Selenium nutriture in total parenteral nutrition: intake levels

Quantitative Assessment of Trace-Element Contamination in Parenteral Nutrition Components

BACKGROUND

Trace-element contamination of contemporary parenteral nutrition (PN) components exists in unknown quantities and, in combination with excessive amounts of certain trace elements provided in commercially available adult, pediatric, and neonatal multitrace-element (MTE) products, could result in eventual accumulation and toxicity. This study aims to quantify trace-element contamination in components used for PN compounding to further inform recommendations for MTE product reformulation and individualized trace-element prescribing in PN.

METHODS

A total of 32 unique components (65 products) available for PN compounding were tested for manganese, chromium, selenium, zinc, and copper contamination, utilizing inductively coupled plasma mass spectrometry. Theoretical adult, pediatric, and neonatal PNs were formulated to assess the impact of macronutrient and micronutrient component doses on PN trace-element contamination.

RESULTS

Trace-element contamination was detected in 24 (75%) components tested. Chromium and manganese were common, present in 65.6% and 51.5% of all components, respectively. Eight components did not contain detectable trace-element contamination, most notably sterile water, concentrated dextrose, and lipid emulsion. Manganese contamination in theoretical adult, pediatric, and neonatal PN was 25.18, 9.92, and 1.37 µg, respectively. Chromium contamination was 4.85, 1.5, and 0.28 µg, respectively.

CONCLUSION

Trace-element contamination was prevalent in components used to compound PN. Our findings support reformulation of adult, pediatric, and neonatal manufactured MTE products to eliminate chromium, decrease manganese, and supply full daily physiologic requirements of selenium, zinc, and copper. Future study is needed to assess the additional contamination that could occur through the compounding and storage processes.

A.S.P.E.N. clinical guidelines: parenteral nutrition ordering, order review, compounding, labeling, and dispensing

BACKGROUND

Parenteral nutrition (PN) is a high-alert medication available for patient care within a complex clinical process. Beyond application of best practice recommendations to guide safe use and optimize clinical outcome, several issues are better addressed through evidence-based policies, procedures, and practices. This document provides evidence-based guidance for clinical practices involving PN prescribing, order review, and preparation.

METHOD

A systematic review of the best available evidence was used by an expert work group to answer a series of questions about PN prescribing, order review, compounding, labeling, and dispensing. Concepts from the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) format were applied as appropriate. The specific clinical guideline recommendations were developed using consensus prior to review and approval by the American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) Board of Directors. The following questions were addressed: (1) Does education of prescribers improve PN ordering? (2) What is the maximum safe osmolarity of PN admixtures intended for peripheral vein administration? (3) What are the appropriate calcium intake and calcium-phosphate ratios in PN for optimal neonatal bone mineralization? (4) What are the clinical advantages or disadvantages of commercially available premade ("premixed") multichambered PN formulations compared with traditional/customized PN formulations? (5) What are the clinical (infection, catheter occlusion) advantages or disadvantages of 2-in-1 compared with 3-in-1 PN admixtures? (6) What macronutrient dosing limits are expected to provide for the most stable 3-in-1 admixtures? (7) What are the most appropriate recommendations for optimizing calcium (gluconate) and (Na- or K-) phosphate compatibility in PN admixtures? (8) What micronutrient contamination is present in parenteral stock solutions currently used to compound PN admixtures? (9) Is it safe to use the PN admixture as a vehicle for non-nutrient medication delivery? (10) Should heparin be included in the PN admixture to reduce the risk of central vein thrombosis? (11) What methods of repackaging intravenous fat emulsion (IVFE) into smaller patient-specific volumes are safe? (12) What beyond-use date should be used for (a) IVFE dispensed for separate infusion in the original container and (b) repackaged IVFE?

A.S.P.E.N. position paper: recommendations for changes in commercially available parenteral multivitamin and multi-trace element products

The parenteral multivitamin preparations that are commercially available in the United States (U.S.) meet the requirements for most patients who receive parenteral nutrition (PN). However, a separate parenteral vitamin D preparation (cholecalciferol or ergocalciferol) should be made available for treatment of patients with vitamin D deficiency unresponsive to oral vitamin D supplementation. Carnitine is commercially available and should be routinely added to neonatal PN formulations. Choline should also be routinely added to adult and pediatric PN formulations; however, a commercially available parenteral product needs to be developed. The parenteral multi-trace element (TE) preparations that are commercially available in the U.S. require significant modifications. Single-entity trace element products can be used to meet individual patient needs when the multiple-element products are inappropriate (see Summary/A.S.P.E.N. Recommendations section for details of these proposed modifications).

Trace element contamination of total parenteral nutrition. 1. Contribution of component solutions

BACKGROUND

Trace elements have been shown to contaminate total parenteral nutrition (TPN) solutions.

METHODS

This study used the multi-elemental technology of inductively coupled plasma-mass spectrometry to demonstrate the extent to which trace elements were present in amounts above (ie, as contaminants) or below expected levels in eight TPN component solutions.

