Study compares three natural surfactants used to treat babies with respiratory distress syndrome

A pig-derived surfactant given to premature babies whose lungs aren't yet making the lubricant reduces mortality rates by 19 percent over two other commercially-available surfactants, researchers say.

A retrospective study of 24,883 premature babies with respiratory distress syndrome treated in 191 U.S. hospitals from January 2003 to June 2006 showed reduced mortality for all causes in babies given poractant alfa, according to lead researcher Dr. Jatinder Bhatia, chief of the Section of Neonatology at the Medical College of Georgia in Augusta. "The differences hold true whether you are sitting in a rural hospital or teaching hospital or non-teaching hospital."

The study was the first to compare all three natural surfactants used in this country to treat babies with respiratory distress syndrome. Previous studies, comparing poractant alfa with calf-derived beractant, have yielded similar results; studies comparing beractant and calfactant, also calf-derived, demonstrated no differences in mortality. The smaller studies prompted researchers to do their more comprehensive review.

Their results are being presented May 7 during the Pediatric Academic Societies Annual Meeting in Toronto.

"We are looking at a large, vulnerable population and we need this kind of data to make informed decisions," Dr. Bhatia says. He notes that the current analysis doesn't explain differences in mortality so additional studies might be needed.

About 12.7 percent of babies are born prematurely in the United States annually and about 30,000-40,000 babies have respiratory distress with surfactant deficiency.

"It's inversely related to gestational age and birth weight: the younger the baby, the higher the percentage of these babies that have little or no surfactant," says Dr. Bhatia.

Surfactant is a viscous, soapy-like substance that keeps thousands of air sacs inside the lungs from sticking together when they inflate and deflate while breathing. "If you think of the lungs as a million little balloons, these balloons collapse when the baby tries to breathe out and that is why they get into respiratory distress," says Dr. Bhatia.

Premature lungs don't immediately produce the essential lubricant, and air sacs are quickly damaged trying to function without it, even with ventilator support.

Neonatologists try to prevent damage by giving surfactant within the first hour after birth to tide the baby over until his own lungs start producing it some 48 hours later, Dr. Bhatia says. Prescribed surfactant will eventually become part of the baby's endogenous pool.

"We can give surfactant of a similar composition as Mother Nature would have made to help ameliorate the disease process. The basic premise is to give surfactant as early as possible to prevent the baby's lungs from collapsing. Once they collapse, it takes greater support from the outside to reopen these units," Dr. Bhatia says.

The surfactant effect is almost instantaneous. In fact, neonatologists are increasingly taking babies off the ventilator at the same time surfactant is given. Prenatal steroids, which accelerate lung maturity, are given to mothers when premature birth is imminent. Lung-sparing measures, such as the lowest possible ventilator setting, also are used.

Pig-derived poractant alfa, a relative newcomer approved by the FDA in 1999, was the least-used surfactant in the study population. Of the 24,883 babies in the data base provided by Charlotte, N.C.-based Premier Inc. 4,953 got poractant alfa, marketed as Curosurf; 12,653 got beractant marketed as Survanta; and 7,277 got calfactant, marketed as Infasurf".