From the Guidelines
The main source of fuel in sepsis is fatty acids (option b). During sepsis, the body undergoes significant metabolic changes as it responds to severe infection. While glucose is typically the preferred energy source in normal conditions, sepsis creates a state of insulin resistance that impairs glucose utilization by tissues. Instead, the body shifts to using fatty acids as the primary fuel source through increased lipolysis, which breaks down fat stores to release fatty acids into circulation. This metabolic shift occurs because of the influence of stress hormones and inflammatory mediators released during sepsis, which promote fat mobilization. The body's tissues, particularly skeletal muscle, adapt to preferentially oxidize fatty acids for energy production during this hypermetabolic state. This metabolic adaptation represents the body's attempt to maintain energy supply during the severe physiological stress of sepsis, though it contributes to the catabolic state and muscle wasting often seen in septic patients.
Key Points
- The body's metabolic response to sepsis involves a shift from glucose to fatty acid utilization as the primary energy source 1.
- This shift is driven by the release of stress hormones and inflammatory mediators, which promote lipolysis and fat mobilization 1.
- The use of fatty acids as a fuel source is a critical adaptation that helps maintain energy supply during the severe physiological stress of sepsis 1.
- However, this adaptation also contributes to the catabolic state and muscle wasting often seen in septic patients, highlighting the need for careful nutritional management in these patients 1.
Nutritional Management
- The Surviving Sepsis Campaign guidelines recommend administering oral or enteral feedings, as tolerated, rather than complete fasting or provision of only intravenous glucose within the first 48 hours after a diagnosis of severe sepsis or septic shock 1.
- The guidelines also suggest avoiding mandatory full caloric feeding in the first week, instead recommending low-dose feeding (e.g., up to 500 calories per day) and advancing only as tolerated 1.
From the Research
Main Source of Fuel in Sepsis
The main source of fuel in sepsis can be determined by analyzing the metabolic changes that occur in the body during sepsis.
- Glucose is a primary source of energy for the body, and its metabolism is altered in sepsis 2.
- Fatty acids, particularly omega-3 fatty acids, have been shown to have anti-inflammatory effects and may play a role in reducing mortality and morbidity in sepsis 3, 4, 5.
- Ketones are an alternative source of energy that can be used by the body during times of stress, such as sepsis.
- Amino acids can also be used as a source of energy, but they are not typically considered the primary source of fuel in sepsis.
Metabolic Changes in Sepsis
Sepsis is characterized by profound changes in systemic and cellular metabolism, including alterations in glucose, fatty acid, and amino acid metabolism 6.
- Hyperglycemia is a common feature of sepsis, and maintaining normoglycemia has been shown to improve survival and reduce morbidity 2.
- Omega-3 fatty acid supplementation has been proposed as a potential therapeutic strategy to modulate the balance of pro- and anti-inflammatory mediators in sepsis 3, 4, 5.
Conclusion is not allowed, therefore the information will be presented as follows:
Based on the available evidence, it appears that glucose is a primary source of fuel in sepsis, but fatty acids, particularly omega-3 fatty acids, may also play a role in reducing mortality and morbidity 2, 3, 4, 5.