Implementation of an Enteral Nutrition Protocol in the Cardiac Care Unit　- A Retrospective Study of Critically Ill Cardiovascular Patients.

Background: Enteral nutrition (EN) is often delayed in critically ill cardiovascular patients due to concerns about bowel ischemia, especially when under vasopressor or mechanical support. We evaluated the impact of a structured EN protocol designed to promote timely and safe nutrition delivery in the Cardiac Care Unit (CCU). Methods and Results: This single-center retrospective study compared mechanically ventilated CCU patients before (April 2019-March 2020) and after (April 2022-March 2023) protocol implementation. The protocol specified hemodynamic safety thresholds and used a peptide-based formula. Outcomes included EN-related complications, time to EN initiation, and nutritional adequacy within the first week. A total of 116 patients (58 per group) were analyzed. No significant differences were observed in vomiting (P=0.717), diarrhea (P=0.219), or bowel ischemia (P=0.364). The post-protocol group showed a significantly shorter time to EN initiation (median 39.5 vs. 76.0 h; P<0.001). By Day 5, enteral energy adequacy improved (40.8% vs. 12.3%; P<0.001), and protein adequacy increased (62.2% vs. 31.0%; P<0.001). Exploratory analyses showed no significant differences in CCU stay, ventilator-free days, or in-hospital deaths. Conclusions: The EN protocol enabled earlier initiation and improved EN delivery in high-risk CCU patients without increasing complications, offering a safe and practical approach to narrowing the gap between guidelines and practice.