Optimal nutritional therapy in critically ill patients: a narrative review

Abstract

Inadequate nutrition delivery remains a pervasive issue in critically ill patients, with significant challenges in accurately measuring nutritional requirements and personalising nutrition. Current medical nutrition therapy is constrained by difficulty in objectively measuring nutritional requirements and patient responses. Both enteral and parenteral nutrition are effective, but achieving and assessing nutritional targets pose substantial challenges. The adoption of computerised nutrition monitoring is on the rise, with future strategies potentially incorporating advanced muscle monitoring tools such as ultrasound and bioelectrical impedance analysis (BIA). Early enteral nutrition has been shown to reduce complications and shorten ICU stays; however, it should be delayed in specific conditions such as gastrointestinal bleeding. When EN is not feasible, PN serves as a safe alternative. Indirect calorimetry offers a method to measure energy expenditure and guide nutritional interventions, though larger trials are necessary to validate its benefits in personalised nutrition strategies. Significant muscle mass loss is prevalent in ICU patients, necessitating optimal amino acid delivery. Protein intake should be tailored to lean mass rather than total body weight, and bedside techniques like BIA and muscle ultrasound can aid in personalising protein delivery. While high protein intake may help mitigate muscle loss, its effect on clinical outcomes remains debated. Further trials are essential to enhance personalised ICU nutrition and improve patient outcomes throughout their ICU and post-ICU care journey.