The lipid component of parenteral nutrition should contain a balance of fatty acids. While they are essential for membrane structure, they are also precursors of important lipid mediators. Although optimal fatty acid balance is still not defined, the emulsion should provide fatty acids with desirable biological activities and avoid providing them with excessive amounts of unfavorable characteristics. The emulsion should also provide the correct amount of omega-3 fatty acids without adding unnecessary or undesirable metabolites. In this way, a nutrient-rich lipid would improve the health of the patient.
The management of patients in ICU has many aspects. In these patients, there is an increased catabolism, anabolic resistance and mitochondrial dysfunction. Among treatments modalities, nutrition is a major role and lipids are an important and concentrated source of energy.
The answer is definitely NO.
Although all lipids yield the same amount of energy, they have different effects on inflammation, immunity, the lipid peroxidation, liver dysfunction and finally, on patient outcome.
Fatty acids are divided into three main groups. Saturated fatty acids have no double bonds in carbon chain as an example stearic acid.
Monounsaturated fatty acids have one double bond in carbon chain, a typical example is oleic acid or olive oil.
And finally, polyunsaturated fatty acids have two or more double bonds in carbon chain, as an example, linoleic acid, which has two double bonds.
An important phenomenon in the ICU patient is oxidative stress and lipid peroxidation. Oxidative stress occurs when there is an imbalance between reactive oxygen species production and antioxidant systems
Oxidative stress can be secondary to many pathologies, including infection and SIRS. The generation of free radicals result in damage to lipids, proteins and DNA.
Oleic acid has only one double bond and this makes it less prone to lipid peroxidation. In addition to that, metabolism of oleic acid does not produce eicosanoids and this renders oleic acid to be inflammatory neutral.
Let me summarize some of the basic characteristics of lipids. Soybean oil is a good source for essential fatty acids and it has pro inflammatory effects. medium chain triglycerides or MCTs are less pro inflammatory and they can be easily oxidized. Olive oil is immune neutral and resistant to lipid peroxidation. And finally, fish oil has anti inflammatory properties.
This is a nice study coming from China, which was performed in over 450 patients. The patients are divided into two groups. One group received olive oil based parenteral nutrition and the other group received so in oil based around nutrition. The results of this randomized study showed that olive oil based parenteral nutrition group was associated with significantly fewer infections when compared to soybean oil based group.
A recent meta analysis with omega three fatty acid enriched parenteral nutrition in ICU patients. This meta analysis included 24 randomized control trials, and over 1400 patients.
The authors compared the clinical outcomes of fish oil and standard parenteral nutrition group. This analysis demonstrates that fish oil or omega three fatty acids containing parenteral nutrition is associated with statistically and clinically significant improvement in patient outcomes.
When you look at this meta analysis in detail, infection rates in ICU patients decreased significantly, favoring omega three fatty acids and length of ICU stay was reduced about two days favoring again fish oils.
Suggests withholding or limiting soybean-based IV Lipid Emulsion during the first week following initiation of PN in the critically ill patient
Suggests that immune-modulating formulas not be used routinely in patients with severe sepsis.
The administration of intravenous lipid emulsions should be generally a part of PN.
High doses of omega-3 enriched enteral formulas should not be given on a routine basis.
All lipids are not same and the major difference of lipid solutions is their effect on immune system.
In the critically ill patients, soybean based IV Lipid Emulsion may interfere with immune function and may have deleterious effects.
Fish oil has anti-inflammatory properties which may be advantageous or disadvantageous depending on the condition of the patient.
Immunological/inflammatory neutrality and limitation of lipid peroxidation are the major advantages of olive oil based IV Lipid Emulsion.