Intracranial pressure changes following aneurysm rupture

Abstract
Lactate concentrations and pH were measured serially in the CSF of 52 patients with ruptured intracranial aneurysms. Measurements were made during continuous monitoring of the intraventricular pressure (IVP) in the first 12 days after the initial subarachnoid hemorrhage. A total of 226 samples of CSF were analyzed. The clinical condition of the patients was graded according to the Hunt and Hess system. The degree of cerebral arterial spasm was measured on angiograms taken on admission and again .apprx. 7 days later. Results showed that the lactate concentrations in hemorrhagic and xanthochromic CSF were significantly higher than in clear CSF, indicating lactate production from shed blood cells. Regardless of the degree of blood admixture to CSF, lactate increased with deteriorating clinical condition. Patients with a moderately increased IVP (20 to 40 mm Hg) had lactate levels of .apprx. 3 mmol/l. A rising IVP or the development of severe spasm was accompanied by a persistent elevation or an increase in lactate. Increased CSF concentrations of lactate reflected an increased production of lactate by partially ischemic cerebral tissue. A CSF lactate value above 3.5 mmol/l was associated with a poor prognosis.