Cardiopulmonary effects of volume expansion in man: radiographic manifestations

Cardiovascular and humoral responses to extremes of sodium intake (10-1500 mEq/day) were studied. Chest radiographs of eight normal men were obtained to measure changes in heart volume and central vascular structures. Echocardiographic measurements of cardiac chamber dimensions were also obtained. Sodium loading resulted in a 16-mm-Hg increase in mean arterial pressure and increases in cardiac output, stroke volume, left ventricular end-diastolic volume, and all radiographically determined cardiac dimensions. There was direct correlation between the radiographic cardiac dimensions and left ventricular end-diastolic volume. There was no echocardiographic evidence of pericardial fluid. After sodium loading, there was enlargement of the superior vena cava, innominate veins, azygos vein, pulmonary vessels, and the aortic knob. Small pleural effusions were commonly seen. Volume expansion may cause radiographic changes that may mimic those associated with congestive heart failure. This may particularly be the case in patients with renal failure, those receiving dialysis treatment, or patients receiving large volumes of intravenous fluids.