Acute Kidney Injury

This is a unique question-and-answer chapter for surgical residents and trainees, concentrating on the acute kidney injury (AKI). The term acute renal failure (ARF) has been largely replaced by AKI. AKI is considered a more accurate description of an acute loss of kidney function that is of clinical relevance but that does not necessarily result in overt organ failure. A patient who has a urine output of less than 0.5mL/kg/hour for 6 hours is one of the Kidney Disease: Improving Global Outcomes (KDIGO) criteria for defining AKI. This patient classifies as stage 1 AKI. A serum creatinine increase of 2 times over baseline the past 48 hours meets the KDIGO criteria of 2.0-2.9 times increase from baseline for stage 2 AKI. Furthermore, anuria for at least 12 hours meets the definition of stage 3 AKI. The KDIGO criteria uses only changes in the biomarkers of serum creatinine and urine output for adults.