Disturbances of the coagulatory system in patients with severe cerebral trauma II. Platelet function.

Platelet number, spontaneous aggregation, ADP- and adrenaline-induced aggregation, fibrinogen, and factors 2, 5, 7, and 10, were investigated in a series of 40 consecutive patients admitted to the clinic following severe head injury. Data were evaluated daily during the first week after trauma. Platelets were significantly decreased, particularly in non-survivors; there was no pathological spontaneous aggregation, except in a group of 22.5% of cases who had a mean age of 23.5 years. ADP-induced aggregation was negative in 69% of cases, and adrenaline-induced aggregation was absent in only two non-survivors. Fibrinogen was markedly reduced during the first five days, thereafter normalizing or increasing towards the end of the week. The other investigated values remained within their normal range of 70--130%. The results give no evidence of disseminated intravascular coagulation as a generalized and frequent phenomenon in severely head injured patients. There are, however, signs of latent consumption coagulopathy, which support data from the literature that indicate focal microthrombosis in contused brain areas.