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November 1977

Cerebral Microembolization: I. Pathophysiological Studies

Arch Neurol. 1977;34(11):660-665. doi:10.1001/archneur.1977.00500230030004

• Unilateral embolization of the brain was performed in cats by intracarotid injection of 10.5 million carbonized microspheres (15 ± 5 μ). Intracranial pressure increased from 6.1 ±1.5 to 14 ± 2.3 mm Hg within two minutes and continued to rise more slowly to 24 ± 18.3 mm Hg within four hours. Embolization caused a nonhomogenous distribution of microflow, but initially had no effect on global cerebral blood flow, nor on cortical oxygen tension. Yet, a functional suppression of cortical electrical and metabolic activity occurred. The ipsilateral EEG flattened irreversibly after 15 seconds; the contralateral EEG was transiently suppressed shortly thereafter. Arteriovenous difference of oxygen fell from 10.5 ± 0.7 to 5.3 ± 0.6 vol%, and the arteriovenous difference of glucose fell from 11.7 ± 3.9 to 2.6 ± 2.1 mg/100 ml as a consequence of reduced oxygen and glucose extraction. Subsequently, severe vasogenic brain edema, secondary ischemia, and severe functional suppression developed between two and four hours.