Impact of Intravenous Lipid Emulsions Containing Fish Oil on Clinical Outcomes in Critically Ill Surgical Patients: A Literature Review

n-3 Polyunsaturated Fatty Acid Supplementation Affects Oxidative Stress Marker Levels in Patients with Type II Intestinal Failure: A Randomized Double Blind Trial

Type II intestinal failure (IF-II) is a condition in which the gastrointestinal tract is compromised. Liver complications may occur because of the pathology and/or prolonged use of parenteral nutrition (PN); oxidative stress has been implicated as one of the causes. Lipid emulsions containing n-3 polyunsaturated fatty acids (PUFAs) have been proposed for the treatment. We aimed to evaluate the effect of 7-day n-3 PUFA supplementation on oxidative stress in IF-II patients receiving PN. This was a randomized, controlled, double-blinded, pilot trial of adult patients with IF-II, receiving either conventional PN (control) or PN enriched with n-3 PUFAs (intervention). Twenty patients were included (14 men, 49 ± 16.9 years), with the ANCOVA analysis the glucose (p = 0.003), and direct bilirubin (p = 0.001) levels reduced; whereas the high-density lipoprotein cholesterol (HDL-C) increased (p = 0.017). In the random-effect linear regression analysis, a reduction (p < 0.0001) in the malondialdehyde (MDA) level was found in the intervention group when the covariables age, HDL-C level, and alanine aminotransferase activity were considered. After 1 week of PN supplementation with n-3 PUFAs, the marker levels of some oxidative stress, blood lipids, and hepatic biomarkers improved in patients with IF-II.

The role of omega-3 polyunsaturated fatty acids in the intensive care unit

PURPOSE OF REVIEW

This review provides an update on the actions of omega-3 polyunsaturated fatty acids (PUFAs) and presents the most recent findings from trials in patients in the intensive care unit (ICU) setting including relevant meta-analyses. Many specialized pro-resolving mediators (SPMs) are produced from bioactive omega-3 PUFAs and may explain many of the beneficial effects of omega-3 PUFAs, although other mechanisms of action of omega-3 PUFAs are being uncovered.

RECENT FINDINGS

SPMs resolve inflammation, promote healing and support antiinfection activities of the immune system. Since publication of the ESPEN guidelines, numerous studies further support the use of omega-3 PUFAs. Recent meta-analyses favor the inclusion of omega-3 PUFAs in nutrition support of patients with acute respiratory distress syndrome or sepsis. Recent trials indicate that omega-3 PUFAs may protect against delirium and liver dysfunction in patients in the ICU, although effects on muscle loss are unclear and require further investigation. Critical illness may alter omega-3 PUFA turnover. There has been significant discussion about the potential for omega-3 PUFAs and SPMs in treatment of coronavirus disease 2019.

SUMMARY

Evidence for benefits of omega-3 PUFAs in the ICU setting has strengthened through new trials and meta-analyses. Nevertheless, better quality trials are still needed. SPMs may explain many of the benefits of omega-3 PUFAs.

The emerging roles of next-generation metabolomics in critical care nutrition

Critical illness leads to millions of deaths worldwide each year, with a significant surge due to the COVID-19 pandemic. Patients with critical illness are frequently associated with systemic metabolic disorders and malnutrition. The idea of intervention for critically ill patients through enteral and parenteral nutrition has been paid more and more attention gradually. However, current nutritional therapies focus on evidence-based practice, and there have been lacking holistic approaches for nutritional support assessment. Metabolomics is a well-established omics technique in system biology that enables comprehensive profiling of metabolites in a biological system and thus provides the underlying information expressed and modulated by all other omics layers. In recent years, with the development of high-resolution and accurate mass spectrometry, metabolomics entered a new "generation", promoting its broader applications in critical care nutrition. In this review, we first described the technological development and milestones of next-generation metabolomics in the past 20 years. We then discussed the emerging roles of next-generation metabolomics in advancing our understanding of critical care nutrition, such as nutritional deficiency risk evaluation, metabolic mechanisms of nutritional therapies, and novel nutrition target identification.

Does the use of fish oil-based lipid emulsion in the clinical setting of total parenteral nutrition and lipid rescue therapy interfere with common laboratory analytes on Roche Cobas 6000?

