Indications for Clinical Nutrition

How to Decide What Type of Clinical Nutrition Support to Use

When nutritionally-at-risk patients are not able to gain sufficient nutrient intake from hospital food, then fortified hospital food or diet, enteral nutrition (EN), including oral nutritional supplements or tube feeding via nasogastric, nasoenteral or percutaneous tubes, may be required to achieve clinical nutrition requirements.1

If EN intake is not possible or determined to be insufficient, parenteral nutrition (PN) should be started in order to avoid hospital malnutrition.2,3

It is important to note that nutritional support is not restricted to the exclusive administration of EN or PN, but PN and EN may complement each other, e.g. with the use of EN plus supplemental PN.4,5

The following chart6 illustrates the determination of nutrition support:

The risks and benefits of EN versus PN must always be carefully balanced, e.g. after major surgery or during critical illness.

When Is EN Indicated?

The European Society for Clinical Nutrition and Metabolism (ESPEN) Guideline on “Clinical Nutrition in Surgery” recommends nutritional support preferably by the enteral route in perioperative patients expected to have low oral intake and who cannot maintain above 50% of recommended intake for more than seven days. In these situations, it is recommended to initiate nutritional therapy without delay.3

When Is PN Indicated?

PN is considered beneficial in the following circumstances: in undernourished patients in whom EN is not feasible or not tolerated, and in patients with postoperative complications impairing gastrointestinal function who are unable to receive and absorb adequate amounts of oral/enteral feeding for at least 7 days (ESPEN Guideline on “Clinical Nutrition in Surgery”).3

The recent ASPEN Guidelines for the “Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient” recommend postoperative PN for patients who cannot meet their energy needs orally/enterally within 5-7 days.7

When Is Supplemental PN Indicated?

In this approach, PN supplies only part of daily nutritional requirements, which supplement EN intake. The recent ESPEN Guideline on “Clinical Nutrition in Surgery” recommends that if the energy and nutrient requirements cannot be met by oral and enteral intake alone (<50% of caloric requirement) for more than seven days, a combination of enteral and parenteral nutrition is recommended.3

When Is Total PN Indicated?

In cases where EN is not tolerated, total PN can supply patients with all of their daily nutritional requirements. This form of nutrition is generally delivered by a central venous catheter.3

The Society of Critical Care Medicine (SCCM) and the American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) recommend that in patients determined to be at high nutrition risk (NRS 2002 ≥ 5 or NUTRIC ≥ 5) or severely malnourished, when EN is not feasible, it is appropriate to initiate exclusive PN as soon as possible following ICU admission.7



  • 1.Lochs H, Allison SP, Meier R, et al. Introductory to the ESPEN Guidelines on Enteral Nutrition: Terminology, definitions and general topics. Clin Nutr. 2006;25(2):180-86.
  • 2.National Collaborating Centre for Acute Care. Nutrition Support for Adults Oral Nutrition Support, Enteral Tube Feeding and Parenteral Nutrition: METHODS, EVIDENCE & GUIDANCE. London: National Collaborating Centre for Acute Care; 2006. Available from: URL:
  • 3.Weimann A, Braga M, Carli F, et al. ESPEN guideline: Clinical nutrition in surgery. Clin Nutr. 2017;36(3):623–50.
  • 4.Heidegger CP, Berger MM, Graf S, et al. Optimization of energy provision with supplemental parenteral nutrition in critically ill patients: a randomized controlled clinical trial. Lancet 2013;381(9864):385-93
  • 5.Probst P, Keller D, Steimer J, et al. Early combined parenteral and enteral nutrition for pancreaticoduodenectomy - Retrospective cohort analysis. Ann Med Surg (Lond). 2016;6:68–73.
  • 6.Fresenius Kabi Parenteral Nutrition Compendium 2018 (Fresenius Kabi Deutschland GmbH)
  • 7.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.


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