Pulmonary
Atresia (PA)
Pulmonary
atresia (PA) is a complicated congenital (present
at birth) defect that occurs due to abnormal development
of the fetal heart during the first 8 weeks of
pregnancy.
The
pulmonary valve is found between the right ventricle
and the pulmonary artery. It has three leaflets
that function like a one-way door, allowing blood
to flow forward into the pulmonary artery, but
not backward into the right ventricle.
With
pulmonary atresia, problems with valve development
prevent the leaflets from opening, therefore,
blood cannot flow forward from the right ventricle
to the lungs. Before birth, while the fetus is
developing, this actually is not a threat to life,
because the placenta provides oxygen for the baby
and the lungs are not functional. Blood entering
the right side of the fetal heart passes through
an opening called the foramen ovale that allows
oxygen-rich (red) blood to pass through to the
left side of the heart and proceed to the body.
In some
cases, there may be a second opening, this time
in the ventricular wall, that allows blood in
the right ventricle a way out. This opening is
called a ventricular septal defect (VSD). If there
is no VSD, the right ventricle receives little
blood flow before birth and does not develop fully.
After
birth, the placenta no longer provides oxygen
for the newborn - the lungs must provide it. However,
with no pulmonary valve opening present, blood
must find another route to reach the lungs and
receive oxygen.
The
foramen ovale normally shuts at birth, but may
stay open in this situation, allowing oxygen-poor
(blue) blood to pass from the right atrium to
the left atrium. From there, it goes to the left
ventricle, out the aorta, to the body. This situation
cannot support life, since oxygen-poor (blue)
blood cannot meet the body's demands. Newborns
also have a connection between the aorta and the
pulmonary artery, called the ductus arteriosus,
that allows some of the oxygen-poor (blue) blood
to pass into the lungs. Unfortunately, this ductus
arteriosus normally closes within a few hours
or days after birth.
Because
of the low amount of oxygen provided to the body,
pulmonary atresia is a heart problem that is labeled
"blue-baby syndrome."
The
problem occurs as the heart is forming during
the first 8 weeks of fetal development.
Some
congenital heart defects may have a genetic link,
either occurring due to a defect in a gene, a
chromosome abnormality, or environmental exposure,
causing heart problems to occur more often in
certain families. Most of the time, this heart
defect occurs sporadically (by chance), with no
clear reason for its development.
Symptoms
will be noted shortly after birth. The obvious
indication of PA is a newborn who becomes cyanotic
(blue) in the transitional first day of life when
the maternal source of oxygen (from the placenta)
is removed. The degree of cyanosis is related
to the presence of other defects that allow blood
to mix, including a patent (open) ductus arteriosus.
The
following are the most common symptoms of pulmonary
atresia. However, each child may experience symptoms
differently. Symptoms may include:
- rapid breathing
- difficulty breathing
- irritability
- lethargy
- pale, cool, or clammy
skin
The
symptoms of pulmonary atresia may resemble other
medical conditions or heart problems. Always consult
your child's physician for a diagnosis.
A pediatric
cardiologist and/or a neonatologist may be involved
in your child's care. A pediatric cardiologist
specializes in the diagnosis and medical management
of congenital heart defects, as well as heart
problems that may develop later in childhood.
A neonatologist specializes in illnesses affecting
newborns, both premature and full-term.
Cyanosis
is a major indication that there is a problem
with your newborn. Your child's physician may
have also heard a heart murmur during a physical
examination. A heart murmur is simply a noise
caused by the turbulence of blood flowing through
the openings that allow the blood to mix.
Other
diagnostic tests are needed to help with the diagnosis,
and may include the following:
- chest x-ray -
a diagnostic test which uses invisible electromagnetic
energy beams to produce images of internal tissues,
bones, and organs onto film.
- electrocardiogram
(ECG or EKG) - a test that records
the electrical activity of the heart, shows
abnormal rhythms (arrhythmias or dysrhythmias),
and detects heart muscle stress.
- echocardiogram (echo)
- a procedure that evaluates the
structure and function of the heart by using
sound waves recorded on an electronic sensor
that produce a moving picture of the heart and
heart valves.
- cardiac catheterization
- a cardiac catheterization is an
invasive procedure that gives very detailed
information about the structures inside the
heart. Under sedation, a small, thin, flexible
tube (catheter) is inserted into a blood vessel
in the groin, and guided to the inside of the
heart. Blood pressure and oxygen measurements
are taken in the four chambers of the heart,
as well as the pulmonary artery and aorta. Contrast
dye is also injected to more clearly visualize
the structures inside the heart.
Specific
treatment for pulmonary atresia will be determined
by your child's physician based on:
- your child's age, overall
health, and medical history
- extent of the disease
- your child's tolerance
for specific medications, procedures, or therapies
- expectations for the
course of the disease
- your opinion or preference
Your
child will most likely be admitted to the intensive
care unit (ICU) or special care nursery once symptoms
are noted. Initially, your child may be placed
on oxygen, and possibly even on a ventilator,
to assist his/her breathing. Intravenous (IV)
medications may be given to help the heart and
lungs function more efficiently.
