What are the nutritional requirements for patients with Acute Respiratory Distress Syndrome (ARDS)?

Nutritional Requirements for Patients with Acute Respiratory Distress Syndrome (ARDS)

Patients with ARDS should receive 20-30 kcal/kg/day with 1.2-1.5 g/kg/day of protein, and should be started on early enteral nutrition within 24-48 hours of ICU admission when hemodynamically stable. 1

Energy Requirements

Caloric Goals

• Initial phase (acute/early): 20-25 kcal/kg/day 1
• Recovery phase (anabolic): 25-30 kcal/kg/day 1
• Severely undernourished patients: Up to 25-30 kcal/kg/day 1

Implementation Strategy

• Start with lower caloric goals (12-25 kcal/kg/day) in the acute phase 1
• Gradually increase to target goals as clinical condition improves 1
• Consider indirect calorimetry for more precise assessment when available 1
• Avoid overfeeding as it may worsen outcomes and prolong mechanical ventilation 1, 2

Protein Requirements

• Standard recommendation: 1.2-1.5 g/kg/day of protein 1
• Higher requirements may be needed in hypercatabolic states 1
• Protein restriction is not recommended in ARDS patients 1

Route of Administration

Enteral Nutrition (EN)

• First choice: Start EN within 24-48 hours of ICU admission 1, 3
• Early EN is associated with improved 60-day survival and better outcomes 4, 3
• Use gastric route initially; no significant difference between gastric and jejunal feeding 1
• Consider post-pyloric feeding in patients with high aspiration risk 1

Parenteral Nutrition (PN)

• Use only when EN is contraindicated or insufficient 1
• Avoid additional PN in patients who tolerate EN and can meet approximately target values 1
• Consider careful PN in patients intolerant to EN at a level equal to but not exceeding nutritional needs 1

Special Nutritional Formulations

Immune-Modulating Formulas

• Formulas enriched with omega-3 fatty acids (EPA), antioxidants, and gamma-linolenic acid (GLA) are beneficial specifically for ARDS patients 1, 5
• These formulas may improve oxygenation and reduce ICU length of stay 5
• However, evidence regarding mortality benefit is mixed 6, 5

Glutamine Supplementation

• Consider glutamine supplementation for trauma patients 1
• Insufficient data to support glutamine supplementation in all critically ill patients 1

Monitoring and Adjustments

Monitoring Parameters

• Regular assessment of tolerance to EN (gastric residuals, abdominal distension)
• Monitor electrolytes, especially when initiating nutrition (risk of refeeding syndrome) 1
• Track blood glucose levels with target of 140-180 mg/dL 1

Nutritional Assessment

• Use Nutrition Risk in the Critically Ill (NUTRIC) score to identify high-risk patients 1
• Serial monitoring of anthropometric and laboratory parameters 2

Special Considerations

Prone Positioning

• Early EN should be continued in patients managed in prone position 1

ECMO Patients

• Early EN should be performed in patients receiving ECMO 1

Non-intubated ARDS Patients

• For non-intubated patients not reaching energy targets with oral diet, consider oral nutritional supplements first, then EN 1
• In patients with dysphagia, use texture-adapted food; if swallowing is unsafe, use EN 1

Common Pitfalls and Practical Tips

• Underfeeding: Inadequate calorie delivery (≤50% of recommended value) is associated with higher mortality 2
• Overfeeding: Can worsen respiratory function by increasing CO₂ production
• Delayed nutrition: Avoid delays in starting nutrition; implement protocols to ensure early initiation 3
• Refeeding syndrome: Monitor for electrolyte abnormalities (potassium, magnesium, phosphorus) when initiating nutrition in malnourished patients 1

Early and adequate nutritional support should be considered a primary therapy rather than just supportive care in ARDS management, as it directly impacts patient outcomes including mortality, duration of mechanical ventilation, and ICU length of stay 4, 2, 3.