Alveolar hyaline membranes in hyaline membrane disease (HMD) consist partly of fibrin. Premature infants lack serum plasminogen, thus they are unable to develop effective fibrinolysis and are defenseless against fibrin deposition. Therefore, plasminogen was tested for the prevention of HMD.
In a double-blind randomized study, 100 infants between 1.0 and 2.5 kg birthweight received plasminogen or placebo soon after birth. Factors placing the infant at risk from HMD were found to be evenly divided between control and treated groups.
Among the 51 infants who received placebo, seven developed mild, and ten developed severe respiratory distress; of these ten, five died with HMD. Two infants died from causes other than HMD.
Among the 49 infants treated with plasminogen, 13 developed mild and three developed severe respiratory distress. There was no death due to HMD. Two deaths were due to other causes.