Overview
Recognize the Syndrome Before Naming the Cause
Acute kidney injury (AKI) is an abrupt decline in glomerular filtration over hours to days.
Acute kidney injury (AKI) is an abrupt decline in glomerular filtration over hours to days. As filtration falls, nitrogenous waste accumulates and the kidneys lose control of fluid volume, potassium, other electrolytes, and acid-base balance. AKI is therefore not simply “a high creatinine.” It is a change in kidney function that can quickly become a threat to the heart, lungs, brain, and acid-base system. The first clues are often a falling urine output, a rising serum creatinine, or both. Oliguria is common but not required; some patients have nonoliguric AKI and continue to produce substantial urine while filtration and tubular function deteriorate. Creatinine also lags behind the initial injury, so a normal value does not exclude a new problem when urine output, perfusion, or risk exposures have changed. The experienced nurse looks for a trend rather than a single number: - Is urine output falling compared with the patient’s weight-based target? - Is the patient losing circulating volume or accumulating it? - Has blood pressure or perfusion changed? - Has a nephrotoxic or renally cleared medication been added? - Could...