Micronutrients in Parenteral Nutrition in Adult Patients – Current Issues and Consensus

Introduction

Although the importance of micronutrients has long been known, the administration of vitamins and trace elements along with parenteral nutrition has several shortcomings in practice. The material prepared by a multidisciplinary team of experts aims to shed light on some ambiguities or frequent deficiencies in the prescription and administration of vitamins A, D, E, K, B, and C, as well as trace elements Cu, I, Fe, Se, Zn, Cr, Mn, Mo.

Micronutrients are not reserved only for patients with parenteral nutrition

First and foremost, it is necessary to state that the administration of micronutrients is not exclusively tied to the administration of parenteral nutrition. Micronutrients are also needed in situations such as complicated wound healing, muscle weakness, immune disorders, or in persons at risk of malnutrition. The prevention of the development of micronutrient deficiencies is their timely administration in the acute phase of illness and the development of inflammatory processes, during which the redistribution of micronutrients in the organism is influenced by pro-inflammatory cytokines. The reduction in serum concentration, which occurs to a degree dependent on the severity of the inflammation, requires the concurrent determination of C-reactive protein (CRP) levels. Joint evaluation of micronutrient levels and CRP is essential for the correct interpretation of results and determination of the course of action.

Assessment of micronutrient concentration should not be done in isolation

Reduced values, for example in vitamins A, C, E, and D and trace elements Fe, Se, Zn, Mn, and Mo, do not automatically signify a deficiency. Their redistribution and increased consumption can indicate a correctly ongoing adaptation process to a critical condition. Conversely, vitamins B₁, B₂, and B₁₂ do not respond significantly to inflammatory processes and thus reflect a real deficiency. Distinguishing whether a deficiency or a response to inflammation is really at play can sometimes be very challenging. Therefore, micronutrient concentrations should always be assessed together with other indicators, such as CRP.

When assessing nutritional status concerning micronutrients, it is also appropriate to consider clinical symptoms that may indicate abnormalities in micronutrient concentrations. Monitoring their levels is essential after dosage adjustments, and with long-term parenteral nutrition, the frequency of checks is usually left to the clinical judgment of the physician.

Consensus of professional societies

International professional societies (ASPEN, AuSPEN, and ESPEN) highlight several fundamental points concerning micronutrients and parenteral nutrition (PN) in their recommendations:

• Micronutrients are a crucial component of PN, and without them, PN would be metabolically inadequate. Micronutrients should be part of the nutrition from the first day of PN administration until its termination.
• The prescription of micronutrients must always be tailored to the individual needs of the patient.
• Repeated monitoring of micronutrient levels is an essential part of care for patients on long-term PN.
• Professional societies recommend thorough education of physicians in the field of PN to ensure that they can timely, correctly, and safely meet the complete nutritional needs of patients.

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Source: Blaauw R., Osland E., Sriram K. et al. Parenteral provision of micronutrients to adult patients: an expert consensus paper. JPEN J Parenter Enteral Nutr 2019; 43 (Suppl. 1): S5–S23, doi:10.1002/jpen.1525.