Enteral nutrition-associated diarrhea (ENAD) is one of the most common gastrointestinal complications in critically ill patients receiving enteral nutrition, with a reported incidence of 22.3%-63.1%. Current management lacks a standardized nursing process and relies on individual nurse experience. This study constructs a standardized nursing care pathway driven by the Bristol Stool Form Scale (BSFS) and evaluates, in a prospective randomized controlled design, whether it reduces the severity of ENAD compared with routine ICU care. Eligible mechanically fed ICU patients are randomized 1:1 to the care-pathway group or the routine-care group, observed for 7 days (D1-D7) with a follow-up assessment on D14. The primary endpoint is the Hart diarrhea score over the observation period.

Inclusion Criteria:

• ICU critically ill patient (APACHE II score ≥15).
• Receiving enteral nutrition via nasogastric or nasojejunal tube.
• No diarrhea in the 24 hours before enrollment (stool frequency <3/day or BSFS type <5).
• Written informed consent provided by the patient or legal representative.

Exclusion Criteria:

• Known allergy to components of the enteral nutrition formula used.
• Organic bowel disease such as inflammatory bowel disease or short bowel syndrome.
• Pre-existing diarrhea at enrollment (≥3 stools/24 h and BSFS type ≥5).
• Severe hepatic insufficiency.
• Clostridioides difficile infection or other stool-culture-confirmed infectious diarrhea.
• Pregnant or lactating women.
• Currently participating in another clinical study.
• Any other condition deemed unsuitable by the investigator.

De-identified individual participant data underlying the primary study results will be made available beginning 6 months after publication of the main findings. Data will be available to researchers whose proposed use has been reviewed and approved by the study team; requests should be directed to the principal investigator.

Beginning 6 months after publication of the main study results.

Available to researchers upon reasonable request to the principal investigator, following review and approval of the proposal by the study team.