[CSF lactate and EEG changes in comatose patients with various medical conditions (author's transl)]

EEGs were recorded and initial CSF and blood lactate measurements (135) made in 104 patients who were in coma of differing severity from a variety of medical conditions. There were two patterns: in one, the CSF lactate alone was due to cerebral tissue hypoxia; and in the other factors, such as cerebral haemorrhage, meningitis or lactacidosis were predominantly present. In those with cerebral hypoxia there was a connection between the severity of the disease picture and the level of CSF lactate. In extreme cases with dissociated cerebral death, there was a mean CSF lactate concentration of 11.78 +/- 1.66 mmol/1. The prognosis of coma with concentrations above 9 mmol/l is, therefore, poor if not hopeless. To some extent one may draw prognostic conclusions from lower concentrations but this is not possible in individual cases. There was no definite correlation between the severity of EEG changes and the level of CSF lactate in coma, although there was some relationship to the degree of cerebral hypoxia. In case of meningitis, CSF lactate allowed differentiation between bacterial and viral cause, the average concentration in the former being four times normal.