Abstract
Changes in microcirculation during and after 3 hours of middle cerebral artery (MCA) occlusion in cats were studied with the carbon black perfusion technique. The effect of mannitol on these changes was also studied. The impairment of carbon black filling extended to the entire MCA region when transient hypotension was induced during occlusion. The filling defect was reversed with restoration of blood flow following recirculation, but the animals deteriorated with subsequent elevation of epidural pressure. Preocclusional administration of mannitol protected the microcirculation during occlusion and prevented the development of acute brain swelling associated with reperfusion. On the other hand, postocclusional administration of mannitol had an adverse effect. The pathogenesis of dynamic microcirculatory changes in relation to the development of acute brain swelling and the mechanisms of both the beneficial and adverse effects of mannitol are discussed.