BACKGROUND

Lipaemic interference on automated analysers has been widely studied using soy-based emulsion such as Intralipid. Due to the greater adoption of fish oil-based lipid emulsion for total parenteral nutrition in view of improved clinical outcomes, we seek to characterize the optical properties of SMOFlipid 20% (Fresenius Kabi, Bad Homburg, Germany), a fish oil-based emulsion, on the Roche Cobas 6000 chemistry analyser (Roche Diagnostic, Basel, Switzerland).

METHOD

Various amounts of SMOFlipid were spiked into pooled serums. We plotted Roche Cobas Serum Index Gen.2 Lipaemia Index (L-index) against the amount of SMOFlipid added. We then studied the interference thresholds for aspartate aminotransferase, alanine aminotransferase, albumin and renal panel analytes using SMOFlipid. We subjected five levels of spiked lipaemia to high-speed centrifugation and analysed the specimens pre- and post-centrifugation. To postulate whether fish oil-based lipid emulsion interferes with laboratory results in the clinical setting, we calculated concentrations of SMOFlipid post-lipid rescue therapy and steady-state concentration of a typical total parenteral nutrition regime using pharmacokinetic principles.

RESULTS

SMOFlipid optical behaviour is similar to Intralipid using the Serum Index Gen.2 L-index, with 1 mg/dL of SMOFlipid representing 1 unit of L-index. Manufacturer-stated interference thresholds are accurate for alanine aminotransferase, aspartate aminotransferase, albumin, urea and creatinine. High-speed centrifugation at 60 min 21,100g facilitates the removal of fish oil-based SMOFlipid.

CONCLUSION

Based on the interference thresholds we verified and pharmacokinetics parameters provided by SMOFlipid manufacturer, total parenteral nutrition may not interfere with chemistry analytes given sufficient clearance, but lipid rescue therapy will interfere. Further studies assessing lipaemic interference on immunoassays are needed.

Infusion time for fish oil-containing parenteral emulsions in surgery: A study on ω-3 fatty acid dynamics in rats

OBJECTIVES

The aim of this study was to contribute to the design of specialized parenteral nutrition protocols in surgery by evaluating the dynamics of polyunsaturated fatty acid (PUFA) concentrations in different body pools after the infusion of fish oil-containing lipid emulsion (FOLE) in rats that had undergone surgical central venous catheterization (CVC).

METHODS

After 5-d adaptation in metabolic cages, 78 male Lewis rats (300-450 g) fed a standard diet were sacrificed (baseline control) or had only CVC (surgical control) or also received a 72-h infusion of a parenteral lipid emulsion with or without fish oil. The catheterized animals were sacrificed 0 (T0), 2 (T2), 6 (T6), and 12 h (T12) after the infusion ended. Gas chromatography was used to determine the concentrations of eicosapentaenoic (EPA), docosahexaenoic (DHA), and arachidonic (ARA) acids and the ω-3 to ω-6 ratio in plasma, liver, and blood leukocytes. Kruskal-Wallis and Wilcoxon tests were applied to plasma and liver data and descriptive analysis to leukocyte data.

RESULTS

Plasma, liver, and leukocytes exhibited almost undetectable EPA and DHA and detectable ARA concentrations at baseline. Immediately after FOLE infusion (T0), these PUFAs changed in all pools, resulting in a higher ratio of ω-3 to ω-6 compared with rats with no FOLE infusion (P < 0.05). All these changes decreased over time, with residual effects remaining until T6 in plasma, T12 in liver, and only until T2 in leukocytes.

CONCLUSION

Data from this study suggest that ω-3 PUFAs are cleared early after the end of FOLE infusion, mainly in leukocytes. This should be considered when FOLEs are applied for immunomodulatory purposes in surgery.

Omega-3 fatty acid-containing parenteral nutrition in ICU patients: systematic review with meta-analysis and cost-effectiveness analysis

Background

Omega-3 (ω-3) fatty acid (FA)-containing parenteral nutrition (PN) is associated with significant improvements in patient outcomes compared with standard PN regimens without ω-3 FA lipid emulsions. Here, we evaluate the impact of ω-3 FA-containing PN versus standard PN on clinical outcomes and costs in adult intensive care unit (ICU) patients using a meta-analysis and subsequent cost-effectiveness analysis from the perspective of a hospital operating in five European countries (France, Germany, Italy, Spain, UK) and the US.

