Nutritional papers in ICU patients: what lies between the lines?

Abstract

The abundance of literature related to nutritional support reflects its recently recognised role in preventing metabolic complications and gut dysfunction during critical illness. However, some published studies lack relevance to critically ill patients, as a result of the selection of subjects and outcome variables, or flaws in the study design, as well as in the type, composition, timing, route of administration and amount of nutritional support given. This review will highlight these confounding factors by describing two imaginary (but typical) clinical trials and by analysing some studies published. The point at issue is that basic quality requirements, such as the formulation of a prospective hypothesis and the delineation of the effects of the reference treatment, are often lacking in many studies published. Data analysis was often found to be biased by the absence of statistical power calculation and intention-to-treat analysis. Globally, studies designed to assess the effects of nutritional support on the outcome of critically ill patients, rarely fulfil basic quality requirements and should therefore be interpreted cautiously. We suggest simple strategies or study design that will allow important questions to be answered by future clinical trials.

Fish Oil in Critical Illness: Mechanisms and Clinical Applications

“…This heterogeneity means that large numbers of patients are required to demonstrate an effect. (80) Third, the delivery of nutrition and micronutrients is frequently interrupted or poorly tolerated in ICU patients, thus resulting in decreased delivery of the agent being studied, especially if it is enteral. Fourth, in many studies of enteral and parenteral nutrients, many agents are frequently combined into one formula, and therefore the effect produced by a single agent cannot be determined.…”

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“…However, in those patients who stayed in the ICU for the entire study period, the nutritional goals were achieved quite successfully: the mean intake of calories in these patients was 19.0 ± 6.0 kcal/kg per day with no detectable differences between study groups. The standardization of nutritional support has also been difficult in other trials concerning critically ill patients [ 23 ].…”

Nutritional support for critically ill children

“…Others have found poor evidence that early enteral nutrition is better than early parenteral nutrition (Peter 2005;Simpson 2005), although this is controversial (Heyland 2003). Part of the reason for the controversy is that many of the trials were not of optimal quality (Preiser 2003). "The point at which 'safe' starvation ends and malnutrition-related complications begin has yet to be defined" (Preiser 2003).…”