The concept of acute renal failure (ARF) has undergone
significant re-examination in recent years. Mounting evidence
suggests that acute, relatively mild injury to the kidney
or impairment of kidney function, manifest by changes in
urine output and blood chemistries, portend serious clinical
consequences.1–5 Traditionally, most reviews and textbook
chapters emphasize the most severe reduction in kidney
function, with severe azotemia and often with oliguria or
anuria. It has only been in the past few years that moderate
decreases of kidney function have been recognized as
potentially important, in the critically ill,2 and in studies
on contrast-induced nephropathy.