Definition: When the newborn or fetus inhales
meconium (first stool) into the lower
respiratory tract.
1. What caused this condition?
The baby had a bowel movement while still inside the mother’s
uterus. Meconium is the name for the first stools that a baby passes.
The meconium gets into the fluid surrounding the baby and can be
swallowed into the lungs or breathing passageways prior to or at the
time of birth. Babies that are under stress or go beyond their expected
due date have a higher incidence of passing meconium while still in
the uterus. Generally, meconium aspiration is seen in babies that are
not premature.
2. Is this condition dangerous, and what kind of
damage can it cause?
If the meconium gets into the airways leading to the lungs, it causes a
blockage of the passageways. This stops or impedes the flow of air into and out of portions of the lungs. This can lead to low oxygen levels or
a buildup of carbon dioxide.
If significant, this disruption in the functioning of the lungs can
lead to a continued high blood pressure in the blood vessels leading to
the lungs. When this occurs, there is further inability of the lungs to
get oxygen into the bloodstream and to remove carbon dioxide due to
blood bypassing the lungs.
Another common complication of meconium aspiration is the
development of a hole in the lung(s). This is called a pneumothorax.
Air escapes from the lung into the chest cavity and is trapped between
the chest wall and lung. As the air builds up, it compresses the lung
and again disrupts normal lung function.
3. What tests are needed to further define the condition?
The presence of meconium is noted when the water is broken either
naturally or by the obstetrician. The fluid will have a greenish
discoloration. The thickness and degree of discoloration indicates
the amount of meconium present. After the baby is born chest X rays
will confirm the findings of meconium aspiration if present. A
sample of blood called a blood gas along with oxygen-level monitoring (pulse oximeter) will show low oxygen levels and disturbances
in lung functioning.
4. What is the treatment?
Prevention is the main treatment. If meconium stained fluid is
noted, the obstetrician may infuse sterile salt water into the uterus
to dilute the meconium. At the time of delivery, the obstetrician will
attempt to clean out the nose and mouth prior to the delivery of the
rest of the baby. The baby may then have a breathing tube passed into the trachea, the main passage to the lungs, and suction applied
while it is removed.
If the baby has further or continued problems, then additional oxygen
and/or a breathing machine may be needed. If a breathing tube is
needed, the instillation of a medication called surfactant may be given
through it to help break up the meconium and improve the function of
the lungs. If the baby has significant breathing concerns, a ventilator
called an oscillator may be used.
If the baby develops a pneumothorax, or hole in the lung(s), a
drainage tube may be needed. This drainage tube is called a chest
tube, and it is placed between the ribs on the side of the air leak to
prevent the lung from collapsing.
5. What side effects can occur from the treatment?
The most common early side effect is a hole in the lung(s) from air
being trapped by the meconium or from the degree of ventilator
support required to get acceptable oxygen and carbon dioxide levels.
It is treated as mentioned above.
The lungs can be injured from being on the ventilator. They may
develop an inflammatory reaction to the irritation of the meconium
and being on the ventilator and high oxygen concentrations. If this
occurs, it may delay coming off of the ventilator and additional
oxygen. This inflammatory response can occasionally lead to the baby
having feeding problems due to increased work of breathing and
needing extra oxygen at the time of discharge.
Infrequently, a baby may have severe meconium aspiration along
with severe elevations in the blood pressure in the blood vessels
leading to the lungs. This may require treatment with a heart-lung
bypass (ECMO).
6. How long will it take for my baby to show
improvement?
Most babies get better in seven to ten days. A baby with severe meconium aspiration may require a longer hospital stay, potentially up to a
month, to be well enough to be discharged.
7. What complications can develop?
The more frequent complications are the same as the side effects from
being treated. Holes in the lung (pneumothoraces) or the failure of
the blood pressure to lower in the lungs after birth (pulmonary hyper-
tension) may be present and complicate the meconium aspiration.
Occasionally, babies may have some inflammation in their lungs that
delays their improvement.
8. Can pneumonia develop?
Pneumonia caused by bacteria is not associated with the meconium
aspiration itself. Infection may occur in any patient that has a
breathing tube in place and receives ventilatory support for a period
of time, especially longer than fourteen days.
9. Will this condition weaken my baby’s lungs for the
future?
Both the presence of meconium and being on a breathing machine
with exposure to high concentrations of oxygen can cause an inflammatory response in the lungs. In some cases this can lead to delayed
recovery and some lung abnormalities for the first several months of
life. Most babies with mild-to-moderate meconium aspiration will not
have any long-lasting lung problems.
10. After discharge from the hospital, what kind of
follow-up will be needed?
In most cases, your child’s pediatrician will be all that is necessary. In
severe cases of meconium aspiration, the baby may be at more risk for
developmental delays and a developmental specialist may be required.
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