What is RDS?
If a baby is born before his lungs have matured, he will
develop respiratory distress syndrome (RDS). A baby with
RDS tries to cry and breathe at birth, but within minutes to
hours he starts working hard to breathe because his lungs
tend to collapse with each breath.
A baby with RDS:
breathes faster than 60 breaths a minute
makes a grunting sound when he breathes out
pulls in the chest wall and the spaces between the ribs
when he tries to breathe (these movements during
breathing are called retractions)
has flaring of the nostrils
has a bluish color around the lips, which means that he
needs more oxygen.
Two other possible causes of breathing problems in babies
are infection in the lungs (pneumonia) and extra fluid in
the lungs.
What causes RDS?
Before birth a baby does not use his lungs because the
placenta delivers oxygen from the mother to the baby's
bloodstream. Once the baby is born, the baby's lungs fill
with air and begin delivering oxygen to the blood. To
prepare the lungs to work properly after birth, a baby
produces a substance called surfactant.
Surfactant is a material that lines the air sacs of the
lungs and helps keep the lungs open when breathing out.
Babies usually start making surfactant sometime between the
30th and 36th weeks of the pregnancy. Nearly all babies
have made surfactant by the 35th week of pregnancy. Certain
events, such as the mother's water breaking early or preterm
labor, may cause a baby to start making surfactant early.
Without surfactant, the lungs tend to collapse with each
breath. A lack of surfactant causes RDS.
How is it diagnosed?
Certain laboratory tests are done to help determine the
cause of the breathing problems. These tests include:
Blood culture: Because the cause of a breathing problem
may not be known right away, all babies are treated for
the possibility of infection with antibiotics. Before
starting the antibiotics, a sample of the baby's blood is
tested for infection. The test is called a blood
culture. If the baby does not have an infection, the
test will be negative and the antibiotics will be stopped
in 3 days. Antibiotics are safe and do not cause any
long-term problems. Your health care provider will
probably take the blood sample from a vein or artery.
Blood gas test: Blood gas tests show how much oxygen is
in the bloodstream. This information helps your doctor
know how much oxygen the baby needs. It also tells how hard
the baby is working to breathe and whether he needs help to
keep breathing.
Chest x-ray: X-rays for babies use very little radiation
and do not cause the baby any problems later in life.
What is the treatment?
Many babies develop RDS. Usually the babies who have RDS
are more than 6 weeks premature, but occasionally more
mature babies have RDS. There are many effective treatments
for babies with RDS, and most infants recover completely
within the first weeks of life.
The special care nursery (SCN)
A baby who has breathing difficulties is placed on a
warming bed in the special care nursery (SCN). He is
attached to a monitor that continuously measures his
heart rate and respiratory (breathing) rate. This
monitor is called a cardiorespiratory monitor. The baby
is also attached to a monitor that records the amount of
oxygen in his skin. It is called a pulse oximeter.
IV fluids
A baby with RDS breathes fast and uses all of his energy
to breathe. He does not have any energy left for eating
and cannot coordinate sucking with the fast breathing
rate. An intravenous (IV) line is inserted into the
veins of the baby's hands, feet, or scalp. The IV
provides fluid to prevent dehydration and gives the baby
sugar for energy. The baby will be able to take milk
after the lungs have improved.
Oxygen
A baby with RDS needs extra oxygen to keep the level of
oxygen in his blood in the normal range. If tests show
that a baby needs extra oxygen, he is placed in a plastic
hood into which extra oxygen is blown. The level of
oxygen a baby breathes is called FiO2. The level of
oxygen in the blood is called pO2.
Umbilical artery catheter
If a baby needs more than 40 percent oxygen or a
ventilator to breathe, the blood gases are checked
frequently. So the baby does not have to be stuck with a
needle each time a sample of blood is needed, an IV line
may be inserted into an artery. The IV is often placed
in the artery in the umbilical cord and passed into the
aorta, the largest artery in the body. This umbilical
artery catheter allows blood to be taken painlessly from
the baby. The catheter can also be used to give fluids
and medications to the baby. Arteries in the hands and
feet may also be used for the IV.
Assisting the baby's breathing
If the work of breathing becomes too difficult for the
baby, he will begin to tire. There are two ways to help
his breathing: nasal CPAP and a ventilator.
Nasal CPAP: Nasal CPAP is a device that blows oxygen
under pressure in through the nose. It helps inflate the
lungs. A strap placed around the baby's head holds the
CPAP prongs in the nose. The baby does all the breathing
but the CPAP delivers oxygen at a pressure that keeps the
lungs inflated. Nasal CPAP is used for the bigger and
stronger babies or babies who have mild disease and need
just a little help.
