Energy cost of fever in children on total parenteral nutrition

Area of Science:

• Pediatric critical care
• Metabolic research
• Nutritional science

Background:

• Children receiving total parenteral nutrition (TPN) may experience altered metabolic states.
• Fever is a common physiological response to infection or inflammation.
• Understanding metabolic changes during fever is crucial for optimizing nutritional support.

Purpose of the Study:

• To quantify the impact of fever on energy expenditure (EE) and respiratory quotient (RQ) in pediatric patients undergoing TPN.
• To determine the relationship between body temperature and EE during febrile episodes.
• To assess changes in nitrogen excretion associated with fever in this population.

Main Methods:

• Indirect calorimetry was used to measure EE over 3-hour periods in ten children (aged 1-16 years) with TPN.
• EE and RQ were recorded during both febrile (38.9 +/- 0.5°C) and afebrile conditions, with controlled nutritional intake and ambient temperature.
• Urinary nitrogen excretion was measured during febrile and afebrile phases.

Main Results:

• Energy expenditure (EE) was significantly higher during the febrile phase (2.13 +/- 0.48 kcal/kg/h) compared to the afebrile phase (1.78 +/- 0.42 kcal/kg/h; P < 0.01).
• Increased EE strongly correlated with body temperature (r = 0.92, P < 0.001), indicating a 16.2% increase in EE per degree Celsius rise in temperature.
• Urinary nitrogen excretion was significantly elevated during the febrile phase (P < 0.02), while RQ did not show significant differences between phases.

Conclusions:

• Fever induces a hypermetabolic state in children receiving TPN, characterized by significantly increased energy expenditure.
• The rise in EE during fever is directly proportional to the elevation in body temperature.
• Increased EE and nitrogen excretion during fever highlight the heightened metabolic demands and need for adjusted nutritional support in febrile pediatric TPN patients.