Hyaline Membrane Disease (HMD)

Also called respiratory distress syndrome (RDS). Respiratory distress simply means that the child is having trouble breathing. It differs from respiratory distress syndrome, which is a specific condition of lung immaturity that causes respiratory distress mostly in premature babies. RDS occurs because surfactant is missing in the lungs.

Surfactant is a soap-like material normally present in the air sacs of the lungs. Without surfactant, the alveoli (air sacs) collapse when the baby breathes out. These collapsed air sacs can only be reopened with increased work of breathing. Most newborn babies do not have a normal amount of surfactant in their air sacs until 34 to 36 weeks gestation; however, some very premature infants (27 to 30 weeks gestation) will have adequate surfactant production and function and some full-term infants (37 to 40 weeks gestation) will not.

Prematurely born infants with immature lungs don’t have enough surfactant. If RDS is severe, babies require ventilators and breathing tubes. Surfactant taken from calf lung or other sources can be put into the lungs and can serve as a replacement for natural surfactant until the baby starts to manufacture her own surfactant. Surfactant treatment has considerably reduced death among very premature infants.