Body fluid volume status in hemodialysis patients: the value of the chest radiograph.

Thirty-six pairs of chest radiographs in stable patients undergoing long-term hemodialysis were taken immediately before and after dialysis. They were evaluated in pairs, without indication as to before or after, for radiologic signs of fluid retention, and to identify if changes in these signs could be correlated with body weight and removal of body fluid by dialysis. The radiologic signs assessed were those of increased blood volume (degree of pulmonary vascularity, vascular pedicle width (VPW), transverse cardiac diameter (TD), and azygos vein width (AVW), of interstitial pulmonary edema (perihilar haze, Kerley B lines, bronchial wall thickening and thickening of the minor fissure) and pleural effusion. At least one sign of interstitial pulmonary edema was present in 28 (78%) of the pre-dialysis chest radiographs, and resolved with dialysis in all but three (8%). Pleural effusions were present in 10 (28%), of which 5 (14%) persisted after dialysis and 5 resolved. Pulmonary vascularity was found difficult to assess quantitatively, and AVW was not found to be a useful indicator of volume status. Vascular pedicle width decreased significantly with dialysis and was a useful indicator of volume status. The most reliable indicator, however, was the transverse diameter of the heart, the simplest of the measurements used. Both TD and VPW may be useful in estimating dry weight when clinical assessment is difficult.