Experimental Production and Prevention of Acute Edema of the Lungs in Rabbits.

Abstract

It is a common occurrence that the intravenous injection of large doses of adrenalin hydrochloride into rabbits causes the development of acute edema of the lungs and death shortly afterwards. It was found that injection of 1 cc. of 1/1000 solution of adrenalin hydrochloride (Parke, Davis & Co.) produces acute edema of the lungs in almost all medium sized rabbits.

While studying the effect of the action of adrenalin on the heart in the production of experimental myocarditis according to the method of Fleisher and Loeb, 1 we found that if the thorax of the animal is opened so that the heart and lungs are exposed to the air, and if then 1 cc. of adrenalin is administered intravenously, acute edema of the lungs does not occur. We also observed that acute edema of the lungs, which ordinarily would follow the injection of 1 cc. of adrenalin, could be prevented through the opening of the thorax by means of a cut made into the sternum in the midline and the subsequent opening of the pericardium, leaving at the same time the pleural sacs intact. This experiment was repeated several times with the same result. This observation was made independently by Dr. Leo Loeb 2 in 1909, but was never reported.

It occurred to us that the only factor that had ken altered by opening the chest was the difference in pressure between the external air and the air in the lungs. We, therefore, attempted another experiment to confirm our previous observations. The rabbit was tracheotomized and a cannula was inserted tightly in the trachea. Air from an artificial respiration apparatus was allowed to pass into the lungs at a pressure greater than that of the atmosphere, the chest remaining intact.