• Two patients with rhabdomyolysis had a low fractional excretion of sodium (FENa) that was verified repeatedly during the oliguric phase of established myoglobinuric renal failure. Volume depletion was ruled out in the first patient by lack of response to a volume challenge and in the second patient by direct hemodynamic monitoring. In both patients, return of renal function was rapid, and dialysis was unnecessary. The finding of a low FENa does not rule out myoglobinuric renal failure or necessarily indicate a volume-responsive component to the reduction in glomerular filtration rate.
(Arch Intern Med 1982;142:1216-1217)