Experimental Pulmonary Edema. ∗

Abstract

The frequent occurrence of pulmonary edema as one of the characteristic pathological findings in experimental shock, and following the shock syndrome in human cases, suggested methods by which it might be reproduced. Widespread congestion and petechial hemorrhages predominate as visible changes in rapidly developing shock while in cases in which the shock syndrome develops more gradually there are few petechiae, and edema is more marked. 1

Hemo-concentration is recognized as a constant feature in shock. It results from the transudation of the plasma through vascular walls. Krogh, 2 Lewis, 3 and Landis 4 support the generalization that any agent or condition resulting in capillary injury increases the permeability of the capillary walls. Edema of the tissues may result by this mechanism. Moon, et al., 5 found hemo-concentration ante-mortem, and congestion and edema post-mortem in shock arising from various causes.

Experiments were arranged for producing shock of gradual development and sub-lethal degree. A dog weighing 5.4 kg. was given daily subcutaneous injections of 7.5 mg. of histamine phosphate per kg. of body weight, diluted with saline solution 1:250. During 5 days the red cell count rose gradually from 7,200,000 to 9,400,000 and the hemoglobin increased correspondingly—a hemo-concentration of approximately 30%.