Assessing the Risks, Benefits of Oxygen Therapies for Preemies
Posted Jun 07 2010 12:05pm
A gentle oxygen-delivery technique is as effective as a more
invasive one for treating very preterm infants, according to
a new study. The researchers also found that slightly lower oxygen
levels decrease the risk for eye damage but may raise the risk
Very preterm infants—those born at 24 to 27 weeks of
gestation instead of the full term of about 40 weeks—face
a number of health challenges. Even with todays high-tech neonatal
intensive care units, about 1 in 5 very preterm babies does not
Extremely preterm babies are traditionally treated with an
artificial surfactant—a viscous substance that helps keep the
lungs air sacs open—and a ventilator and to aid breathing.
But a growing number of doctors have started to use a less-invasive
method called continuous positive airway pressure (CPAP). A technique
thats long been used for adults with sleep apnea, CPAP relies
on a machine to blow air through a preterm infant's nostrils
to gently inflate the lungs. Until now, the 2 techniques hadnt
been compared in a large clinical trial. Also unknown was the
ideal blood oxygen level for these newborns.
To explore the treatments, scientists at 20 medical centers
enrolled 1,316 very premature infants in a 2-pronged study. The
study received primary funding from NIHs Eunice Kennedy Shriver
National Institute of Child Health and Human Development (NICHD),
with additional support from NIH's National Heart, Lung and Blood
Institute (NHLBI) and National Center for Research Resources
(NCRR). The results were published in 2 separate papers in the
May 27, 2010, issue of the New England Journal of Medicine.
In the first prong of the study, infants were randomly assigned
to receive oxygen either by CPAP or by ventilation with surfactant.
If infants in the CPAP group couldnt achieve adequate oxygen
levels, they were placed on a ventilator. Of those who received
CPAP initially, 83% required a ventilator tube in the windpipe,
and 67% received surfactant.
The researchers found that, although the 2 therapies had nearly
identical death rates and evidence of a lung disorder, children
placed on early CPAP fared somewhat better by other measures.
They had better survival rates and were less likely to need breathing
therapy a week after birth. They were less likely to need steroid
treatment for their lungs, and they spent less time overall on
ventilators. Initial CPAP treatment also led to better survival
rates for the earliest preterm infants, born at 24 to 25 weeks
In the studys second prong, infants were randomized to receive
either a higher or lower target range for blood oxygen saturation.
Higher oxygen levels had already been linked to an increased
risk of retinopathy of prematurity, a potentially blinding eye
The researchers found that about half as many infants in the
lower oxygen group developed retinopathy of prematurity compared
to those in the higher oxygen group (about 9% compared to 18%).
However, more infants in the lower oxygen group died—about
20%—than in the higher level group (16%). The evidence
suggests there may be 1 additional death for every 2 cases of
severe retinopathy prevented.
"Balancing the benefits of supplemental oxygen against the risks
in these very premature babies has been a concern of doctors
and parents for decades," says NHLBI Acting Director Dr.
Susan B. Shurin. "The results of this large clinical trial
will help inform management decisions to improve chances of survival
and reduce complications associated with breathing problems in
these vulnerable patients."