Just Published!  The Evidence Analysis Library is pleased to announce the publication of the Disorders of Lipid Metabolism Saturated Fat Evidence-Based Nutrition Practice Guideline. View the guideline.

Critical Illness

CI: Introduction (2006)

Guideline Overview

Guideline Title

Critical Illness (2005) Evidence-Based Nutrition Practice Guideline

Guideline Narrative Overview

The focus of this guideline is on the nutrition care of the critically ill patient who requires nutrition support. The goals of nutrition support in well-nourished and malnourished critically ill patients are to promote acute phase and whole body protein synthesis and to prevent physiologic deterioration. Clinical judgment is crucial in the application of this guideline.

Guideline Development

This guideline outlines the most current information on nutrition support practice in the critically ill patient. The recommendations developed in this guideline were based upon a systematic review of the literature in multiple practice areas. A summary of the evidence analysis is below:
Topics include:
  • Enteral vs. Parenteral Nutrition
  • Timing of Feeding
  • Immune-Enhancing Enteral Nutrition
  • Feeding Tube Site
  • Blue Dye Use
  • Monitoring Criteria in Critical Illness
  • Monitoring Delivery of Energy 
  • Blood Glucose Control  - 09/29/09 Recommendation removed and currently under revision.
  • Energy Expenditure
  • Energy Assessment.

The recommendations involving energy expenditure are based, in part, on the work performed by the ADA indirect calorimetry evidence analysis working group, evaluating questions related to measurement of resting metabolic rate via indirect calorimetry3.

The number of supporting documents for these topics is below: 
  • Recommendations: 27
  • Conclusion Statements: 57
  • Evidence Summaries: 31
  • Article Worksheets: 112.

To view the guideline development and review process, click here.

Application of the Guideline

This guideline will be accompanied by a set of companion documents (i.e., a toolkit) to assist the practitioner in applying the guideline. The toolkit will contain materials such as the Medical Nutrition Therapy protocol, documentation forms, outcomes management tools, resources and case studies. The toolkit is currently under development and will undergo pilot-testing through the ADA's Dietetic Practice-Based Research Network prior to publication.


A repeated literature search will be done for each on a yearly basis to see if any new research has been published since the previous search was completed. The results of the search will be recorded, dated and labeled as reviewed. When new research is identified, a determination will be made about whether it could change the published recommendation or rating. If the determination is that there is no change, then the search is recorded and saved until the next annual review and no further action is taken. If the determination is that there could be a change in either the recommendation or the rating, then the question(s) will be re-analyzed following the standard ADA Evidence Analysis Process (see ADA Evidence Analysis Manual). When the analysis is completed, the expert workgroup will review and re-grade the conclusions and recommendations.

Populations to Whom This Guideline May Apply

Medical and surgical conditions where the critical illness guideline may apply include those in which the patient requires care in an intensive care unit, such as:
  • Sepsis and systemic inflammatory response syndrome (SIRS)
  • Trauma 
  • Head injury
  • Pancreatitis
  • Respiratory failure
  • Neurological injury
  • Multi-organ failure.

Study Limitations

Some ICU studies are limited by small sample size or the lack of statistical power analyses. These limitations may be reflected in statements made in reviewing evidence summaries, conclusions and associated grades of evidence. Performing power analysis and sample size estimation is an important aspect of designing an experiment, because without these calculations, the number of subjects recruited for a specific research question may be too few or too many. If sample size is too small, the study will lack the precision to provide reliable answers to the questions it is investigating. If the sample size is too large, the study may be difficult to perform and be costly.

Power is broadly defined as the probability that a test having statistical significance will reject the null hypothesis for a specified value of an alternative hypothesis. Stated more simply, power may be defined as the ability of a test to detect an effect, given that the effect actually exists.

Other Guideline Overview Material

For more details on the guideline components, click an item below:


This guideline should not be used in those for whom aggressive medical care is no longer desired. The appropriateness of a clinical intervention involves a substantial element of personal choice or values of the patient, which includes advance directives. Although nutrition support is often warranted for the critically ill patient, occasionally, support may be contraindicated due to the patient's clinical status or patient preference. Therefore, a comprehensive nutrition assessment and ongoing reassessment is necessary to determine whether the initiation or continued provision of support is appropriate.

  1. Vrees MD, Albina JE. Metabolic response to illness and its mediators. Clinical Nutrition: Parenteral Nutrition, Rombeau JL, Rolandelli RH (eds). WB Saunders, Philadelphia, 2000, pp. 21, 034.
  2. ASPEN Board of Directors: Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients.J Parenter Enteral Nutr. 26 (suppl) 1S, 2002.
  3. Compher C. Frankenfield D. Keim N, Roth-Yousey L. for the Evidence Analysis Working Group. Best practice methods to apply to measurement of resting metabolic rate in adults: a systematic review. J Am Diet Assoc. 2006; 106: 881-903.