169 A. NUTRITION ASSESSMENT A1. A determination of nutrition risk (eg, nutritional risk screening [NRS 2002], NUTRIC score) should be performed on all patients admitted to the ICU for whom volitional intake is anticipated to be insufficient. High nutrition risk identifies those patients most likely to benefit from early EN therapy. A2. Nutrition assessment should include an evaluation of comorbid conditions, function of the gastrointestinal (GI) tract, and risk of aspiration. The use of traditional nutrition indicators or surrogate markers is not suggested, as they are not validated in critical care. A3a. Indirect calorimetry (IC) should be used to determine energy requirements, when available and in the absence of variables that affect the accuracy of measurement. (Very Low) A3b. We suggest feeding 12-25 kcal/g (ie, the range of mean energy intakes examined) in the first 7-10 days of ICU stay. A4. An ongoing evaluation of adequacy of protein provision should be performed. B. INITIATE ENTERAL NUTRITION B1. Nutrition support therapy in the form of early EN should be initiated within 24–48 hours in the critically ill patient who is unable to maintain volitional intake. (Very Low) B2. We recommend that either PN or EN is acceptable. Evidence grade: High, Strength of GRADE recommendation: Strong. DEFINITIONS Nutrition therapy refers specifically to the provision of either enteral nutrition (EN) by enteral access device and/or parenteral nutrition (PN) by central venous access. Standard therapy (STD) refers to provision of intravenous (IV) fluids, no EN or PN, and advancement to oral diet as tolerated. Grading System Guidelines are graded from High to Very Low as noted in parentheses or based on expert consensus. For more information on the grading system, please refer to McClave SA, et al. JPEN J Parenter Enteral Nutr. 2016;40(2):159-211. GUIDELINES FOR NUTRITION SUPPORT THERAPY IN THE ADULT CRITICALLY ILL PATIENT