Ventilator: When a baby gets too tired to breathe
effectively, a ventilator may be used to give the baby
extra breaths. A tube is placed through the baby's mouth
and into the windpipe (trachea). The tube is kept in
place with tape across the baby's upper lip. The
ventilator blows oxygen under pressure through the tube
and into the baby's lungs. The baby breathes on his own,
but the ventilator gives extra breaths.
Babies usually get used to the ventilator and actually
feel more comfortable because they don't have to work so
hard to breathe. Occasionally a baby may be irritated by
the ventilator. If this happens the baby may be given a
mild sedative to help him relax and sleep.
Artificial surfactant
Babies who need a ventilator may be given 2 to 4 doses of
artificial surfactant during their first 24 to 48 hours
of life. If artificial surfactant is given, not as much
oxygen or pressure on the ventilator will have to be
used, and the baby will get better faster. The baby will
still need the ventilator for about 3 days and then will
begin to get better as his lungs make his own surfactant.
How long does recovery take?
A baby with RDS is sick for about 3 days. In the first
3 days his need for oxygen will increase or stay the same.
When the baby starts needing less oxygen, it is a sign that
the baby is getting better. If your baby is on a
ventilator, the amount of oxygen and breaths he is given
will be reduced until he can finally breathe on his own. At
this time the breathing tube can be removed.
When the baby is able to breathe easily at a normal rate and
does not need extra oxygen, he can begin feedings. If the
baby is strong and mature enough to suck, he can begin to
breast-feed or bottle-feed. However, often a baby is weak
because his lungs are still recovering. A weak baby can be
fed by passing a tube through his mouth and into his
stomach. Milk is dripped through the tube into the baby's
stomach. This is called gavage feeding. This way the baby
can be fed without using a lot of energy to suck. Soon he
will be able to breast- or bottle-feed vigorously.
All babies can go 4 or more days on IV fluids without eating
and be perfectly fine. Don't worry if your baby can't eat
at first and loses weight. Once he is well, he will make up
for lost time. Even a healthy baby who eats immediately
after birth loses weight in the first week of life.
Are there complications?
Most babies recover completely from RDS with no short-or
long-term problems. The most common complication occurring
shortly after birth is a pneumothorax. Long-term problems,
such as chronic lung problems or neurologic problems (brain
damage), are usually related to how premature the baby is
rather than to the RDS.
Pneumothorax
Sometimes the air sacs of a baby's lungs tear. The air
that should be inside the air sacs escapes outside the
lungs but remains inside the chest. The accumulated air
then presses on the lung and makes it even more difficult
for the baby to breathe. This is called an air leak, or
pneumothorax. A pneumothorax may occur at any time with
no apparent cause, or it may happen when the baby is
receiving oxygen under pressure (on CPAP or a
ventilator).
A small pneumothorax does not require treatment. A
larger one is treated by drawing the air out through a
needle. For the largest or most persistent air leaks, a
tube is inserted into the chest and the air is drained
out continuously. Over time (hours to days), the air
sacs heal themselves and the tube can be removed.
Chronic lung disease
Babies who have unusually severe lung disease or are very
premature may require a lot of oxygen and pressure from
the ventilator to survive. This can scar the lungs.
Some of these babies may need to be on the ventilator for
several weeks and may need oxygen for several months.
These babies may be given diuretics to get rid of extra
water in the lungs.
Most babies outgrow these problems in the first few
months. They grow new lung tissue, which replaces the
scarred lung tissue. However, during the first few years
of life they may have more bouts of wheezing and may get
pneumonia when they have upper respiratory infections
(colds). These problems will occur less often as the
children grow older.
Virtually all babies who have respiratory distress syndrome
grow up to be healthy, normal children. RDS does not cause
brain damage or long-term developmental problems.
Can RDS be prevented?
If the doctor knows that the baby is going to be premature,
drugs can be given to the mother to help the baby start
producing surfactant before birth. The most frequently used
drug is betamethasone.
By testing the amniotic fluid, doctor's can check if a baby
has made surfactant. Amniotic fluid is collected by doing a
procedure called an amniocentesis. The fluid can also be
sampled right after the mother's water breaks. If the baby
has not yet made surfactant, the mother may be given
betamethasone and may also be given other drugs to try to stop
labor and delay the birth.
