Time course of CSF lactate level in subarachnoid haemorrhage. Correlation with clinical grading and prognosis.

Cisternal and/or ventricular cerebrospinal fluid (CSF) and arterial blood lactate and acid-base balance were measured serially in 38 patients with aneurysmal subarachnoid haemorrhage (SAH). Based on daily clinical assessment, the patients and accordingly the samples were divided into two groups according to the grading of the World Federation of Neurosurgical Societies (W.F.N.S.). In cisternal CSF, samples of Grade III–V showed significantly higher lactic acidosis than those of Grade I–II. The time course of lactate and pH in poor prognosis groups had a significant tendency of lactic acidosis, especially on the 5th, 6th, 7th day after SAH. Ventricular CSF lactate increased even without CSF acidosis in Groups III–V. Measurement of CSF lactate, especially from the cisterna magna is useful as an indicator of prognosis and changes of intracranial environment following SAH.