Guidelines for the provision and assessment of nutrition support therapy in the adult critically ill patient: Society of Critical Care Medicine and American Society for Parenteral and Enteral Nutrition: Executive Summary.

Practice guidelines are not intended as absolute requirements. The use of the practice guidelines does not, in anyway, project or guarantee any specific benefit in outcome or survival. The judgment of the healthcare professional based on individual circumstances of the patient must always take precedence over the recommendations in these guidelines. The guidelines offer basic recommendations that are supported by review and analysis of the pertinent available current literature, by other national and international guidelines, and by the blend of expert opinion and clinical practicality. The “intensive care unit” (ICU) or “critically ill” patient is not a homogeneous population. Most studies in which the guidelines are based are limited by sample size, patient heterogeneity, variability in definition of disease state and severity of illness, lack of baseline nutritional status, and lack of statistical power for analysis. Whenever possible, these factors are taken into account and the grade of statement will reflect the power of the data. One of the major methodologic problems with any guideline is defining the exact population to be included.