Impact of Early Administration of High Protein Dose on Mortality of Critically Ill Patients

Catabolic Stress in Critically Ill Patients

During sepsis, trauma, or other severe tissue damage, catabolic stress occurs. This is a life-threatening condition that rapidly depletes protein stores in skeletal muscle.¹ Critically ill adults can lose up to 1 kg of muscle mass daily, especially during the first 5 days in the ICU.² Consequences of the loss of active body mass include prolonged mechanical ventilation, poor wound healing, muscle weakness, or risk of rehospitalizations.³⁻⁵ Additionally, critically ill patients are at risk of reduced immunity.⁶

The Importance of Protein Intake

In catabolic critical illness, proteins are the decisive macronutrient. Their amount is more important than the total energy intake.¹ Most critically ill patients receive only half of the recommended protein dose during the first week in the ICU.¹ Adequate protein intake can help in wound healing, hormonal regulation, and immune response.⁵ Higher protein doses have been shown to shorten the duration of mechanical ventilation and are associated with lower mortality.^{3, 5}

According to current ESPEN⁷ recommendations, protein intake in critically ill patients should be 1.3 g/kg/day. According to ASPEN⁸ recommendations, the recommended daily protein dose in these patients increases with higher BMI (at least 2 g/kg/day for BMI 30–40 kg/m² and at least 2.5 g/kg/day for BMI ≥ 40 kg/m²).

Evidence from Clinical Studies

In a retrospective cohort study involving 1171 critically ill patients in intensive care on mechanical ventilation, increased protein intake was associated with reduced 60-day mortality. For every 1 g of protein administered, a 1% reduction in mortality was observed.⁹

A prospective observational study with 843 patients hospitalized in the ICU showed that early administration of a high protein dose or lower energy intake at the beginning of treatment could lead to different outcomes. This study included 424 patients with excessive energy intake (defined as the ratio between energy intake and measured energy expenditure > 1.1) and 419 without excessive energy intake. Energy intake 10–20% below the recommended value during the first 4 days was associated with lower overall mortality. Lower overall mortality was also found in patients with early administration of a higher protein dose. Among patients without sepsis and excessive caloric intake (n = 419), which were mortality risk factors, mortality decreased with increasing daily protein intake: it was 37% with protein intake < 0.8 g/kg, 35% with protein intake 0.8–1.0 g/kg, 27% with protein intake 1.0–1.2 g/kg, and 19% with protein intake ≥ 1.2 g/kg (p = 0.033). In this study, protein intake did not significantly affect mortality in patients with sepsis.¹⁰

Conclusion

The prescription of parenteral nutrition, energy intake, and protein intake in critically ill patients should be based on available evidence and current recommendations while considering the individual characteristics of each patient. This can significantly influence treatment outcomes.

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