Early enteral nutrition in the critically ill: do we need more evidence or better evidence?

Nutritional support of the critically ill is accepted as a standard of care. Recommendations for early enteral nutrition are based on reasonable evidence but only 50% of eligible patients receive enteral nutrition within 48 h of admission to the intensive care unit. The purpose of this review is to determine how recent developments advance the current state of knowledge.

The benefits of early enteral nutrition are supported by two recent evidence-based guidelines initiatives. Early (< 48 h after intensive care unit admission) enteral nutrition may decrease hospital discharge mortality by 8-12% (grade B+ evidence-based recommendation). Five recent level II clinical trials, two of which contain major methodological flaws, are consistent with this recommendation.

Higher levels of evidence, demonstrating benefit to a patient-oriented outcome, are more likely to change practice. The addition of more level II trials to a meta-analysis composed of level II trials may not convince clinicians to change practice. A level I trial (equivalent to a phase III Food and Drug Administration licensing trial) is required to convince more clinicians to provide early enteral nutrition. A level I trial would also provide an important opportunity to validate changes in disease-oriented outcomes (measures of nutritional status) against improvements in patient-oriented outcomes.