MECHANISM OF OEDEMA IN CHRONIC SEVERE ANAeMIA

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Abstract
Circulatory abnormalities have been studied in 45 patients with chronic severe anemia, of whom 25 had edema, including 8 with congestive heart failure. In most of the patients there was increased cardiac output and plasma volume, normal total blood volume, and decreased total vascular resistance. Edema could not be attributed to these abnormalities of general circulation or to hypoproteinaemia. A study of renal circulation showed decreased effective renal plasma flow, renal blood flow, and renal fraction of cardiac output, increased renal vascular resistance, and decreased or low normal glomerular filtration rate. These abnormalities increased with severity of the anemia but there was no consistent relation between the hematocrit and renal function. The hematocrit was less than 20% in most of the patients with edema. Renal circulatory abnormalities were greater in patients with than in those without edema. The glomerular filtration rate was significantly decreased in patients with edema, and the filtration fraction increased in those with failure. It is concluded that renal vasoconstriction occurs in both the afferent and the efferent vessels in patients without edema, that greater vasoconstriction occurs in patients with edema without heart failure, and that the greatest vasoconstriction, predominantly in efferent vessels, occurs in patients with heart failure. It is also concluded that edema in chronic anemia is due to renal retention of salt and water probably as a result of glomerulo-tubular imbalance.