Parents with a premature baby in the neonatal intensive care unit don't need one more thing to worry about. But researchers say that plasticizers used in medical equipment may pose unique risks to very small babies.
The chemical DEHP is used to make catheters, endotracheal tubes and other medical equipment soft and pliable. It and other phthalates have been found to affect growth and development in animal studies. But the doctors at Johns Hopkins Bloomberg School of Public Health who conducted this review say they're more concerned about its immediate health effects on critically ill infants.
"I had wondered for years how much they might be getting and what the health effects might be," says Dr. Eric Mallow, a neonatologist and public health researcher at Hopkins. "We take the NICU totally for granted, and we don't necessarily think about the things right in front of us."
Mallow and his colleagues reviewed published data on DEHP's known toxicity, and how much it leaches out of polyvinyl chloride medical devices. They then calculated how much a very small preemie, about 2 pounds, would be exposed to.
They determined that a critically ill preemie hooked up to multiple tubes and devices containing DEHP could be exposed to 16 milligrams per kilogram of body weight a day of the chemical, which is 160,000 times higher than desired to avoid liver damage. The study was published Thursday in the Journal of Perinatology.
Most studies of DEHP have focused on its effects as an endocrine disruptor; it's been shown to affect development of male sex organs in mice. But Mallow thinks it might affect preemies' health more immediately.
"DEHP and other phthalates are proinflammatory, and most of the injuries that preemies get are inflammatory in nature," Mallow told Shots. There's no proof that DEHP is causing or contributing to those injuries, he notes. No research has been done on that.
Parents and doctors shouldn't avoid needed medical procedures because medical equipment may contain DEHP, the Food and Drug Administration said in a 2002 public health notification on the issue.
Some hospitals have moved to use equipment without DEHP; in 2013, the Kaiser Permanente system pledged to reduce or eliminate use of IV lines and other equipment with DEHP.
"But the great majority of units have not made that switch," Mallow says.
Parents and doctors shouldn't avoid needed medical procedures because medical equipment may contain DEHP, the Food and Drug Administration said in a 2002 public health notification on the issue. It has recommended that devices without DEHP be used for high-risk procedures, and that exposure be minimized, for instance, by using "the freshest, coldest blood products available" so they absorb less DEHP.
"The devices and plastics were first introduced in adult intensive care," Mallow says. When the devices were adapted for use in children, "the material didn't change, and didn't take into consideration the particular vulnerability of the population. But when you get down to a one-pound baby who has tenuous organ function and is very immature, the materials used to care for that baby should be given consideration."
He realizes that his study could worry parents already dealing with a sick child, Mallow says: "I realize this could be a side effect of this paper." But he hopes the information in this study will be used to make NICUs safer for all babies.