New neonatal problems of blood coagulation and fibrinolysis. I. The change of plasmin inhibitor levels in the newborn infant.

"Hemorrhage in the newborn" has long been recognized as merely a result of vitamin K deficiency. However, it is also recognized that fibrinolysis, especially the correlation between the plasminogen-activator and plasmin-inhibitors, play an important role in this disease during the neonatal period. With this in mind, we compared thromboelastograms (TEG) from samples with and without urokinase (plasminogen-activator). In 13 out of 15 newborn infant blood-samples (prior to and after addition of urokinase) the thromboelastogram showed the pattern of a consumption coagulopathy. The change in the concentration of plasmin-inhibitor during the neonatal period was also measured using alpha2-macroglobulin, alpha1-antitrypsin and antithrombin III with M-partigen-plates. The value of alpha2-macroglobulin showed normal adult levels but the value of alpha1-antitrypsin and antithrombin III did not even reach half of the adult level. During the newborn period, the plasmin-inhibitor shows a remarkable lowering tendency and it may be surmised that with such a lowering tendency plasmin-inhibitor may constitute an exceptionally large handicap when the activator is working. This is especially true in the case of lung hemorrhage since the activator arises from a severe pathological state in the lungs and in addition because this is complicated by the lowering of plasmin-inhibitor. These results indicate that the low level of plasmin-inhibitors work synergistically with the high value of activator. The low level of antithrombin III could be the reason for coagulation disorders such as disseminated intravascular coagulation, (DIC).