Pulmonary hemorrhage in experimental cerebral ischemia in mongolian gerbils. Brain metabolism and lung pathology.

Pulmonary changes in acute cerebral ischemia were studied in anesthetized Mongolian gerbils, in which both carotid arteries were occluded simultaneously. Lactate, pyruvate and adenosine triphosphate (ATP) in the brain were measured as indicators of the severity of cerebral ischemia. Microscopic changes in the lung were arbitrarily scored from 0 (normal) to 3 points (severely affected) by the grade and the extent of lesions. Mean arterial pressure (MAP) was also measured through the cannulated femoral artery before and after carotid artery occlusion in a separate group of animals. Cerebral lactate was increased while ATP decreased in ischemic animals in which pulmonary changes such as intra-alveolar hemorrhages were prominent and frequent. The lung pathology score averaged 1.3 in animals with severe ischemia (lactate greater than or equal to 10 mM/Kg), 0.7 in moderate ischemia (5-10 mM/Kg) and 0.3 in mild or no ischemia (less than 5 mM/Kg), respectively, suggesting that severe brain ischemia may cause fulminant pulmonary changes. The mechanism of pulmonary lesions in acute cerebral ischemia is discussed.