What are the general recommendations for nutrition in patients with Traumatic Brain Injury (TBI) in the Intensive Care Unit (ICU)?

Nutritional Management for Traumatic Brain Injury Patients in the ICU

Enteral nutrition should begin within 72 hours of TBI admission and achieve full replacement by 7 days, as early initiation and achieving full caloric intake are associated with reduced mortality and shorter ICU stays. 1

Energy Requirements

• Use indirect calorimetry (IC) to measure energy expenditure whenever possible, as it is the gold standard for determining energy needs 1, 2
• If IC is unavailable:
  • Target 1.4-1.5 times measured resting energy expenditure (REE) after the acute phase 1, 2
  • Minimum intake of 57 kcal/kg/day is required to achieve protein anabolic state 1
• Energy delivery should follow a phased approach:
  • Early phase (ICU day 1-2): Target 70-80% of estimated requirements to avoid overfeeding 1, 2
  • Late acute phase (ICU day 3-7): Gradually increase nutritional support 2
  • Recovery phase (after ICU day 7): Provide full nutritional support 2

Protein Requirements

• Target at least 1.5 g protein/kg/day to achieve a protein anabolic state 1
• Progress protein delivery as follows:
  • Early phase (ICU day 1-2): Low-dose protein (<0.8 g/kg/day) 1
  • As patient stabilizes: Increase to ≥1.2 g/kg/day 1
  • Avoid higher protein in unstable patients and those with acute kidney injury not on CRRT 1

Route of Administration

• Enteral nutrition (EN) is the preferred route of delivery 1
• Initiate EN within 72 hours of TBI, with full replacement by 7 days 1, 2
• Use gastric access as the standard approach to initiate EN 1
• For patients with gastric feeding intolerance:
  • First-line: Use prokinetic agents (IV erythromycin as first choice) 1
  • Second-line: Consider postpyloric feeding if intolerance persists despite prokinetics 1
• Consider parenteral nutrition (PN) only when:
  • Early EN is not feasible 1
  • Gastrointestinal tract discontinuity or obstruction exists 1
• Use continuous rather than bolus EN to reduce diarrhea 1

Monitoring and Management

• Monitor for insulin resistance and maintain blood glucose within target range 2
• Evaluate micronutrient levels after ICU day 5-7, especially in patients on CRRT 1
• Track delivered energy/protein and percentage of targets achieved 1
• Consider using computerized nutrition monitoring systems 1
• Assess functional recovery as the primary outcome measure 2

Special Considerations for TBI Patients

• TBI patients differ from other critically ill patients due to:

  • Modified metabolic status from medications (sedatives, analgesics, barbiturates, muscle relaxants) 1
  • Potential use of therapeutic hypothermia 1
  • Variable metabolic rates depending on level of consciousness, presence of infection, temperature, and posturing responses 1

• Caloric intake is critically important in TBI patients:

  • Every 10-kcal/kg decrease in caloric intake is associated with a 30-40% increase in mortality rates 1, 2
  • Early initiation and achieving full caloric intake correlate with shorter ICU stays 1

Common Pitfalls and Caveats

• Avoid overfeeding in the early phase as the body may not process nutrients effectively 2
• Be aware that TBI patients often have delayed gastric emptying and poor tolerance to enteral feeding, which may persist for up to 14 days post-injury 3
• Recognize that tolerance of enteral feeding is inversely related to increased intracranial pressure and severity of brain injury 3
• Predictive equations for energy requirements have limited accuracy (50%) with potential errors of up to 1000 kcal/day; use IC when possible 2
• Monitor for refeeding syndrome, particularly hypophosphatemia, when initiating nutrition 1

By following these evidence-based recommendations for nutritional management in TBI patients, clinicians can help reduce mortality, decrease infectious complications, and improve neurologic outcomes.