Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient:

grade for the recommendation was based on the number and level of investigative studies referable to that guideline.Large studies warranting level I evidence were defined as those with ≥100 patients or those which fulfilled endpoint criteria predetermined by power analysis.The level of evidence for uncontrolled studies was determined by whether they included contemporaneous controls (level III), historical controls (level IV), or no controls (level V, equal to expert opinion).See Table 1. 1 Review papers and consensus statements were considered expert opinion and were designated the appropriate level of evidence.Meta-analyses were used to organize the information and to draw conclusions about an overall treatment effect from multiple studies on a particular subject.The grade of recommendation, however, was based on the level of evidence of the individual studies.An A or B grade recommendation required at least 1 or 2 large positive randomized trials supporting the claim, while a C grade recommendation required only 1 small supportive randomized investigation.The rationale for each guideline statement was used to clarify certain points from the studies, to identify controversies, and to provide clarity in the derivation of the final recommendation.Significant controversies in interpretation of the literature were resolved by consensus of opinion of the committee members, which in some cases led to a downgrade of the recommendation.Following an extensive review process by external reviewers, the final guideline