Adequacy of energy and protein balance of enteral nutrition in intensive care: what are the limiting factors?

OBJECTIVE To determine the factors that influence the adequacy of enteral nutritional therapy in an intensive care unit. METHODS This prospective observational study was conducted in an intensive care unit between 2010 and 2012. Patients >18 years of age underwent exclusive enteral nutritional therapy for ≥72 hours. The energy and protein requirements were calculated according to the ICU protocols. The data regarding enteral nutrition, the causes of non-compliance, and the biochemical test results were collected daily. RESULTS Ninety-three patients admitted to the intensive care unit were evaluated. Among these patients, 82% underwent early enteral nutritional therapy, and 80% reached the nutritional goal in <36 hours. In addition, 81.6%±15.4% of the enteral nutrition volume was infused, with an adequacy of 82.2%±16.0% for calories, 82.2%±15.9% for proteins, and a mean energy balance of -289.9±277.1 kcal/day. A negative correlation of C-reactive protein with the volume infused and the energy and protein balance was observed. In contrast, a positive correlation was found between C-reactive protein and the time required to reach nutritional goals. Extubation was the main cause for interrupting the enteral nutritional therapy (29.9% of the interruption hours), and the patients >60 years of age exhibited a lower percentage of recovery of the oral route compared with the younger patients (p=0.014). CONCLUSION Early enteral nutritional therapy and the adequacy for both energy and protein of the nutritional volume infused were in accordance with the established guidelines. Possible inadequacies of energy and protein balance appeared to be associated with an acute inflammatory response, which was characterized by elevated C-reactive protein levels. The main cause of interruption of the enteral nutritional therapy was the time spent in extubation.