July 26, 2006 -- Costly nitric oxide gas cuts the risk of lung and brain damage in some very low-weight premature babies, two U.S.-funded studies show.
Babies born very prematurely and weighing less than 3 pounds tend to have trouble breathing. That is because their lungs are not yet fully developed. They are at high risk of permanent lung and brain damage -- even if they do not have to be put on a ventilator soon after birth.
Animal studies suggest that nitric oxide gas can help. But human studies got conflicting results. So the U.S. National Institutes of Health funded two large-scale studies. Now the early results are in.
Avoiding Lung Disease
The bottom line: Inhaled nitric oxide helps some preemies avoid permanent lung disease. And it lowers the risk of brain damage even when it doesn't prevent lung disease.
"These results are very encouraging," Children's Hospital of Philadelphia researcher Roberta A. Ballard, MD, said in a news release. Ballard led one of the studies.
"We are optimistic that this therapy could prevent long-term developmental and neurological problems in many of these children," Denver Children's Hospital researcher John P. Kinsella, MD, said in a news release. Kinsella led the other study.
Together the two studies looked at some 1,400 premature babies born at 34 weeks gestation or less. They weighed 1 to 3 pounds at birth. Neither study showed any immediate harmful side effects from inhaled nitric oxide.
The Ballard study waited one to three weeks after birth before beginning inhaled nitric oxide treatment lasting at least 24 days. After treatment, there was no lung disease in 44% of nitric-oxide-treated babies and in 37% of babies who received an inactive placebo.
Ballard and colleagues plan to follow up on the infants until 2007, when they are 2 years old. They will not make any treatment recommendations before then.
The Kinsella study started treatment within 48 hours of birth. For babies who weighed at least 2.2 pounds at birth, nitric oxide cut the risk of lung disease in half. And all of the babies had a lower risk of brain damage if treated with nitric oxide.
High Cost of Treatment
Kinsella and colleagues plan to follow up on the infants for four years. He warns that the long-term effects of this treatment -- especially its effects on brain development -- must be better understood.
Both studies appear in the July 27 issue of the New England Journal of Medicine. Accompanying the studies is an editorial by Baylor researcher Ann R. Stark, MD.
Stark notes that inhaled nitric oxide is very expensive. It costs $3,000 per day, with a cap of $12,000 per month. She warns that this treatment should be used only in clinical trials -- and not in general hospital practice -- until more is known.