Study Objective This clinical trial primarily aims to investigate whether semi-elemental enteral nutrition (SEN) improves gastrointestinal tolerance in patients with severe traumatic brain injury (TBI) and to evaluate its impact on clinical outcomes. The safety profile of SEN will also be assessed.

Key Research Questions Does SEN reduce the incidence of acute gastrointestinal injury (AGI) in severe TBI patients?

Study Design

Participants will be randomized 1:1 into either:

Intervention group: Receives SEN initiated within 48 hours post-injury and continued for ≥7 days.

Control group: Receives standard enteral nutrition over the same period.

Background:

Patients with traumatic brain injury (TBI) frequently exhibit gastrointestinal dysfunction secondary to central nervous system impairment. This dysregulation impairs nutrient absorption, exacerbates systemic inflammation, and compromises clinical recovery trajectories. Emerging evidence suggests that semi-elemental enteral nutrition (SEN)-featuring hydrolyzed macronutrients with low-osmolality formulations-may mitigate these sequelae by reducing digestive burden and enhancing mucosal healing. However, robust clinical evidence supporting its superiority over standard enteral feeding in severe TBI populations remains limited.

Objectives:

Primary Objective:

To evaluate the efficacy of semi-elemental enteral nutrition (SEN) in improving gastrointestinal tolerance during the acute phase (first 7 days post-injury) in patients with severe traumatic brain injury (TBI).

Secondary Objectives:

1. To assess gastrointestinal complications within 7 days of enteral nutrition initiation, including:

   Incidence of diarrhea and diarrhea-free days Incidence of constipation Incidence of vomiting Incidence of gastroparesis Incidence of abdominal distension Time to first onset of gastrointestinal intolerance symptoms Duration of gastrointestinal intolerance symptoms

2. To evaluate clinical outcomes:

   Hospitalization duration (total and ICU-specific) 6-month mortality and functional recovery

3. To determine safety profiles:

Infection rates Pneumonia incidence Other adverse events

Study Design:

A multicenter, randomized, double-blind, parallel-group exploratery trial will be conducted. 100 severe TBI patients will be allocated 1:1 to intervention (SEN formula) or control (standard formula) arms within 48 hours of injury.

Inclusion Criteria:

• Aged 18-75 years;
• Clinically diagnosed with closed traumatic brain injury;
• Glasgow Coma Scale (GCS) score ≤ 8;
• Ability to initiate enteral nutrition within 48 hours post-injury;
• Expected need for enteral nutrition support ≥3 days based on clinical assessment (Nutritional Risk Screening 2002 [NRS2002] score ≥3).

Exclusion Criteria:

• GCS=3 with bilateral fixed and dilated pupils;
• Hemodynamic instability or respiratory failure: mean arterial pressure <70mmHg, PaO2/FiO2<150, PaCO2<30 mmHg or >45 mmHg, or lactate >5 mmol/l;
• Contraindications to both nasogastric and nasojejunal tube placement, or inability to complete tube placement within 48 hours of onset;
• Contraindications to enteral nutrition therapy or semi-recumbent positioning;
• Pre-existing intellectual disability or physical disability affecting outcome assessment;
• Gastrointestinal abnormalities likely to affect gastrointestinal function, such as short bowel syndrome (defined as total small bowel length ≤122 cm), ulcerative colitis, Crohn's disease, or any form of ostomy;
• Body mass index (BMI) <18kg/m2;
• Concomitant abdominal injury or extracranial injury with AIS score >3 in any region;
• Presence of malignancy, severe cardiac insufficiency (ejection fraction <50%), severe hepatic failure (Child-Pugh score ≥7), or severe renal failure (glomerular filtration rate ≤30 mL/min or serum creatinine ≥4mg/dL) at NICU admission;
• Concurrent severe disease with expected survival ≤14 days;
• Pregnancy, within 30 days postpartum, or breastfeeding;
• Refusal of treatment or receipt of palliative care;
• Patient or family declines informed consent;
• Current participation in another interventional clinical trial.

Will be determined in accordance with sponsor requirements.