July 26, 2006

BIRMINGHAM, Ala. -- For the first time, University of Alabama at Birmingham (UAB) researchers and colleagues have shown nitric oxide therapy to be effective in significantly lowering the risk of long-term lung and brain injury in some premature and low birth weight infants. The results are published in the July 26 issue of The New England Journal of Medicine.

Two large, multi-center clinical trials demonstrated that when given within the first two weeks of life, inhaled nitric oxide helps prevent chronic lung disease in some premature and low birth weight infants. In addition, the treatment also appears to protect some premature newborns from brain injury when used soon after birth and at the proper dose.

Breathing problems at birth are common among babies born prematurely and those born at 38 weeks or more gestation with low birth weight. Until now, it was unclear whether there was a therapy that could help prevent potentially debilitating long-term complications associated with respiratory failure. Smaller studies have yielded conflicting results though some have shown that inhaled nitric oxide can help full-term newborns with respiratory failure get off a ventilator sooner, lowering the risk of developing breathing and other complications.

“Our study offers promising advances in the care of babies at high risk for delayed growth, breathing difficulties, delayed or impaired neurological development and other complications,” said study co-author Gary Cutter, Ph.D., UAB biostatistics professor and director of the coordinating center for one of the published trials. “Today, while many very small and premature babies survive, it is critical that techniques and therapies be developed to prevent as many of complications as possible that are caused by prematurity and low birth weight.”

According to the Centers for Disease Control and Prevention (CDC), in 2005, 12.5 percent of babies born in the United States were born prematurely or less than 37 weeks gestation. Because their lungs are not fully developed, premature infants are likely to have trouble breathing regularly or on their own. Oxygen, and in some cases a ventilator, is used to help them breathe and are designed to protect other organs such as the brain, heart, liver, and kidneys from damage while the lungs have a chance to properly develop.

However, high levels of extra oxygen or prolonged use of ventilators can cause the lungs to swell and possibly scar, leading to a chronic lung disease known as bronchopulmonary dysplasia (BPD). BPD is associated with an increased risk of ongoing health and developmental issues, including pulmonary hypertension, asthma, cerebral palsy, learning disabilities, impaired growth and cardiovascular problems. Very small babies (those born weighing less than 1,000 grams, or about 2 pounds) are at high risk for BPD even if they do not require a ventilator.

In both studies, babies treated with nitric oxide were more likely to survive without BPD at 36 weeks gestation; and in addition, in the study coordinated by UAB, the babies treated shortly after birth were less likely to show brain damage. To assess the long-term impact of treatment, the researchers will continue to follow the children from both studies for at least two years.

Combined, the two studies involved nearly 1400 low birth weight and premature infants treated at 37 medical centers. They were supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH).