New therapy helps preemies' lungs
Nitric oxide cuts death and risk of chronic lung disease.
"Premature babies are less likely to develop chronic lung problems if they are given
inhaled nitric oxide in the first week of life, a new study says.
Preemies are subject to many life-threatening problems, with nearly one-fourth developing
respiratory distress syndrome.
About 60,000 children in the United States are born each year weighing less than
three pounds. Of those who survive, many suffer permanent lung damage, which can
slow growth, increase the possibility of infection, and result in abnormal brain
development.
The infants with respiratory distress syndrome are at a very high risk of dying
despite aggressive treatment, which can include a mechanical respirator.
"We gave inhaled nitric oxide to premature infants who were at risk for developing
chronic lung disease or dying," says Dr. Michael Schreiber, an associate professor
of pediatrics at the University of Chicago Hospitals. "By giving them the drug early
in the course of treatment, we could decrease the chances of them developing chronic
lung disease or dying," he adds.
Schreiber and his colleagues randomly assigned 207 premature infants who were receiving
mechanical ventilation to standard care plus nitric oxide or standard care and a
placebo, according to a report in the Nov. 27 issue of the New England Journal of
Medicine. The babies were born at or before 34 weeks of gestation.
The researchers found that 64 percent of the babies who received standard therapy
died or developed chronic lung disease, compared with only 49 percent of those who
received standard therapy plus inhaled nitric oxide.
Nitric oxide causes the blood vessels in the lungs to relax, allowing more blood
to get into the lung and thus allowing more oxygen to get into the infants' circulating
blood. It also acts as an anti-inflammatory that works to prevent chronic lung disease,
Schreiber says.
However, nitric oxide can increase the chance of bleeding in the brain. But in this
study, the researchers found that not only did nitric oxide not increase bleeding,
but also it actually decreased bleeding.
"We reasoned that babies with the sickest lungs are the ones most likely to have
bleeding in the brain," Schreiber says. "If we could make their lungs better, then
we hoped the overall condition of the baby would improve. In fact, that's what we
found."
This is the first time nitric oxide therapy has been used in premature infants with
mild-to-moderate disease, but severe enough to require mechanical ventilation. It
has been used successfully before in full-term and near-term babies with respiratory
problems, according to Schreiber.
There are three trials under way, Schreiber notes. "If those trials confirm our
results, then nitric oxide could be used in virtually all premature infants sick
enough to require mechanical ventilation, greatly reducing the incidence of chronic
lung disease," he says.
"Someday this will be another tool that we can use to help these extremely small
and fragile babies," Schreiber adds.
"This an intriguing and potentially exciting new therapy to try and prevent lung
injury in premature babies," says Dr. Richard J. Martin, author of an accompanying
editorial in the journal and a professor of pediatrics at Case Western Reserve University
in Cleveland.
But it is a relatively small study, he adds, and experts need to see the results
from other large, ongoing studies before making this treatment a standard part of
clinical care.
"This is the first study which has shown the benefit of nitric oxide therapy in
premature babies, and we need to worry about the safety of any new therapy in a
premature infant," he cautions."