Localized multiple minute pulmonary embolism and breathing

Abstract

During continuous spirometric recording of breathing, 75–μ glass bead emboli were delivered selectively to single lungs or lung lobes while the remaining lung areas were maintained functionally intact and free of emboli. Postmortem digestion of the lungs revealed the distribution of the emboli and demonstrated complete localization within single lungs or lobes in 12 of 16 experiments. In all instances the frequency of breathing increased and tidal air decreased in a pattern indistinguishable from that attending bilateral multiple minute pulmonary embolism. These effects were abolished by vagotomy but survived inhalation of pure oxygen. Comparison of the quantitative relationship between emboli dose and magnitude of response in localized with that in generalized pulmonary embolization suggests that, within limits, the intensity of the tachypnea is determined by the number of emboli injected regardless of the identity of the gross lung area in which they lodge or the degree of their concentration or dispersion within areas in which they lodge and seems not to favor associated hemodynamic factors as the agency initiating the reflex. Submitted on January 3, 1961