In rats anesthetized with pentobarbital, cerebal compression (CC) by impacting a space-occupying plasticine mass into the cranium produced severe pulmonary edema and hemorrhage (PEH) in 2-3 min. A regional weighting method allows a gross observation of the blood volume distribution. Concomitant with the pressor response, there was a sustained increase in the thoracic weight accompanying a decrease in the abdomen-hindquarters weight immediately upon CC. The regional weight changes were abrupt, reaching a maximum of 4-6 g in 10 s. Bilateral cervical vagotomy did not affect the pressor response, the blood volume distribution and the degree of PEH. Sympathoadrenergic blockades with reserpine, hexamethonium and phenoxybenzamine largely reduced the pressor response, the blood volume translocation and the degree of PEH. An antecedent occlusion of the abdominal circulation prevented the genesis of PEH. Occlusion of the hindquarters circulation only slightly reduced the degree of PEH. Cerebral compression apparently causes an abrupt and irreversible blood volume shift mainly from the abdominal circulation to the lungs. The translocation of blood volume is produced by an intense sympathetic activation that induces systemic vasoconstriction of the resistance vessels and probably the capacitance vessels as well. An accumulation of large amounts of blood in the lungs results in pulmonary hypertension, congestion, edema, disruption of the blood vessels and hemorrhagic changes within a short period of time.
關聯:
Proceedings of the National Science Council Republic of China Vol. 4, no. 4 pp.381-386
