Respiratory distress syndrome (RDS) is a condition suffered by 10-20% of all pre-term infants; it only rarely affects full-term infants. It is the leading cause of death in preemies, and the best treatment for this condition is the prevention of premature births.
Babies who are born before the middle of their last trimester lack the ability to produce a surfactant in their lungs. Without this surfactant to break the surface tension of the water building up on the inside of their alveoli, their lungs tend to collapse when they exhale. These premature infants struggle for breath, and without medical treatment they can slowly suffocate and die. Even with proper medical treatment, some still die.
Babies who do not die of suffocation can suffer from a host of other complications such as pneumonia, brain and lung hemorrhages, and blindness. The condition can cause chronic oxygen deprivation that can result in delayed brain development or outright brain damage.
The symptoms of RDS include rapid breathing, breathing that sounds labored, grunting, and a bluish tint to the lips and nails.
According to a study published in 1996, RDS afflicts 50,000 of the 250,000 premature infants born in the U.S.; 5,000 of them die.
If doctors know a woman is going into premature labor, giving her a shot of corticosteroids two to three days before delivery can help some infants avoid this syndrome.
Before surfactant therapy was introduced, the only treatment for such infants was to put them on a ventilator to force air into their lungs.
The U.S. FDA approved a surfactant in 1990 that doctors can blow into infants' lungs. The babies must still stay on a ventilator. The trade name of the first surfactant drug is Exosurf Neonatal. The FDA approved the drug in a record five months, and quickly designated it as an "orphan drug" to encourage its manufacture and availability.
The surfactant therapy has, overall, reduced the premature infant death toll by 16%. It has reduced the mortality of Caucasian infants by a whopping 41%; however, the death rate of black infants suffering from RDS has not changed much. This difference is likely due to economic and health factors; poor people can't afford good hospital care, and the infants of low-income families are likely to be sicker overall due to poor or nonexistent prenatal care, maternal malnutrition, and maternal smoking and drug use.
The surfactant drugs currently in use are the synthetic Exosurf, Survanta (which is made from cow lungs) and Infasurf (which is made from calf lungs).
References:
- http://record.wustl.edu/archive/1996/07-11-96/3471.html
- http://www.fda.gov/bbs/topics/NEWS/NEW00044.html
- http://jhhs.client.web-health.com/
- http://www.nlm.nih.gov/medlineplus/ency/article/001563.htm