[Lactate acidosis in the cerebrospinal fluid as a prognostic parameter of malacic cerebral insult (author's transl)]

Abstract

The concentrations of lactate and pyruvate were determined in 111 CSF and blood samples. The CSF and blood chemistry of 43 patients with a lateralized ischaemic cerebral insult was compared with that of a control group of 18 patients. The first tests were carried out within 24 to 48 hours and 50 follow-up determinations were undertaken in the cerebral insult group. The patients were classified according to their level of consciousness (lucid-somnolent-soporous-comatose). Covariance analysis revealed a distinct relation between the CSF chemistry and the level of consciousness of the insult patients; accordingly, a continuous increase in the lactate level from 1.54 mmol/l to 3.48 mmol/l and in the pyruvate level from 0.11 mmol/l to 0.21 mmol/l was noted. Spearman's correlation analysis also pointed to a statistically significant correlation between decreasing levels of consciousness and the CSF lactate/pyruvate quotient. The increase in the CSF/blood quotient of lactate from 1.17 to 2.14, corresponding to the decrease in the level of consciousness, also indicates that during the early stages of the disease, cerebral tissue hypoxia is reflected in the CSF rather than in the blood. Further subdivision of the groups according to whether the patients survived or died, showed that the critical maximum concentrations from the prognostic point of view are 2.74 +/- 0.19 mmol/l in the case of CSF lactate, 0.186 +/- 0.017 in the case of CSF pyruvate and 1.92 +/- 0.65 for the CSF/blood quotient of lactate. None of the patients with a CSF lactate level of 3.1 mmol/l or more survived the ischaemic cerebral insult. Thus, the above-mentioned parameters are to be regarded as important indicators of the threat to the patient's life.