1. Stages in the accumulation of pulmonary edema fluid
Stages in the accumulation of pulmonary edema fluid. The three columns represent three anatomic views of the progressive accumulation of pulmonary edema fluid. From left to right, the columns represent a cross section of the bronchovascular bundle showing the loose connective tissue surrounding the pulmonary artery and bronchial wall, a cross section of alveoli fixed in inflation, and the pulmonary capillary in cross section. The first stage is eccentric accumulation of fluid in the pericapillary interstitial space. The limitation of edema fluid to one side of the pulmonary capillary maintains gas transfer better than symmetric accumulation. When formation of edema fluid exceeds lymphatic removal, it distends the peribronchovascular interstitium. At this stage, there is no alveolar flooding, but there is some crescentic filling of alveoli. The third stage is alveolar flooding. Note that each individual alveolus is either totally flooded or has minimal crescentic filling. This pattern probably occurs because alveolar edema interferes with surfactant and, above some threshold, there is an increase in surface forces that greatly increases the transmural pressure and causes flooding. (Redrawn, with permission, from Nunn JF. Nunn’s Applied Respiratory Physiology, 6th ed. Copyright Elsevier/Butterworth-Heinemann, 2005.)
Source: Pulmonary Disease, Pathophysiology of Disease: An Introduction to Clinical Medicine, 7e
Citation: Hammer GD, McPhee SJ. Pathophysiology of Disease: An Introduction to Clinical Medicine, 7e; 2013 Available at: Accessed: October 29, 2017
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