Effect of Surgery on Brain Edema associated with Intracerebral Hematoma and Arterial Hypertension

Abstract

We studied brain edema produced by intracerebral hematoma and arterial hypertension in order to determine whether or not surgical intervention increases the edema. Intracerebral hematoma was produced by stereotactic injection of 1.0 ml of autologous blood into the subcortical white matter of cats. Arterial hypertension was induced for 30 minutes by inflation of a balloon situated in the descending aorta. The hematoma was aspirated through a burr hole or a craniectomy in the frontoparietal bone. The animals were divided into four groups; 1) intracerebral hematoma with normal arterial pressure; 2) intracerebral hematoma with arterial hypertension; 3) burr hole aspiration of hematoma during hypertension; and 4) hematoma removal and craniectomy during hypertension. A sham-operated group served as the control. Brain edema was evaluated 48 hours after the procedures, on the basis of macroscopic observation, the blood-brain barrier permeability to Evans blue, and the water content of the brain tissue. We also evaluated the animals' survival during the 48 hours after the insult. Brain edema was greater in animals with intracerebral hematoma and arterial hypertension than in those with hematoma and normal blood pressure. In the hypertensive cats there was no difference in brain edema between those not treated and those subjected to burr hole aspiration of the hematoma. However, craniectomy following hematoma removal during hypertension increased brain edema and shortened the survival time. This indicates that the combination of hypertension, hematoma removal, and craniectomy produces the greatest degree of edema and that hematoma removal per se does not affect the development of edema.