Other
important aspects of initial treatment include
the following:
- A cardiac catheterization
procedure can be used as a diagnostic procedure,
as well as initial treatment procedure for some
heart defects. A cardiac catheterization procedure
will usually be performed to evaluate the defect(s),
whether the foramen ovale or ductus arteriosus
are still open, and the amount of blood that
is mixing.
- As part of the cardiac
catheterization, a procedure called balloon
atrial septostomy may be performed to improve
mixing of oxygen-rich (red) blood and oxygen-poor
(blue) blood between the right and left atria.
- A special catheter
with a balloon in the tip is used to create
an opening in the atrial septum (wall between
the left and right atria).
- The catheter is
guided through the foramen ovale (a small
opening present in the atrial septum that
closes shortly after birth) and into the
left atrium.
- The balloon is
inflated.
- The catheter is
quickly pulled back through the hole, into
the right atrium, and a hole is created,
allowing blood to mix between the atria.
- An intravenous medication
called prostaglandin E1 is given to keep the
ductus arteriosus from closing.
These
interventions will allow time for your baby to
stabilize.
- surgical repair
Ultimately, surgery is necessary to improve
blood flow to the lungs on a permanent basis.
A series of operations are usually recommended
and are performed in stages, usually starting
shortly after birth. In this series of operations,
blood flow is redirected to the lungs and the
body with various surgical connections. Types
of surgical procedures that may be used include
the Rastelli procedure and the Fontan procedure.
After
surgery, infants will return to the intensive
care unit (ICU) to be closely monitored during
recovery.
While
your child is in the ICU, special equipment will
be used to help him/her recover, and may include
the following:
- ventilator -
a machine that helps your child breathe while
he/she is under anesthesia during the operation.
A small, plastic tube is guided into the windpipe
and attached to the ventilator, which breathes
for your child while he/she is too sleepy to
breathe effectively on his/her own. After a
pulmonary atresia, children will benefit from
remaining on the ventilator overnight or even
longer so they can rest.
- intravenous (IV) catheters
- small, plastic tubes inserted
through the skin into blood vessels to provide
IV fluids and important medicines that help
your child recover from the operation.
- arterial line -
a specialized IV placed in the wrist or other
area of the body where a pulse can be felt,
that measures blood pressure continuously during
surgery and while your child is in the ICU.
- nasogastric (NG) tube
- a small, flexible tube that keeps
the stomach drained of acid and gas bubbles
that may build up during surgery.
- urinary catheter -
a small, flexible tube that allows urine to
drain out of the bladder and accurately measures
how much urine the body makes, which helps determine
how well the heart is functioning. After surgery,
the heart will be a little weaker than it was
before, and, therefore, the body may start to
hold onto fluid, causing swelling and puffiness.
Diuretics may be given to help the kidneys to
remove excess fluid from the body.
- chest tube -
a drainage tube may be inserted to keep the
chest free of blood that would otherwise accumulate
after the incision is closed. Bleeding may occur
for several hours, or even a few days after
surgery.
- heart monitor -
a machine that constantly displays a picture
of your child's heart rhythm, and monitors heart
rate, arterial blood pressure, and other values.
Your
child may need other equipment not mentioned here
to provide support while in the ICU, or afterwards.
The hospital staff will explain all of the necessary
equipment to you.
Your
child will be kept as comfortable as possible
with several different medications; some which
relieve pain, and some which relieve anxiety.
The staff will also be asking for your input as
to how best to soothe and comfort your child.
After
discharged from the ICU, your child will recuperate
on another hospital unit before going home. You
will learn how to care for your child at home
before your child is discharged. Your child may
need to take medications for a while, and these
will be explained to you. The staff will give
you written instructions regarding medications,
activity limitations, and follow-up appointments
before your child is discharged.
Infants
who spent a lot of time on a ventilator, or who
were fairly ill while in the ICU, may have trouble
feeding initially. These babies may have an oral
aversion; they might equate something placed in
the mouth, such as a pacifier or bottle, with
a less pleasant sensation such as being on the
ventilator. Some infants are just tired, and need
to build their strength up before they will be
able to learn to bottle-feed. Strategies used
to help infants with nutrition include the following:
- high-calorie formula
or breast milk
Special nutritional supplements may be added
to formula or pumped breast milk that increase
the number of calories in each ounce, thereby
allowing your baby to drink less and still consume
enough calories to grow properly.
- supplemental tube
feedings
Feedings given through a small, flexible tube
that passes through the nose, down the esophagus,
and into the stomach, that can either supplement
or take the place of bottle feedings. Infants
who can drink part of their bottle, but not
all, may be fed the remainder through the feeding
tube. Infants who are too tired to bottle feed
at all may receive their formula or breast milk
through the feeding tube alone.
Pain
medications, such as acetaminophen or ibuprofen,
may be recommended to keep your child comfortable.
Your child's physician will discuss pain control
before your child is discharged from the hospital.
If any
special treatments are to be given at home, the
nursing staff will ensure that you are able to
provide them, or a home health agency may assist
you.
You
may receive additional instructions from your
child's physicians and the hospital staff.
The
outlook varies from child to child. Follow-up
care at a center offering pediatric congenital
cardiac care should be carried out regularly.
It is not unexpected for multiple re-operations
to be performed to replace conduits or revise
a palliation.
Consult
your child's physician regarding the specific
outlook for your child.
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