DGEM-Leitlinie: "klinische Ernährung in der Intensivmedizin: S2k-Leitlinie (AWMF-Registernummer 073-004) der Deutschen Gesellschaft für Ernährungsmedizin (DGEM a) in Zusammenarbeit mit der Deutschen Interdisziplinären Vereinigung für Intensiv- und Notfallmedizin (DIVI ^b) sowie den Fachgesellschaften Deutsche Gesellschaft für Anästhesiologie und Intensivmedizin (DGAI ^c), Deutsche Gesellschaft für Chirurgie (DGCH ^d), Deutsche Gesellschaft für Internistische Intensivmedizin und Notfallmedizin (DGIIN ^e), Deutsche Gesellschaft für Kardiologie (DGK f), Deutsche Gesellschaft für Thorax-, Herz- und Gefäβchirurgie (DGTHG ^g) und Deutsche Sepsis-Gesellschaft (DSG^h)

Purpose Enteral and parenteral nutrition of adult critically ill patients varies in terms of the route of delivery, the amount and composition of macro- and micronutrients, and the choice of special, immune-modulating substrates. Variations of clinical nutrition affect outcome. The present guideline provides updated consensus-based recommendations for clinical nutrition in adult critically ill patients who suffer from at least one acute organ dysfunction requiring specific drug therapy and/or a mechanical support device to maintain organ function. Methods The recent guidelines of the German Society for Nutritional Medicine (DGEM) were updated according to the current instructions of the Association of the Scientific Medical Societies in Germany (AWMF) valid for a S2k-guideline. According to the S2k-guideline classification no systematic review of the available evidence was required to make recommendations, which therefore, do not state evidence- or recommendation grades. Nevertheless, we considered and commented the evidence from randomized-controlled trials, meta-analyses and observational studies with adequate sample size and high methodological quality (until May 2018) as well as from currently valid guidelines of other societies. The grading of each recommendation is solely described linguistically. Each recommendation was finally validated and consented through a Delphi process. Results In the introduction the guideline describes a) the pathophysiological consequences of critical illness possibly affecting metabolism and nutrition of critically ill patients, b) potential definitions for different disease stages during the course of illness, and c) methodological shortcomings of clinical trials on nutrition. Then, we make 69 consented recommendations for essential, practice-relevant elements of clinical nutrition in critically ill patients. Among others, recommendations include the assessment of nutritional status, the indication for clinical nutrition therapy, the timing and route of nutrition, and the amount and composition of substrates (macro- and micronutrients) as well as distinctive aspects of nutrition therapy in obese critically ill patients and those with mechanical support devices. Conclusion The current guideline provides up-to-date recommendations for enteral and parenteral nutrition of adult critically ill patients who suffer from at least one acute organ dysfunction requiring specific drug therapy and/or a mechanical support device to maintain organ function. The period of validity of the guideline is approximately fixed at five years (2018-2023).