Enteral nutrition–related hyperglycemia in critical illness: cascade conceptual model and implications for precision nursing—a systematic review

Background: Hyperglycemia is a common complication in critically ill patients receiving enteral nutrition (EN). This review synthesizes evidence on its mechanisms, epidemiology, clinical implications, and nursing management to support precision glycemic care. Methods: A systematic literature search identified 45 eligible studies, including randomized trials, retrospective studies, reviews, guidelines, and expert consensus statements. Given the lack of a universally accepted definition, enteral nutrition-related hyperglycemia was pragmatically defined as blood glucose ≥7.8 mmol/L occurring within 24-72 h after initiation of enteral nutrition. Results: Reported incidence varies widely, from approximately 30-47% in general ICU populations to 60-80% following cardiac surgery, reflecting differences in definitions, patient characteristics, timing, and nutritional protocols. Based on thematic integration of existing evidence, we propose a six-level conceptual cascade framework, linking metabolic vulnerability, stress-hormone activation, exogenous substrate load, enteroinsular axis dysfunction, inflammation-mediated insulin resistance, and microbiota dysbiosis. Corresponding nursing strategies include diabetes-specific formulas, optimized feeding regimens, continuous glucose monitoring, and individualized insulin protocols within multidisciplinary care. These strategies may improve glycemic control; however, evidence for clinical outcome benefits remains limited and heterogeneous. Conclusion: Further prospective studies are needed to validate the model and refine precision nursing strategies.