurely a baby is born, the less likely it is to be producing enough surfactant to enable normal lung function.  Immature lungs resist inflation and collapse after each exhale.  The effort of breathing under these circumstances – called “respiratory distress syndrome,” or RDS – can exhaust a very small, premature newborn and lead to severe complications and even death.  Survivors of RDS may have brain damage due, in part, to being unable to get enough air.  In recent decades, respiratory treatments have contributed to the improved survival rates for premature babies, but the lungs of some babies have been injured in the process.

Lung surfactant was identified in the 1950s. During the 1980s, many research groups around the world studied surfactant from human amniotic fluid and synthetic varieties.  Such studies showed the safety and effectiveness of both rescue treatment (given to babies already developing RDS) and preventive treatment (given to very premature infants before they show signs of RDS.)

The March of Dimes is pleased to have supported early research on lung surfactant for premature infants.  Widespread use of surfactant has contributed to a significant drop in deaths from RDS and a drop in the U.S. infant mortality rates. In the past decade, the March of Dimes has invested over $2.6 million in research involving lung surfactant.