THE RESPIRATORY distress syndrome (RDS) accounts for a large proportion of deaths in the newborn period. Controversy exists over which cases should be included, since the diagnosis cannot be made securely during life. The smaller the baby, the more likelihood of having the syndrome. Thus, according to Usher,1 14% of prematures are affected, the incidence being 50% in those weighing between 1,000 and 1,500 gm (2.2 and 3.3 lb) and 5% between 2,000 and 2,500 gm (4.4 and 5.5 lb). Fifty percent of those affected die and 80% of the deaths are between 12 and 72 hours of age. The mortality rate of babies alive with the disease at 48 hours is 25% and at 72 hours it is 11%.
Despite the improved understanding of RDS in recent years, the basic cause remains unknown. Because some infants improve after being critically ill, it is tempting to consider the disease