The study involves “amniotic exchange,” a procedure new to the U.S., in which surgeons remove caustic amniotic fluid from the uterus and replace it with sterile saline or lactated ringers solution. Introduced in Paris, France, the technique is the first to alter the makeup of amniotic fluid to treat fetal disorders.
Dr. Joseph Bruner, associate professor of obstetrics and gynecology and director of fetal diagnosis and therapy at Vanderbilt University Medical Center will perform the first amniotic exchange in the U.S. on July 5; two other study enrollees have been randomized at Vanderbilt as controls. “There’s no doubt that as soon as the results of the study are published they will change the management of gastroschisis overnight,” Bruner said.
Gastroschisis, diagnosed with ultrasound, occurs when a hole forms in a fetus’ abdominal wall. Part of the intestines protrude through the hole and spill into the uterus. As pregnancy advances, the amniotic fluid becomes toxic and harms parts of the fetus not designed to be exposed to it, such as internal organs. The intestines thicken, entangle and inflame. “By 30 weeks, this fluid resembles liquid from a septic tank,” Bruner said.
Standard therapy calls for these fetuses to be delivered early, often by cesarean section. But complications include longer than average times in costly neonatal intensive care units, longer times before their first feedings (requiring tube feeding) and between subsequent feedings, and longer waits until surgical correction.
In a pilot trial of 20 patients in Paris at the Maternity de l’Hopital Robert-Debre, simply removing the toxic amniotic fluid improved all outcomes 30% to 50 %. The babies were born at or near term with healthier intestines, had shorter intervals to surgery, shorter times to full feedings and between feedings and shorter intensive care unit and overall hospital stays. No babies required tube feeding.
A risk of amniotic exchange is induced early delivery. But, Bruner said, the same risk is inherent with the disorder. The complication was absent in the France study.
Bruner expects more than a dozen medical centers throughout the United States to eventually join Vanderbilt in the study. Eligible participants will have fetuses with gastroschisis and no other complications. All enrollees will be randomized and pediatric surgeons assigned to follow the cases will be blind to the enrollment.
In 1997, Bruner became a pioneer of fetal surgery when he and neurosurgeon partner Dr. Noel Tulipan began repairing in utero fetuses with spina bifida.