Duration of ischemia influences the development and resolution of ischemic brain edema.

The influence of the duration of ischemia on the development and resolution of post-ischemic brain edema (SG method) was studied in anesthetized rats. Edema developed during ischemia and the amount of edema was related to the duration of ischemia (r = 0.843, p less than 0.001). With recirculation to three hours, the major determinant of the amount of edema was still the duration of the preceding ischemia (p less than 0.001). Resolution of brain edema only occurred following fifteen minutes ischemia. Post-ischemic blood-brain barrier breakdown (14C-AIB, EB albumin) was greatest following longer ischemia. Where present, the BBB leakage was simultaneously to large and small molecules.