A scintiphotographic study of pulmonary edema and hemorrhage induced by cerebral compression and norepinephrine

Pulmonary edema and hemorrhage (PEH) was induced in rats by cerebral compression and intraveneous norepinephrine. We used scintiphotographic method to demonstrate the blood volume change in the lung subsequent to the hemodynamic events that cause PEH. A specific isotope, Indium-113m, was chosen for this purpose. The isotope forms large molecular, complex with plasma transferrin (molecular weight of roughly 90,000). It is evenly distributed inside the intravascular space. Normally, the lung showed little radioactivity. After cerebral compression or intravenous norepinephrine, a marked increase in radioactivity of the lung was evident. This indicates an accumulation of blood volume in that area. All the animals developed severe PEH which was proved postmortemly. Findings of the present as well as the previous studies agree with each other and indicate that either cerebral compression or norephinephrine elicits generalized systemic vasoconstriction, causing a shift of large amount of blood into the lung. The hemodynamic changes finally result in pulmonary hypertension and subsequent PEH. The scintiphostographic method may be employed as diagnostic tool when a hypervolemic lung change is suspected. Further quantitative analysis is to be accomplished for a prospective clinical application.