Evidence-based guideline for nutritional assessment, enteral and parenteral nutrition, micronutrient supplementation, and special population management in the critically ill patient.
A comprehensive, evidence-based clinical guideline for the nutritional assessment, energy and protein delivery, enteral and parenteral nutrition management, micronutrient supplementation, immunonutrition, and special population considerations in the critically ill adult patient. This resource synthesizes recommendations from the major international nutrition and critical care professional societies, including their published guidelines on nutrition support in the adult critically ill patient, clinical nutrition in the intensive care unit, and systematic reviews of randomized controlled trials, into a single integrated reference for intensivists, critical care dietitians, pharmacists, and advanced practice providers who manage nutritional therapy in the ICU.1 2 3 4 5 6
Malnutrition is prevalent among critically ill patients, with studies reporting that 30% to 50% of ICU admissions are malnourished or at high nutritional risk. Critically ill patients experience profound catabolic stress resulting in accelerated skeletal muscle proteolysis, negative nitrogen balance, immune dysregulation, and impaired wound healing. The metabolic response to critical illness evolves through distinct phases — the acute ebb phase (first 24 to 48 hours), the catabolic flow phase (days 2 to 7), and the anabolic recovery phase (beyond day 7) — each with different nutritional implications. Providing optimal nutrition support — neither overfeeding nor underfeeding — is associated with improved clinical outcomes including reduced infectious complications, shorter duration of mechanical ventilation, decreased ICU length of stay, and lower mortality. The evidence base for nutrition in the ICU has expanded substantially with landmark trials including EDEN, PERMIT, TARGET, NUTRIREA-2, EAT-ICU, and EPaNIC, enabling more precise recommendations than ever before.
Contents:
| Part | Title | Coverage |
|---|---|---|
| Part 1 | Nutritional Assessment & Energy/Protein Requirements | Nutrition screening tools (NUTRIC score with complete scoring table, NRS-2002, mNUTRIC); limitations of traditional biomarkers (albumin, prealbumin); body composition assessment (ultrasound, CT at L3); indirect calorimetry (gold standard); predictive equations (Penn State, Mifflin-St. Jeor with formulas); weight-based caloric estimates; protein targets (1.2-2.0 g/kg/day); obesity adjustments (BMI categories) |
| Part 2 | Enteral Nutrition | Early EN timing (within 24-48 hours); gastric vs post-pyloric route; initiation and advancement protocols; formula selection (polymeric, semi-elemental, disease-specific); GRV management (threshold >=500 mL); prokinetic agents (metoclopramide, erythromycin); complications (aspiration, diarrhea, refeeding syndrome); EN during prone positioning; EN during vasopressor therapy and mesenteric ischemia risk |
| Part 3 | Parenteral Nutrition & Micronutrients | PN indications; timing controversies (supplemental PN day 7 vs earlier); composition (dextrose, amino acids, lipid emulsions); monitoring (electrolytes, TG, glucose, LFTs); PN complications; PN-to-EN transition; thiamine and refeeding syndrome prevention; vitamin C (CITRIS-ALI, VITAMINS trials); vitamin D deficiency; selenium, zinc, copper; complete refeeding syndrome protocol |
| Part 4 | Immunonutrition & Special Populations | Arginine, glutamine, omega-3 fatty acids, antioxidants; REDOXS trial and when to avoid immunonutrition; sepsis (trophic vs full feeds); burns; trauma and TBI; acute pancreatitis; ECMO; obesity (high protein hypocaloric); chronic critical illness; open abdomen; CRRT; glycemic control; perioperative feeding protocols; quality metrics |
McClave SA, Taylor BE, Martindale RG, et al. “Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.).” JPEN J Parenter Enteral Nutr. 2016;40(2):159-211. DOI: 10.1177/0148607115621863 ↩︎
Compher C, Bingham AL, McCall M, et al. “Guidelines for the Provision of Nutrition Support Therapy in the Adult Critically Ill Patient: The American Society for Parenteral and Enteral Nutrition.” JPEN J Parenter Enteral Nutr. 2022;46(1):12-41. DOI: 10.1002/jpen.2267 ↩︎
Singer P, Blaser AR, Berger MM, et al. “ESPEN guideline on clinical nutrition in the intensive care unit.” Clin Nutr. 2019;38(1):48-79. DOI: 10.1016/j.clnu.2018.08.037 ↩︎
Heyland DK, Dhaliwal R, Jiang X, Day AG. “Identifying critically ill patients who benefit the most from nutrition therapy: the development and initial validation of a novel risk assessment tool.” Crit Care. 2011;15(6):R268. DOI: 10.1186/cc10546 ↩︎
Rahman A, Hasan RM, Agarwala R, Martin C, Day AG, Heyland DK. “Identifying critically-ill patients who will benefit most from nutritional therapy: further validation of the ‘modified NUTRIC’ nutritional risk assessment tool.” Clin Nutr. 2016;35(1):158-162. DOI: 10.1016/j.clnu.2015.01.015 ↩︎
Heyland DK, Dhaliwal R, Wang M, Day AG. “The prevalence of iatrogenic underfeeding in the nutritionally ‘at-risk’ critically ill patient: Results of an international, multicenter, prospective study.” Clin Nutr. 2015;34(4):659-666. DOI: 10.1016/j.clnu.2014.07.008 ↩︎
Comprehensive guide to immunonutrition (arginine, glutamine, omega-3 fatty acids, antioxidants), and nutrition management in special ICU populations including sepsis, burns, trauma, TBI, acute pancreatitis, ECMO, obesity, chronic critical illness, open abdomen, and CRRT.
Comprehensive guide to parenteral nutrition in the ICU: indications, timing controversies, composition, lipid emulsions, monitoring, complications, transition to EN, and micronutrient supplementation including thiamine, vitamin C, vitamin D, selenium, zinc, and refeeding syndrome prevention.
Comprehensive guide to enteral nutrition in the critically ill: timing of initiation, gastric vs post-pyloric access, advancement protocols, formula selection, gastric residual volume management, prokinetic agents, complications including aspiration and refeeding syndrome, and EN during prone positioning and vasopressor therapy.
Comprehensive guide to nutrition screening tools (NUTRIC score, NRS-2002, mNUTRIC), limitations of traditional biomarkers, body composition assessment, indirect calorimetry, predictive equations, caloric and protein targets, and obesity adjustments in the critically ill adult.