Fibrin degradation products and plasminogen in newborn infants with respiratory disturbances and postnatal asphyxia

Umbilical cord blood coagulability, acidosis and intracranial hemorrhage

The relationship between blood pH and blood coagulability and alternations in the fibrinolytic system was studied using blood samples obtained from the umbilical artery of 178 cases. Further studies were performed on this relationship in 5 cases of intracranial hemorrhage detected by ultrasonography, and the following results were obtained: 1. A definitely significant correlation was noted between the hepaplastin value and blood pH and these values markedly decreased in the acidosis group. 2. Changes in FDPs and SFMC were not so obvious as changes in the hepaplastin values, but activation of the fibrinolytic system was noted in the acidosis group. 3. No consistent finding was obtained with respect to changes in At-III. 4. Among five cases of intracranial hemorrhage, abnormalities in the coagulation and fibrinolytic system were noted in cases of acidosis, indicating that presence of acidosis is associated with severe intracranial hemorrhage. 5. The necessity of future studies on biochemical changes during acidosis was discussed.

Coagulation failure in babies with rhesus isoimmunization

Serial prospective studies of coagulation status have been undertaken on 73 babies with a positive Coombs test. No abnormalities were detected in the babies with mild haemolytic disease, but seven of the 36 babies with severe haemolytic disease (cord Hb less than 11 g/dl or cord bilirubin greater than 85 mumol/1) showed evidence of transient defibrination 1 d after birth and another six had evidence of coagulation failure at birth with a platelet count of less than 150 x 10(9)/1 and a severe deficiency of multiple coagulation factors. The level of factor II and factor X was less than a fifth of the normal cord blood level in these six babies and the level of I, VII and IX was severely reduced; the factor VIII level was normal or high. Exchange transfusion started within 1 h of birth corrected the immediate factor deficiency in these six babies, but evidence of defibrination then became apparent with afibrinogenaemia, a marked fall in factors II and V, less constant falls in factors VII, IX and X, and a raised fibrin:fibrinogen degradation product level. One of these six babies died with severe pulmonary hypoplasia within an hour of birth; the other five died from haemorrhage into the lung or brain 1 1/2--6 d after birth. The very low vitamin-K dependent factor levels in the cord blood of the babies who died are presumably the result of liver damage in utero, but the subsequent changes are those of a comsumption coagulopathy. Simple screening tests at birth served to indicate which babies were at risk and it is concluded that death due to haemorrhage might be reduced by more intensive factor replacement before there is overt evidence of haemorrhage in these babies.

Haemostatic disorders and respiratory distress in the newborn

Coagulation and fibrinolysis studies were performed on 64 newborns; 16 premature infants with hyaline membrane disease (HMD), 17 newborns with other forms of respiratory distress syndrome (RDS) (8 of them were premature), 31 healthy newborns (11 of them were premature). All the babies were studied once in the first 48 hours of life. There was no significant difference between sick and healthy babies for 5 parameters; platelet count, factor VIII, fibrinogen, fibrin(ogen) degradation products, euglobulin lysis time. Factor II, VII and X were low in all infants, and premature infants had significantly lower levels compared to full term newborns. Factor V, plasminogen, alpha 2 macroglobulin (alpha 2M) and antithrombin III (AT III) levels were significantly lower in sick infants. Except for AT III, these deficiencies were not related to prematurity. No significant difference was found between HMD and other RDS. Of the 33 sick infants, 5 developed laboratory findings consistent with disseminated intravascular coagulation (DIC). The results indicate that the coagulation and fibrinolytic abnormalities reported are not specific to HMD.

[Experimental studies on proteolysis of hyaline membranes in vitro (author's transl)]

The incubation of lung tissue from premature infants with pulmonary hyaline membranes in fibrinolysis activating or fibrinolytically active solutions gave the following results. With streptokinase it was not possible to dissolve hyaline membranes (verification of the physiological lack of plasminogen in premature infants). The mean content of membranes after 24 hours showed to be 18.14 +/- 12.43% which almost corresponded to the control value of 20.24 +/- 10.54% after incubation in NaCl-solution. In comparison, solutions of plasmin, plasmin-activator or activator prepared from proactivator-plasminogen through activation with streptokinase led to a clear reduction in the membrane content, i.e. 11.00 +/- 6.50, 13.89 +/- 9.72, and 13.63 +/- 8.94%, respectively. A decrease in membranes equally strong to that after plasmin appeared after incubation for only 12 hours in trypsin (11.09 +/- 8.62%). Plasmin, plasmin-activator, and activator, but not streptokinase alone, caused also a considerable nonspecific proteolysis of the lung parenchyma which was equal to the trypsin effect, for example, with an only half as long incubation time. Since the lungs of premature infants contain the tissue activator of fibrinolysis we discuss the suggestion of Ambrus et al. (1974) to administer an injection of plasminogen to premature infants immediately after birth so that a spontaneous fibrinolysis can be favoured for developing hyaline membranes.