Permissive Underfeeding Could Improve ICU Outcomes

Permissive enteral underfeeding of critically ill patients is associated with slightly lower mortality than feeding to a standard target, according to a new study.

Researchers at King Saud Bin Abdulaziz University for Health Sciences (Riyadh, Saudi Arabia) conducted a randomized, single-center study involving 240 intensive care unit (ICU) patients randomly assigned to one of two enteral feeding regimens. The permissive underfeeding protocol aimed for a caloric intake of 60% to 70% of calculated requirements; the target feeding protocol aimed to feed 90% to 100% of calculated need. Within each group, the patients were further randomized to two different target blood glucose levels to investigate intensive insulin therapy (IIT, 4.4-6.1 mmol/L) compared with that of conventional insulin therapy (CIT, 10.0 to 11.1 mmol/L). The patients were fairly evenly split among the four groups, and were well-matched for baseline characteristics.

The results showed that 28-day all-cause mortality rate was lower, although not statistically so, in the underfeeding group than the target-feeding group; the same was true for the 180-day mortality rate. Hospital mortality, however, was significantly lower with underfeeding than with target feeding, with several factors accounting for the lack of a statistically significant difference in the 28-day mortality rate; chief among these is the low actual caloric intake, especially in the target group, where caloric intake was only 71%, despite the planned goal of 90% to 100%. There were no significant differences in outcomes with IIT or CIT, although intensive therapy significantly increased the risk of hypoglycemia. The study was published in the January 2011 issue of the American Journal of Clinical Nutrition.

"The provision of full caloric requirement during critical illness may not be a good thing to do,” said lead author Yaseen Arabi, MD, of the department of intensive care medicine. "When we get sick, we lose our appetite. Forcing ourselves to eat more does not necessarily make us better. In fact, this may make things worse by augmenting oxidative stress, inflammation, insulin resistance and other mechanisms.”

Related Links:
King Saud Bin Abdulaziz University for Health Sciences