How is energy metabolism supported in sepsis?

Energy Metabolism Support in Sepsis

In sepsis, energy support should be initiated early with enteral nutrition starting within 48 hours, targeting trophic/hypocaloric feeding (≤70% of caloric goals) initially, then advancing to 25-30 kcal/kg ideal body weight during recovery, while avoiding early full feeding that may worsen outcomes. 1

Initial Phase Energy Strategy (First 48-72 Hours)

Start Early Enteral Nutrition

• Begin enteral feeding within the first 48 hours of sepsis recognition, even though evidence shows no mortality difference compared to delayed feeding, as early feeding may reduce gut permeability, inflammation, and infection risk 1
• Avoid providing more than 20-25 kcal/kg ideal body weight during the acute sepsis phase, as higher caloric intake in this period has been associated with inferior outcomes 1

Trophic/Hypocaloric Approach

• Target 10-20 kcal/hr or up to 70% of standard caloric goals for at least 48 hours before titrating toward full feeds 1
• This approach shows no difference in mortality (RR 0.95% CI 0.82-1.10), infections, or ICU length of stay compared to full feeding, based on high-quality evidence from 2,665 patients 1
• The biological rationale: limiting caloric intake stimulates autophagy, a defense mechanism against intracellular organisms that may reduce infection risk 1

Protein Administration

• Administer 0.8-1.5 g/kg/day protein even during the trophic/hypocaloric phase to prevent skeletal mass loss, ventilator weaning challenges, and general weakness 1
• Protein requirements should be met regardless of caloric restriction 1

Recovery Phase Energy Strategy (After 48-72 Hours)

Advance Caloric Intake

• Increase to 25-30 kcal/kg ideal body weight during the recovery phase once patients have stabilized hemodynamically 1
• Titrate enteral feeds progressively according to gastrointestinal tolerance 1

Route of Administration

• Prioritize enteral nutrition over parenteral nutrition to preserve gut integrity, maintain intestinal permeability, and down-modulate inflammatory response 1
• If enteral nutrition is insufficient after 3 days, add parenteral nutrition up to approximately half of predicted energy needs 1

Special Populations and Caveats

Malnourished Patients (BMI <18.5)

• Exercise extreme caution: malnourished patients were excluded from most trials supporting trophic/hypocaloric feeding 1
• Consider more aggressive enteral feed titration while monitoring closely for refeeding syndrome 1
• In malnourished patients, restart energy supply slowly with stepwise increase in daily caloric intake, avoiding large carbohydrate loads 1

Patients with High Vasopressor Requirements

• Individualize the decision about withholding feeds, as current evidence did not specifically address this population 1
• Consider delaying enteral nutrition until hemodynamic stability is achieved in septic shock with significant vasopressor needs 1

Patients Not Tolerating Enteral Feeds

• Prefer trophic/hypocaloric feeding over full feeding for patients with sepsis or septic shock who cannot tolerate enteral feeds 1
• Titrate feeds over time according to patient tolerance rather than forcing full caloric goals 1

Specific Nutrient Considerations

Avoid Immune-Modulating Supplements

• Do not use omega-3 fatty acids as immune supplements in critically ill septic patients (strong recommendation, low-quality evidence) 1
• Do not use glutamine to treat sepsis and septic shock, as recent well-designed studies failed to show mortality benefit and some suggested potential harm 1

Patients with Mild Sepsis (APACHE II 10-15)

• Consider formulations enriched with arginine, nucleotides, and omega-3 fatty acids, which reduced mortality in one randomized trial 1
• Avoid these enriched formulations in severe sepsis with APACHE II >25, as mortality may be increased 1

Common Pitfalls to Avoid

• Never provide early full feeding (>70% of caloric goals in first 48 hours): intentional early underfeeding compared to early full feeding may lead to immune hyporesponsiveness and increased infectious complications 1
• Never use peptide-based formulas: they are not superior to whole protein formulas 1
• Never delay protein administration: critical illness causes loss of skeletal mass, and inadequate protein may impair ventilator weaning 1
• Never ignore refeeding syndrome risk: particularly in malnourished patients when advancing nutrition 1