Acute Energy Deficit and ICU-Acquired Infections

Abstract

The relationship between chronic protein-energy malnutrition and impaired immune response or infections was identified one century ago. However, the impact of acute energy deficit on the intensive care unit (ICU)-acquired infections remains largely unknown. Indeed, energy deficit results in an early energy gap during the first week of ICU stay, which is never overcome thereafter, especially in the most severely ill patients. Moreover, cumulated energy deficit buildup during the first days of ICU stay and exceeding 8,000−10,000 kcal seems to be an independent factor contributing to complications, especially Staphylococcus aureus infections. Over the past few years, interest has grown in trying to understand the regulation of virulence determinants by host-nutrient availability in many pathogens, such as S. aureus. Recent findings suggest that energy deficit acts as a real “nutritional stress” in critically ill patients and involves these host–pathogen interactions, especially with S. aureus. Limitations of methods assessing energy balance in the ICU suggest it is more reasonable to limit rather than to fill the energy deficit in critically ill patients. The further development of clinical tools for assessing body composition, especially body cell mass, could help to determine how acute energy deficit facilitates the predisposition to ICU-acquired infections.