Radiographic diagnosis of cardiogenic pulmonary edema

Development of pulmonary edema (increased extravascular lung water) is a common and sometimes life-threatening clinical problem in critical-care unit patients. There are three principal causes: cardiac failure, overhydration, and increased pulmonary capillary permeability. Among these, cardiogenic edema consists of left heart failure and overhydration. Determining the specific cause of any given case of pulmonary edema is important and leads to more rapid and definitive treatment. A plain chest film can often explicate the cause of edema with a high degree of accuracy if careful attention is given to certain radiographic features. The principal features useful for correctly determining the cause of edema in a high percentage of cases are the distribution of pulmonary blood flow, distribution of pulmonary edema, and vascular pedicle width. Ancillary features are pulmonary blood volume, bronchial cuffing, septal lines, pleural effusion, and air bronchograms. Cardiac size and shape as well as specific intracardiac calcifications could also help distinguish cardiogenic from noncardiogenic pulmonary edema.