Special nutrition challenges: current approach to acute kidney injury.

Acute kidney injury (AKI), previously known as acute renal failure, is defined as a sudden decline in glomerular filtration rate with accumulation of metabolic waste products, toxins, and drugs, as well as alteration in the intrinsic functions of the kidney. Reports of mortality are as high as 80%, with numerous contributing causes including infection, cardiorespiratory complications, and cardiovascular disease. Concurrent with the high prevalence of critical illness in this population is the protein energy wasting (PEW), seen in up to 42% of patients upon intensive care unit admission. The pathophysiologic derangements of critical illness, the low energy and protein stores, and uremic complications require early nutrition intervention to attenuate the inflammatory response and oxidative stress, improve endothelial function, stabilize blood sugar, and preserve lean body mass. This article addresses the unique challenges of nutrition support for the patient with AKI in the setting of critical illness and renal replacement therapy. Evidence-based recommendations are provided to meet the macronutrient and micronutrient requirements of this heterogeneous and complex patient population.