Changes in the fibrinolysin system in infantile and adult respiratory distress syndrome (ARDS), caused by trauma and/or septic shock in patients and in experimental animals.

Five hundred premature infants were treated on a randomized double-blind basis with human plasminogen or placebo. We found that in premature infants plasminogen levels are low; thus, defense against intra-alveolar fibrin deposition during birth trauma is reduced. A significant decrease in the incidence of respiratory distress syndrome-hyaline membrane disease and death was seen in the treated infants. Infants with established respiratory distress syndrome were treated with human plasmin or placebo. A significant decrease in death rate was found in the treated infants. Decreased plasminogen and anti-thrombin III (AT-III) levels were found in patients with adult respiratory distress syndrome and/or septic shock. These levels returned to normal within 14 days in survivors, but remained depressed in those who died. It was thought that these parameters may have diagnostic and predictive values. In experimental animals, injection of E. coli endotoxin or oleic acid produced an adult respiratory distress syndrome type phenomenon. This was also accompanied by decreases in plasminogen levels, with recovery in the survivors. It is suggested that plasminogen and anti-thrombin III should be explored as auxiliary therapeutic agents in adult respiratory distress syndrome.