By Clinton Colmenares
July 13, 2001
At 1:30 p.m. on Friday, July 7, a middle
Tennessee woman lay in Labor and Delivery room 10, her belly slightly
swollen with her first expected child. Her husband gently stroked
her head as her doctor passed an ultrasound wand over her womb.
He was preparing to begin a new research procedure that, hopefully,
would improve the fetus' health even before birth. With another
12 weeks to term, the couple's baby was about to receive a first
bath, of sorts. The fetus had been diagnosed with gastroschisis,
a developmental abnormality that caused the intestines to poke through
a weakness in the abdominal wall and into the mother's uterus, where
the amniotic fluid was becoming increasingly concentrated with urine
and toxic to the delicate internal organs turned outward.
To halt the damage, Dr. Joseph Bruner,
associate professor of obstetrics and gynecology and director of
fetal diagnosis and therapy, inserted a flexible needle into the
mother's womb, guiding it by ultrasound, while Dr. Erin Harley,
a resident, drew out all the amniotic fluid with a large syringe
and replaced it with sterile saline solution.
Not only was this a first for the fetus,
the "amniotic exchange" was the first performed in the United States
for gastroschisis, and one of a handful performed in the world.
In June, Bruner began a randomized study of the procedure. Two other
couples have been randomized into standard therapy - delivering
the babies early and surgically mending the damaged intestines when
time allowed. "We're just glad to be a part of this," said the young
dad, naturally a little anxious. "We hope that, regardless of our
outcome, this improves the treatment for everyone." The couple's
names were not released to protect their anonymity. For the study,
pediatric surgeon, Dr. Robert Cywes, assistant professor of surgery,
will follow the enrollees and will not know who received amniotic
exchange or standard therapy.
Bruner called the procedure, which
includes a total of four amniotic exchanges over eight weeks, "deceptively
simple." It can be performed in less than an hour, in most labor-and-delivery
"This is a whole new area never addressed
before - altering the amniotic constitution to protect vulnerable
fetal body parts from amniotic fluid to treat fetal disorders,"
Gastroschisis is not a life-threatening
disorder, Bruner said. But it occurs in one in 4,000 live births
in the United States. Fourteen children born at Vanderbilt in the
year 2000 had the disorder.
Previous Vanderbilt research has shown
that at about 30 weeks gestation the amniotic fluid becomes increasingly
toxic and harmful to body parts not meant to be exposed to it. With
gastroschisis, the intestines "become inflamed, almost as if they
had been burned," Cywes said. They shorten, sometimes by as much
as one-third, and can form atresias, leaving gaps in the bowels.
After birth, the baby requires a "tent"
over the exposed bowel to protect it until it heals enough to allow
surgery. These babies often have delays in first feedings, delays
in their first full feedings, longer times in a neonatal intensive
care unit, longer waits to surgical intervention and longer hospital
In Paris, France, where the procedure
was developed, researchers believe simply exchanging the toxic fluid
for sterile liquid prevents damage. At Maternity de l'Hopital Robert-Debre,
20 patients received the amniotic exchange with 30 percent to 50
percent improvements to all the complications, and none of the infants
required tube feeding, said Bruner, who learned of the technique
from its first investigator during a conference last year.
There are two points of debate: that
with standard therapy early delivery of the fetus will prevent injury
to the bowel, and that cesarean sections help protect the bowel.
The study, Bruner said, will address these concerns by seeing the
babies to term and delivering them vaginally, when possible. There
is a risk of premature delivery. But, Bruner said, the risk also
exists with the disorder, regardless of intervention.
"There's no doubt in my mind that once
we publish the results of this study the management of gastroschisis
will change overnight," Bruner said. He hopes to enroll 20 patients
this year, and expects as many as a dozen other U.S. medical centers
and several more across the globe to join the study. The study is
currently funded by a VUMC Discovery Grant; NIH funding is speculated
for the future.
Cywes agrees that the procedure soon
will be widely accepted, and said that it's important for it to
begin with data from a randomized, controlled study. "People are
going to be doing this. We want to make sure they're doing it for
the right reason," he said.
Patients enrolled in the study receive
a series of counseling sessions to explain fetal medicine, including
talks with social workers, ethicists, financial coordinators and
the surgeons. The babies will be followed after birth through the
NICU and corrective surgery. There will still be questions to answer
in subsequent research, Bruner said, including patient selection
and how many exchanges are optimal.
After about 40 minutes, Bruner and
Harley had drawn out 280 ccs of fluid, replaced it with 300 of saline,
then removed another 300 and finally bathed the fetus in an equal
amount of sterile solution. After the first drought the fluid was
a dense, dull yellow; after the second it was almost clear. Samples
were collected for analysis here and in Paris to determine what
irritates the bowel.
With the procedure finished, both expectant
parents smiled and breathed easier, glad there was an option that
might help their baby, and possibly many others.