Mechanisms of Intracisternal Veratrine Pulmonary Edema

¹ Division of Cardiovascular Research, Chicago Medical School, University of Health Sciences, Chicago, Illinois

Pulmonary edema (PE) caused by central nerve irritation is a known clinical condition. Our study was undertaken in order to investigate the mechanism of this condition. PE was induced in 29 dogs by a standard technique of intracisternal veratrine. The standard method was studied in ten dogs. Extreme elevation of left ventricular systolic pressure (LVSP) occurred, followed by elevation of the left ventricular diastolic pressure (LVEDP) to a very high level, even reaching 80 mm Hg. Extreme increase of the dp/dt was also noted. PE was severe. In five dogs, the procedure was performed after spinal transection at T-4. In these animals, LVSP rose less, LVEDP rose moderately, and pulmonary edema was minimal. In 13 dogs, the procedure was performed after bilateral stellectomy and/or vagotomy. LVSP rose as in standard experiments, LVEDP rose moderately, and PE was minimal or absent. These results are evidence that CNS irritation is followed, not only by vasoconstriction, increased venous return, and cardiac overloading, but also by decreased compliance of the left ventricular wall. Spinal transection decreases ventricular overload by preventing peripheral constriction and adrenal catecholamine secretion. Stellectomy prevents changes of left ventricular compliance mediated through cardiac nerves without affecting those caused by circulating catecholamines.