What the clinician needs to know about medical nutrition therapy in critically ill patients in 2023: A narrative review

Medical nutrition therapy (MNT) represents an essential element in the medical care of critically ill patients admitted to an intensive care unit (ICU). Increasing awareness exists that energy and nutrients not only preserve body structures such as lean body/muscle mass but also represent promising therapeutic elements to target the profound metabolic, inflammatory, endocrinologic, and immunologic alterations occurring during critical illness. However, despite intense research activities for years, diverse aspects of MNT such as the optimal timing, dosing, and composition of energy and macronutrient supply, as well as the role of micronutrients, are still an issue of debate resulting from strong heterogeneity in methods and findings of respective studies. These discrepancies are also reflected in diverging recommendations of international clinical nutrition guidelines for specific topics. In addition, implementing targeted, personalized MNT strategies in routine clinical practice underlies difficulties and challenges resulting from disease-specific issues and/or organizational, structural, and educational aspects. This narrative review aims to summarize the most recent evidence relevant to clinical practice on selected aspects of MNT in adult patients in the ICU and to provide guidance for implementing evidence-based approaches for adequate energy and nutrient supply in the ICU setting.