Guidelines:

Taylor B, McClave S, Martindale R, 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 (ASPEN). Crit Care Med. 2016; 44:390-438. This update expands commentary on general ICU nutrition issues and specific subsets of medical and surgical patients. There is continued emphasis on early enteral nutrition, full protein content, and relatively early parenteral route in high-risk patients in whom enteral is not an option.
PMID: 26771786

Singer P, Blaser AR, Berger MM, et al. ESPEN guideline on clinical nutrition in the intensive care unit. Clin. Nutr. 2019; 38:48-79. Provides another source of guidance on nutritional support in the ICU.
PMID: 30348463
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Strategies for Nutrition in the ICU:

Casaer MP, Mesotten D, Hermans G, et al. Early versus late parenteral nutrition in critically ill adults. N Engl J Med 2011;365: 506-17. This large, randomized study found supplementation of enteral nutrition with parenteral nutrition to reach target during the first week of ICU admission was associated with slower recovery, more complications, and more cost compared to continuing sub-target enteral nutrition alone. The study has been criticized for including patients with low risk of malnutrition and for the composition of the parenteral nutrition delivered.
PMID: 21714640
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Harvey SE, Parrott F, Harrison DA, et al. Trial of the route of early nutritional support in critically ill adults. New Engl J Med. 2014; 371:1673-84. This multicenter RCT randomized 2500 mostly non-surgical ICU patients to 5 days of parenteral vs. enteral nutrition within 36 hours of admission and found no difference in mortality. Hypoglycemia and vomiting were more common in patients receiving enteral nutrition. Of note, the rate of infections did not differ.
PMID:25271389
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Rice TW, Wheeler AP, Thompson BT, et al. Initial trophic vs full enteral feeding in patients with acute lung injury: the EDEN randomized trial. JAMA 2012;307: 795-803. This study was noteworthy for finding no difference in outcomes among ICU patients with ARDS receiving 6 days of full vs. trophic feeds.
PMID: 22307571
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Arabi YM, Aldawood AS, Solaiman O, et al. Permissive underfeeding or standard enteral feeding in critical illness. New Engl J Med. 2015; 372:2398-2408. This multicenter non-blinded RCT compared restriction of non-protein calories vs. full enteral nutrition and found no difference in mortality (in-ICU to 180 days) or adverse events. In a post-hoc analysis the permissive underfeeding group had a significantly lower rate of renal replacement therapy. The study population was not limited to patients with high baseline nutritional risk.
PMID: 25992505
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Heyland DK, Patel J, Compher C, et al. The effect of higher protein dosing in critically ill patients with high nutritional risk (EFFORT Protein): an international, multicentre, pragmatic, registry-based randomised trial. Lancet. 2023; 401:568-576. This trial of 1,300 patients found that delivery of high-protein enteral feeds to mechanically ventilated ICU patients did not improve the time to discharge alive from hospital compared to usual-dose protein feeds. Whereas previous trials have been criticized for enrolling patients at low nutritional risk, this study is noteworthy for including exclusively high-risk patients. Subgroup analysis suggests high-protein feeds might have worsened outcomes for patients with AKI and high organ failure scores.
PMID: 36708732

Practical Issues in ICU Nutrition:

Davies AR, Morrison SS, Bailey MJ, et al; ENTERIC Study Investigators; ANZICS Clinical Trials Group. A multicenter, randomized controlled trial comparing early nasojejunal with nasogastric nutrition in critical illness. Crit Care Med. 2012; 2342-8. Randomized study of 181 mechanically ventilated patients found no difference in delivered nutrition between nasojejunal and nasogastric routes of feeding. Rates of ventilator associated pneumonia, vomiting, aspiration, and mortality were similar amongst the groups while minor GI hemorrhage was higher in the NJ feeding group (13% vs 3%, p = .02).
PMID: 22809907

Reignier J, Mercier E, Le Gouge A, et al. Effect of not monitoring residual gastric volume on risk of ventilator-associated pneumonia in adults receiving mechanical ventilation and early enteral feeding: a randomized controlled trial. JAMA. 2013; 309:249-56. This large randomized study found that not monitoring residual volume in patients receiving enteral feeds was not inferior to protocolized residual monitoring in rates of ventilator associated pneumonia. Morbidity, ICU length of stay, duration of mechanical ventilation, and infection rate were also similar. A significantly greater proportion of patients in the intervention group met their calorie goal.
PMID: 23321763
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