Major approaches to parenteral nutrology therapy in the intensive care unit: a systematic review

Introduction: In the context of parenteral nutrition, critically ill patients are associated with a state of catabolic stress and a systemic inflammatory response. Patients admitted to intensive care units (ICU) have a prevalence of malnutrition greater than 35%. Objective: It was to carry out a systematic review to list the main approaches to macro and micronutrients in parenteral therapy in intensive care units. Methods: The PRISMA Platform systematic review rules were followed. The research was carried out from June to July 2025 in the Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: 115 articles were found. A total of 45 articles were evaluated and 25 were included in this systematic review. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 20 studies with a high risk of bias and 32 studies that did not meet GRADE. It was concluded that several clinical studies critically analyzed the evolution and changes that marked the development of parenteral nutrition in intensive care units. Standard solutions of crystalline amino acids, although devoid of side effects, remain incomplete about their composition (e.g., glutamine). Lipid emulsions have evolved a lot and are now included in bi- and tri-compartmented feeding bags, allowing true total parenteral nutrition, as long as daily micronutrients are prescribed. The question of exact individual energy, macro and micronutrient needs has not yet been resolved. Many complications attributed to total parenteral nutrition are the consequence of under- or overfeeding. The historical concept of hyperalimentation is the main cause, along with the use of fixed weight-based predictive equations (incorrect in 70% of critically ill patients).