Prerenal Kidney Injury

Prerenal Acute Kidney Injury is caused by new renal hypoperfusion that leads to a fall in GFR typically with urinary sodium avidity, as noted by a reduction in urinary sodium or the fractional excretion of sodium (FeNa) in the urine.

The hallmark of prerenal disease is its reversibility after-treatment of the underlying cause.

with the absence of structural damage to the kidney if treated promptly.
Recovery of renal function within 24 to 72 hours of volume resuscitation or
correction of renal hemodynamics helps to define prerenal AKI in isolation.

Note That :

The kidney can maintain normal renal blood flow and GFR with systemic
perfusion pressures as low as 55 to 60 mm Hg under normal conditions