Nutritional and metabolic alterations during continuous renal replacement therapy

Adequate feeding of critically ill patients under continuous renal replacement therapy (CRRT) remains a challenging issue. We performed a systematic search of the literature published between 1992 and 2012 using the quorum guidelines regarding nutrition in intensive care unit patients treated with CRRT. Daily recommended energy requirements during CRRT are between 25 and 35 kcal/kg with carbohydrates and lipids accounting for 60-70% and 30-40% of calorie intake, respectively. Daily protein needs range from 1.5 to 1.8 g/kg. Indirect calorimetry corrected for CRRT-induced CO2 diversion should be used to more correctly match calorie intake to the real needs. This type of tool is not yet available but hopefully soon. Electrolyte deficit as well as overload have been described during CRRT but, in general, can be easily controlled. Although not strongly evidenced, consensus exists to supplement important micronutrients such as amino acids (glutamine), water-soluble vitamins and trace elements.