Ischemic Brain Damage in a Model of Acute Subdural Hematoma

Abstract

Ischemic brain damage is the most important neuropathological finding in humans who die after acute subdural hematoma: however, its causes are poorly understood. We have produced acute subdural hematoma in the rat by injecting 400 μl of autologous blood (∽20% of intracranial volume) into the subdural space. Extensive areas of ischemic damage, involving 14 to 16% of the volume of the hemisphere, developed in this model at 4 and 24 hours after the lesion. The hematomas were associated with a brief peak in intracranial pressure (51 mm Hg), which remained at three times normal levels (14 mm Hg) for 3 hours. In this model, therefore, ischemic damage appears to be due to the local effects of blood overlying the cortex at 4 hours after the ictus, rather than to globally raised intracranial pressure. The implications for the pathophysiology of acute subdural hematomas in humans are discussed. (Neurosurgery 27:433-439, 1990)