Phosgene Poisoning as an Example of Neuroparalytic Acute Pulmonary Edema: the Sympathetic Vasomotor Reflex Involved.

S CHMITT AND MEYERS' SHOWED IN 1957 that the acute pulmonary edema that follows vagal section is associated with a marked decrease in sympathetic inflow to the lung. It has long been known, on the other hand, that certain forms of acute pulmonary edema are associated with a marked increase in the organism's total level of sympathetic activity.2 Pursuing this dichot-omy as a possible taxonomic principle around which to order the entire syndrome, we have recently succeeded in establishing a rational classification of the many dis-parate entities of acute pulmonary edema into two grand polar groups, according to certain anatomic, physiologic, pharmaco-logic, clinical and radiologic criteria which we found empirically to be useful. One group is the hyperactive-sympathetic, characterized (1) anatomically by immediate and generalized lung hyperemia, with evenly distributed capillary and venous engorge-ment accompanying the alveolar edema ;22 3 (2) physiologically by initial high systemic and pulmonary arterial pressure,4 as indices of high sympathetic tone; (3) pharmacologically by the ameliorative effect that sympatholytic agents exert on the development and course of the lung lesions;5 (4) clinically by hypertension and hh persym-pathicotonia; and (5) radiologically by *The experimental part of this investigation was done at the satisfaction of the requirements for the degree Master of Science. The clinical correlations phase of the study was done while in attendance at the Faculty of Medicine, uniformly dense lung fields.6 This group includes epinephrine toxicity, pheochromo-cytoma, some asphyxias, some head injuries , brainstem irritation, some hypothal-mic lesions and NH4 toxicity. The other group is the hypoactive-sympathetic or neuroparalytic, characterized (1) anatomically by a late and patchy type of lung hyperemia in which venous engorgement is not usually observed, and in which ran-domlv distributed areas of alveolar exudate alternate with areas of emphysematous or normal parenchyma ;13 (2) physiologically by initial normal or low systemic and pulmonary arteria lpressure;7 (3) pharmacologically by the negative effect that sym-patholytic agents exert on the lung lesions;' (4) clinically by hypotension and shock or a tendency to shock; and (5) radiologically by the eventual development of a reticulo-granular image scattered throughout the lung fields.LS This group includes cervical vagal section, silo filler's disease, some bul-bar poliomyelitides, so-called high altitude pneumonia, hyaline membrane disease of the newborn, explosive recompression and probably paroxysmal nocturnal dyspnea. Phosgene poisoning also fits neatly into the neuroparalytic category. The present study was made in order to test in intact animals the basic principle underlying …