RESULTS

Of the 66 trace elements scanned, there were 12 trace element contaminants in amounts >1 microg/L (zinc, copper, manganese, chromium, selenium, boron, aluminum, titanium, barium, vanadium, arsenic, and strontium) in the eight component solutions studied. Trace element contaminants were present in all solutions, and different trace elements contaminated the solutions at various concentrations. Component solutions of amino acid, potassium chloride, calcium gluconate, and sodium chloride contained the greatest numbers of trace element contaminants, whereas the lowest numbers were present in sterile water and magnesium sulfate. Interlot and intermanufacturer variations were apparent. Measured concentrations of trace elements in the multi-trace element additive solution also were higher than the labeled values. A comparison of the amounts of contaminated trace elements delivered by a typical TPN mixture relative to the amounts typically absorbed by the gastrointestinal tract indicates that the inadvertent delivery of trace elements from contaminated TPN solutions may be substantial.

CONCLUSIONS

All eight components tested were contaminated with trace elements not intended to be present in the product, and similarly, the multi-trace element component contained trace elements either above or below that which the label claimed.

Dietary selenium intake in Belgium for different population groups at risk for deficiency

An estimation of the dietary selenium intake in different population groups in Belgium has been carried out. 24 h duplicate meals and food consumption statistics combined with concentration levels in different foods, as determined by hydride generation atomic absorption spectrometry, are used. Dietary intake of selenium is low to very low, especially for vegetarians (12.7 +/- 9.1 micrograms) and patients on long-term total parenteral nutrition (1.2 +/- 0.8 microgram). The different intakes are discussed and compared with intakes published for other countries, while the importance of bioavailability of the selenium in food in the risk of deficiency is stressed.

Concentration of selenium in plasma and erythrocytes during total parenteral nutrition in Crohn's disease

Plasma- and erythrocyte-selenium concentrations were determined in five consecutive patients with Crohn's disease given preoperative total parenteral nutrition - nil per os - for a mean period of 34 days per patient. No blood components were administered during the total parenteral nutrition. Before the total parenteral nutrition the plasma-selenium level and, to a less extent, the erythrocyte-selenium levels were below the reference values. After three weeks of total parenteral nutrition both concentrations had fallen. There were, however, clinical and biochemical signs of improvement during the total parenteral nutrition, as indicated by an increase in body weight, P-albumin and P-transferrin. In one female patient given 39 days of preoperative total parenteral nutrition containing 0.06 mumol (5 micrograms) selenium per 24 h the decreasing levels of plasma-selenium and erythrocyte-selenium were both correlated to the duration of the total parenteral nutrition (r = 0.87 and 0.96, respectively). The results suggest that total parenteral nutrition patients may be at risk for selenium deficiency, and that a supplementary administration of selenium via total parenteral nutrition may be required.

Selenium status of infants on nutritional support

We investigated the selenium status of 5 infants while on nutritional support. After 4 weeks of parenteral nutrition a significant fall in plasma selenium concentrations was observed (mean +/- SD: 0.8 +/- 0.5 micrograms/dl; normal for this age: 3.6 +/- 0.9 micrograms/dl). In 1 infant the decline in selenium value occurred simultaneously with a transient rise in transaminases. A parallel but delayed decrease in red blood cell-glutathione peroxidase activity was seen in 3 patients. After reintroduction of enteral foods, the selenium levels increased progressively to and reached control values after 6 weeks, 4 and 5 months respectively in 3 patients, suggesting that the selenium requirement on TPN was not met. We consider it essential to provide longterm TPN patients with physiological amounts of selenium in order to prevent the progressive development of a deficiency state.

Trace metal abnormalities in adults during hyperalimentation

Trace metal deficiencies are now a well-documented complication of total parenteral nutrition (TPN). Zinc deficiency may present in a variety of ways including acrodermatitis skin lesions, impaired immunity, poor growth or impaired wound healing, and mental disturbances. Copper deficiency presents a more uniform picture of hematologic abnormalities, usually anemia with leukopenia and neutropenia. Chromium and selenium deficiencies occur much less frequently, but well-documented cases have been reported. We currently recommended regular monitoring and supplementation of these four trace metals during TPN administration. This article describes the clinical abnormalities that may develop when deficiencies of trace metals occur during TPN administration, and we present recommendations for trace metal supplementation during TPN administration.

Selenium supplementation in total parenteral nutrition

Four adult patients with very low plasma selenium (Se) levels ( less than or equal to 1.5 microgram/100 ml) were given Se supplements while receiving total parenteral nutrition. A comparison was made using the compounds selenomethionine and sodium selenite given either intravenously or by mouth. Urinary excretion and Se plasma responses differed, and indicated that selenomethionine retention was greater. However, the incorporation of Se into the erythrocyte and its enzyme glutathione peroxidase was unpredictable and delayed and was not a good indicator of supplement response. No deleterious effects of supplements were observed. Se supplements are indicated especially in patients with a high risk of developing low Se levels and are best monitored by plasma Se levels.