Role of the sodium ion in acute renal failure.

Acute renal failure (ARF), an abrupt decline in renal function in its simplest terms, continues to elude precise pathophysiologic definition in human as well as experimental models. In the setting of ischemic or toxic renal injury, the role of sodium chloride as the major constituent of extracellular fluid volume (ECFV) is critically important in the maintenance of renal blood flow. Renal perfusion can be severely curtailed in states of ECFV depletion by activation of the renin-angiotensin axis leading to profound intrarenal hemodynamic alterations. This review will discuss evidence for the role of sodium chloride in the pathogenesis and modification of ischemic and toxic ARF. Much of the data arises from studies in experimental animal models of human disease. The results of clinical studies will be emphasized when available.