Sequential evaluations of trace elements in patients receiving parenteral nutrition

Area of Science:

• Clinical Nutrition
• Trace Element Metabolism
• Critical Care Medicine

Background:

• Critically ill patients often require parenteral nutrition (PN).
• Trace elements (TEs) are essential micronutrients that must be supplied in PN.
• Maintaining adequate TE levels is crucial for patient recovery.

Purpose of the Study:

• To assess serum TE levels in critically ill patients receiving standard PN doses.
• To determine if recommended TE doses maintain stable serum concentrations over time.
• To identify TEs that may require dose adjustments in PN for this population.

Main Methods:

• Serum TE levels (zinc, iron, copper, manganese, iodine) were measured before and at 2 and 4 weeks after PN initiation.
• 46 critically ill patients receiving PN with recommended daily TE doses were studied.
• Statistical analysis compared TE levels across the three measurement time points.

Main Results:

• Serum levels of iron, copper, and manganese remained stable throughout PN.
• Significant changes were observed in serum zinc levels (p<0.001).
• Thyroid hormone levels (T3, unbound T3) also showed significant alterations, but T4 and unbound T4 did not.

Conclusions:

• Recommended PN doses for iron, copper, and manganese appear adequate for critically ill patients.
• The recommended doses of zinc and iodine may not be sufficient to maintain stable serum levels.
• Further investigation into zinc and iodine requirements in PN for critically ill patients is warranted.