Kinetics of Respiration in Experimental Pulmonary Embolism

Previous investigators clearly demonstrated that the invariable response to diffuse embolism of pulmonary arterioles and capillaries is primarily that of tachypnea,1while the response following diffuse embolism of the moderately sized pulmonary arteries is characterized by both tachypnea and dyspnea.2It was concluded3that the underlying mechanism of these respiratory changes was different in that the rapid respiratory rate subsequent to the larger emboli was due apparently to anoxemia while that following the smaller emboli was the result of pulmonary congestion and edema. The latter appeared to operate by reflex action on the respiratory center by stimulation of the vagal nerve endings in the lungs.4 During the investigation of the cardiovascular dynamics of and the mechanism of death from experimental pulmonary embolism5we had occasion to confirm the essential differences in the character of respiration which follows moderately sized and miliary embolism. During the course