DeepEN: Personalized Enteral Nutrition for Critically Ill Patients using Deep Reinforcement Learning

We introduce DeepEN, a deep reinforcement learning (RL) framework for personalized enteral nutrition (EN) in critically ill patients. Trained offline on over 11,000 ICU patients from the MIMIC-IV database, DeepEN generates 4-hourly recommendations for caloric, protein, and fluid intake tailored to each patient's evolving physiology. The model integrates a curated, clinically informed state space with a custom reward function that balances short-term physiological and nutrition-related goals with long-term survival outcomes. Using a dueling double deep Q-network with conservative Q-learning regularization, DeepEN learns clinically realistic policies that align with high-value clinician actions while discouraging unsafe deviations. Across various qualitative and quantitative metrics, DeepEN outperforms clinician-derived and guideline-based policies, achieving a 3.7 $\pm$ 0.17 percentage-point reduction in estimated mortality (18.8% vs 22.5%) and improvements in key nutritional biomarkers. These findings highlight the potential of safe, data-driven personalization of EN therapy to improve outcomes beyond traditional guideline- or heuristic-based approaches.