PREMATURE INFANTS ARE EXPOSED TO UNSAFE LEVELS OF CHEMICAL IN MEDICAL PRODUCTS USED TO DAVE THEIR LIVES
Hospitalized premature
infants are exposed to unsafe levels of a chemical found in numerous medical
products used to treat them, raising questions about whether critically ill
newborns may be adversely affected by equipment designed to help save their
lives.
The chemical,
di(2-ethylhexyl)phthalate (DEHP), is used to increase flexibility of many
plastic devices. These products, made from polyvinyl chloride (PVC), include most
intravenous tubing, catheters, endotracheal tubes, and fluid and blood product
bags. DEHP doesn't bind chemically to PVC, and is able to leach into fluids and
body tissues in contact with it. New Johns Hopkins Bloomberg School of Public
Health research suggests that critically ill preterm infants may be exposed to
DEHP at levels approximately 4,000 to 160,000 times higher than those believed
to be safe. Infants can receive high exposures to DEHP during weeks to months
of treatment in a hospital's neonatal intensive care unit (NICU).
The results are
reported online Nov. 13 date by the Journal of Perinatology.
"It's
remarkable that the care of sick and developmentally vulnerable preterm infants
depends on an environment composed almost entirely of plastic," says
neonatologist Eric B. Mallow, MD, MPH, a senior research program coordinator at
the Bloomberg School and the study's leader. "The role of these synthetic
materials in the clinical course of our patients remains almost completely
unexplored. PVC is the predominant flexible plastic in most NICUs, and this can
result in considerable DEHP exposures during intensive care."
Mallow and
co-investigator Mary A. Fox, PhD, MPH, an assistant professor in the Department
of Health Policy and Management, reviewed and analyzed previously published
studies of DEHP and its potential risks. Nearly all public attention to the
health effects of phthalates, for both the general population and hospitalized
patients, has focused on their role as endocrine disruptors -- substances that
can interfere with normal hormone function.
However, the
researchers found abundant published evidence that DEHP has a wide range of
non-endocrine toxic effects, and they propose that these could affect the
short- and long-term health of NICU patients. DEHP has been shown repeatedly in
animal studies to increase inflammation, cause liver injury, and interfere with
development of lung, brain, and eye. Clinical studies confirm that some of
these effects occur in NICU patients as well.
"We were
floored by how high the exposures are when you look at all of the devices
together," Fox says. "It's a population that we know is vulnerable to
begin with. They're struggling to survive. And the concern now is whether this
phthalate exposure is actually contributing to their problems when these
medical products are supposed to be helping them get better."
Phthalates,
including DEHP, are found in a wide range of consumer products, such as food
packaging, clothing, upholstery, vinyl flooring, cosmetics, and fragrances.
DEHP is the only phthalate approved for medical devices in the U.S., and its
use is unregulated. In contrast, DEHP and several other phthalates are limited
to trace amounts in children's toys and childcare products.
The new research
finds that the total daily exposure for a two-kilogram (four-pound) critically
ill infant can reach 16 mg/kg per day. The largest sources are blood products,
and endotracheal tubes placed in the airway to deliver breathing support with a
ventilator. In analyzing toxic thresholds, the researchers determined that
daily DEHP intakes are approximately 4,000 times higher than desired to prevent
a type of male reproductive toxicity, and 160,000 times higher than desired to
prevent liver injury. They say that a lower DEHP exposure could be one reason
why preemies who can be managed without a ventilator seem to have better lung
outcomes.
The researchers say
that replacing DEHP-containing products in the NICU with existing alternative
products that don't contain DEHP would be the most effective initial step in
reducing phthalate exposures during critical care. Further reductions could be attained
by addressing other sources of phthalates in the NICU, including construction
materials (such as vinyl flooring and paints); equipment such as ventilators
and incubators; soaps, lotions and other cosmetics used by staff and visitors;
and even the soaps, lotions and powders used for baby care.
"We do have to
make tradeoffs and we want to save these babies," Fox says. "But can
we save them by using alternative products that reduce their exposures to
substances that may be harming them? It seems like we could."
Comments
Post a Comment