Coagulation and fibrinolytic systems in the ill preterm newborn.

Aim: The activation pattern of the clotting and fibrinolytic systems in 63 preterm infants (GA 31, 6 +/- 2.3 weeks) was studied.

Methods: The infants were divided into four groups: (i) IRDS, (ii) asphyxia at birth, (iii) sepsis, and (iv) mild infection. A control group was composed of preterm infants without any apparent disease (GA 32 +/- 1.8 weeks).

Results: During IRDS we found a systemic activation of both coagulation and fibrinolysis at birth which was represented by lower levels of ATIII (27.7 +/- 8.8%) and significantly greater levels of TAT (37.9 +/- 31.9 ng/ml), D-dimers (1242.7 +/- 206.9 ng/ml), tPA Ag (10.9 +/- 5.3 ng/ml) and PAI Ag (59.9 +/- 16.7 ng/ml) than in the control group. In the asphyxiated newborns there were no significant differences from the controls. During their seventh day of life, a significant reduction of all the analysed parameters (TAT, D-dimers, tPA, PAI) and a significant increase in ATIII were seen in the newborns with IRDS, while no significant modification was observed in the newborns with asphyxia at birth. When the newborns with sepsis were compared with those with mild infection, their TAT and PAI values proved to be significantly higher for the first tests (21.7 +/- 18.8 vs 9.2 +/- 6.9 microg/l and 53.6 +/- 14.4 vs 37.7 +/- 10.2 ng/ml respectively). During the second tests, 7 days later, only TAT (16.7 +/- 14.7 vs 6.3 +/- 4 microg/l) levels remained high while D-dimers (1094.2 +/- 400.6 vs 646 +/- 200ng/ml) and tPA (11.3 +/- 8 vs 4.9 +/- 2 ng/ml) were significantly higher in the septic group of newborns than those with mild infection.

Conclusions: These data indicate that there is an activation of the clotting and fibrinolytic systems both in the initial phase of IRDS as well as during sepsis.