Reflex and humoral responses to pulmonary embolism

Abstract

The pathophysiologic response to pulmonary embolism involves mechanical blockade of the pulmonary vascular bed, release of humoral agents, and reflex responses involving receptors in the lung parenchyma and airways. Although not discussed above, arterial baroreceptor and chemoreceptor responses may also occur subsequent to hemodynamic and blood gas alterations. Most of the observations of pulmonary pathophysiologic and reflex responses of pulmonary embolism have been made in experimental animal models. Although these data appear to be applicable to patients with pulmonary embolism, detailed confirmation is lacking at this time. However, the animal observations can be extrapolated to patients with pulmonary embolism in describing many of the acute responses—tachypnea, shallow breathing, elevation of the hemidiaphragm, and abnormal blood gaseous exchange.