Pulmonary embolism by small blood clots. (Physiological responses in the anesthetized dog.) Thorax 17

Embolization of the pulmonary arteries of anaesthetized dogs by large blood clots or thrombi usually causes no disturbance of heart rhythm or of respiration at the time of impaction of the embolus (Allison, Dunnill, and Marshall, 1960; Marshall, Allison, Sabiston, Bosman, and Dunnill, in preparation) and considerable recovery of lung function occurs during the first two weeks after the embolization. It is possible that human pulmonary embolism of severe degree is due to the impaction of a large embolus after multiple small emboli have caused an initial partial obstruc-tion of the pulmonary circulation. Experimental work in animals also suggests that embolism of small arteries, rather than large arteries, initiate