Protein Requirement in Critically ill Patients

Abstract

Acute critical illness is associated with proteolysis which leads to immunosuppression, poor wound healing, intensive care unit (ICU)-acquired weakness, increased mortality, and delayed recovery. It has been suggested that exogenous protein should be supplemented in sufficient amounts to mitigate this protein loss. However, there is a continuing controversy regarding the optimal amount of protein that should be administered to critically ill patients and its impact on the outcomes. The current clinical practice guidelines recommend protein intake in the range of 1.2–2.5 g/kg per day. These guidelines are mostly based on observational studies and a few randomized controlled trials. In addition, small studies showed improvement in muscle mass or handgrip strength but with no effect on ICU mortality or length of stay due to small sample size and presence of confounders such as energy intake or due to heterogeneous population. On the other hand, there is some evidence suggesting that higher protein intake provided in the 1st week of illness may actually cause harm due to inhibition of autophagy or increased ureagenesis. Therefore, there is a need for a well-designed randomized multicenter clinical trial to evaluate the optimal protein requirement in different phases of critical illness, in different subgroups, and in nutritionally high-risk patients.