Methods

We present a pharmacoeconomic simulation based on a systematic literature review with meta-analysis. Clinical outcomes and costs comparing ω-3 FA-containing PN with standard PN were evaluated in adult ICU patients eligible to receive PN covering at least 70% of their total energy requirements and in the subgroup of critically ill ICU patients (mean ICU stay > 48 h). The meta-analysis with the co-primary outcomes of infection rate and mortality rate was based on randomized controlled trial data retrieved via a systematic literature review; resulting efficacy data were subsequently employed in country-specific cost-effectiveness analyses.

Results

In adult ICU patients, ω-3 FA-containing PN versus standard PN was associated with significant reductions in the relative risk (RR) of infection (RR 0.62; 95% CI 0.45, 0.86; p = 0.004), hospital length of stay (HLOS) (− 3.05 days; 95% CI − 5.03, − 1.07; p = 0.003) and ICU length of stay (LOS) (− 1.89 days; 95% CI − 3.33, − 0.45; p = 0.01). In critically ill ICU patients, ω-3 FA-containing PN was associated with similar reductions in infection rates (RR 0.65; 95% CI 0.46, 0.94; p = 0.02), HLOS (− 3.98 days; 95% CI − 6.90, − 1.06; p = 0.008) and ICU LOS (− 2.14 days; 95% CI − 3.89, − 0.40; p = 0.02). Overall hospital episode costs were reduced in all six countries using ω-3 FA-containing PN compared to standard PN, ranging from €-3156 ± 1404 in Spain to €-9586 ± 4157 in the US.

Conclusion

These analyses demonstrate that ω-3 FA-containing PN is associated with statistically and clinically significant improvement in patient outcomes. Its use is also predicted to yield cost savings compared to standard PN, rendering ω-3 FA-containing PN an attractive cost-saving alternative across different health care systems.

Study registration

PROSPERO CRD42019129311.

Cost-Effectiveness of Parenteral Nutrition Containing ω-3 Fatty Acids in Hospitalized Adult Patients From 5 European Countries and the US

Background

ω‐3 Fatty acid (FA)–containing parenteral nutrition (PN) is associated with improvements in patient outcomes and with reductions in hospital length of stay (HLOS) vs standard PN regimens (containing non–ω‐3 FA lipid emulsions). We present a cost‐effectiveness analysis of ω‐3 FA–containing PN vs standard PN in 5 European countries (France, Germany, Italy, Spain, UK) and the US.

Methods

This pharmacoeconomic model was based on estimates of ω‐3 efficacy reported in a recent meta‐analysis and data from country‐specific sources. It utilized a probabilistic discrete event simulation model to compare ω‐3 FA–containing PN with standard PN in a population of critically ill and general ward patients. The influence of model parameters was evaluated using probabilistic and deterministic sensitivity analyses.

Results

Overall costs were reduced with ω‐3 FA–containing PN in all 6 countries compared with standard PN, ranging from €1741 (±€1284) in Italy to €5576 (±€4193) in the US. Expenses for infections and HLOS were lower in all countries for ω‐3 FA–containing PN vs standard PN, with the largest cost differences for both in the US (infection: €825 ± €4001; HLOS: €4879 ± €1208) and the smallest savings in the UK for infections and in Spain for HLOS (€63 ± €426 and €1636 ± €372, respectively).

Conclusion

This cost‐effectiveness analysis in 6 countries demonstrates that the superior clinical efficacy of ω‐3 FA–containing PN translates into significant decreases in mean treatment cost, rendering it an attractive cost‐saving alternative to standard PN across different healthcare systems.

Fish Oil Enriched Intravenous Lipid Emulsions Reduce Triglyceride Levels in Non-Critically Ill Patients with TPN and Type 2 Diabetes. A Post-Hoc Analysis of the INSUPAR Study

There are no studies that have specifically assessed the role of intravenous lipid emulsions (ILE) enriched with fish oil in people with diabetes receiving total parenteral nutrition (TPN). The objective of this study was to assess the metabolic control (glycemic and lipid) and in-hospital complications that occurred in non-critically ill inpatients with TPN and type 2 diabetes with regard to the use of fish oil emulsions compared with other ILEs. We performed a post-hoc analysis of the Insulin in Parenteral Nutrition (INSUPAR) trial that included patients who started with TPN for any cause and that would predictably continue with TPN for at least five days. The study included 161 patients who started with TPN for any cause. There were 80 patients (49.7%) on fish oil enriched ILEs and 81 patients (50.3%) on other ILEs. We found significant decreases in triglyceride levels in the fish oil group compared to the other patients. We did not find any differences in glucose metabolic control: mean capillary glucose, glycemic variability, and insulin dose, except in the number of mild hypoglycemic events that was significantly higher in the fish oil group. We did not observe any differences in other metabolic, liver or infectious complications, in-hospital length of stay or mortality.

