Energy expenditure and delivery: does the Micawber principle apply during critical illness?

To determine from existing literature if achieving energy balance in critically ill patients improves outcome. Only randomized clinical trials were considered. Furthermore, the intent had to be that energy intake of the treatment group would reach 100% of requirement, and that the requirement was measured and not estimated.

Six studies meeting the above criteria were identified. Truly positive energy balance was rarely achieved in these studies and protein intake was a confounder because it often varied with the energy intake. The two studies in which energy balance came closest to 100% did suggest clinical benefit, but in both of these studies protein intake was also higher in the high-energy intake group.

The question posed cannot be fully answered based on the available literature. There are some signals that the pursuit of energy balance in critically ill patients might be favorable, but significant uncertainty remains.