Acute Kidney Injury (AKI) or Acute renal failure (ARF) is the temporary rapid breakdown of renal (kidney) function that occurs with high levels of uremic toxins (waste products of the body's metabolism) accumulate in the blood. AKI occurs when the kidneys are unable to excrete (discharge) the daily load of toxins in the urine.
Both kidneys are failing when Acute Kidney Injury (AKI) occurs. One normally functioning kidney can maintain adequate blood filtering.
AKI affects approximately 1% of patients on admission to the hospital, 2% to 5% during the hospital stay, and 4% to 15% after cardiopulmonary bypass surgery.
Based on the amount of urine that is excreted over a 24-hour period, patients with Acute Kidney Injury (AKI) are separated into two groups:
Oliguric: patients who excrete less than 500 milliliters per day (< 16 oz/day)
Nonoliguric: patients who excrete more than 500 milliliters per day (> 16 oz/day) In nonoliguric patients, the urine is of poor quality (i.e., contains little waste) because the blood is not well filtered, despite the fact that an adequate volume of urine is excreted.