Diabetic Rat Hearts Show More Favorable Metabolic Adaptation to Omegaven Containing High Amounts of n3 Fatty Acids Than Intralipid Containing n6 Fatty Acids

BACKGROUND

While Omegaven, an omega-3 (n3) fatty acid-based lipid emulsion, fosters insulin signaling in healthy hearts, it is unknown whether beneficial metabolic effects occur in insulin-resistant diabetic hearts.

METHODS

Diabetic hearts from fructose-fed Sprague-Dawley rats were perfused in the working mode for 90 minutes in the presence of 11 mM glucose and 1.2 mM palmitate bound to albumin, the first 30 minutes without insulin followed by 60 minutes with insulin (50 mU/L). Hearts were randomly allocated to Intralipid (25 and 100 µM), Omegaven (25 and 100 µM), or no emulsion (insulin alone) for 60 minutes. Glycolysis, glycogen synthesis, and glucose oxidation were measured with the radioactive tracers [5-H]glucose and [U-C]glucose. Central carbon metabolites, acyl-coenzyme A species (acyl-CoAs), ketoacids, purines, phosphocreatine, acylcarnitines, and acyl composition of phospholipids were measured with mass spectrometry.

RESULTS

Diabetic hearts showed no response to insulin with regard to glycolytic flux, consistent with insulin resistance. Addition of either lipid emulsion did not alter this response but unexpectedly increased glucose oxidation (ratio of treatment/baseline, ie, fold change): no insulin 1.3 (0.3) [mean (standard deviation)], insulin alone 1.4 (0.4), insulin + 25 µM Intralipid 1.8 (0.5), insulin + 100 µM Intralipid 2.2 (0.4), P < .001; no insulin 1.3 (0.3), insulin alone 1.4 (0.4), insulin + 25 µM Omegaven 2.3 (0.5) insulin + 100 µM Omegaven 1.9 (0.4), P < .001. Intralipid treatment led to accumulation of acylcarnitines as a result of the released linoleic acid (C18:2-n6) and enhanced its integration into phospholipids, consistent with incomplete or impaired β-oxidation necessitating a compensatory increase in glucose oxidation. Accumulation of acylcarnitines was also associated with a higher nicotinamide adenine dinucleotide reduced/oxidized (NADH/NAD) ratio, which inhibited pyruvate dehydrogenase (PDH), and resulted in excess lactate production. In contrast, Omegaven-treated hearts showed no acylcarnitine accumulation, low malonyl-CoA concentrations consistent with activated β-oxidation, and elevated PDH activity and glucose oxidation, together indicative of a higher metabolic rate possibly by substrate cycling.

CONCLUSIONS

Omegaven is the preferred lipid emulsion for insulin-resistant diabetic hearts.

Clinical Nutrition of Critically Ill Patients in the Context of the Latest ESPEN Guidelines

The group of patients most frequently in need of nutritional support are intensive care patients. This year (i.e., 2019), new European Society for Clinical Nutrition and Metabolism (ESPEN) guidelines of clinical nutrition in intensive care were published, updating and gathering current knowledge on the subject of this group of patients. Planning the right nutritional intervention is often a challenging task involving the necessity of the choice of the enteral nutrition (EN) or parenteral nutrition (PN) route of administration, time of initiation, energy demand, amino acid content and demand as well as the use of immunomodulatory nutrition. The aim of this study was to specify and discuss the basic aspects of the clinical nutrition of critically ill patients recommended by ESPEN guidelines. Clinical nutrition in intensive care seems to be the best-studied type of nutritional intervention. However, meta-analyses and clinical studies comparing EN and PN and their impact on the prognosis of the intensive care patients showed ambiguous results. The nutritional interventions, starting with EN, should be initiated within 24-48 h whereas PN, if recommended, should be implemented within 3-7 days. The recommended method of calculation of the energy demand is indirect calorimetry, however, there are also validated equations used worldwide in everyday practice. The recommended protein intake in this group of patients and the results of insufficient or too high supply was addressed. In light of the concept of immunomodulatory nutrition, the use of appropriate amino acid solutions and lipid emulsion that can bring a positive effect on the modulation of the immune response was discussed.