Trace element intakes should be revisited in burn nutrition protocols: A cohort study

Summary

Background & aims

Due to inflammatory and hypermetabolic responses and to extensive exudative trace element (TEs) losses, major burn patients have substantially increased nutritional requirements. To date, information is only available for Cu, Se, and Zn. We aimed at analyzing losses of 12 TEs and Mg through burn wound exudation and corresponding plasma concentrations during the first week after burn injury, and to evaluate the impact of current TE repletion protocols.

Methods

Burn wound exudate was collected under negative pressure in 15 adult patients burned 29 ± 20% of body surface (TBSA) for 8 days after injury. Two samples were collected daily. The TE concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS). Losses and serum concentrations were compared to intakes.

Results

For the majority of 12 TEs, the highest losses were observed on day 1, and declined thereafter. Despite Cu supplementation (4.23 mg/day) serum levels remained below reference values. Se supplements (745 μg/day) normalized and even increased serum levels to upper normal value. Despite large supplements (Zn 67.5 mg/day), serum Zn values remained below reference range. Large exudative losses of B, Br and Mg were found, as well as of Fe and I, with the latter being probably due to contamination.

Conclusion

Current nutritional Cu, Se, Zn repletion protocols in major burn patients which were based on measured exudative losses should be revised to include higher Cu and lower Se doses, as well as planned Mg administration. In burns <20% TBSA and for the other TEs the recommended parenteral nutrition TE doses appear sufficient.

Introduction

After major burns, hypermetabolic state induced by oxidative stress and extensive inflammation increases nutritional requirements. Burn patients frequently exhibit low circulating concentrations of several TEs that are explained by the combination of urinary excretion [1], fluid and micronutrient losses through burn wound exudation resulting in micronutrient deficiencies that complicate the clinical course and are, in part, responsible for infections and delayed wound healing [1]. Wound exudation was found to be a major route for TE losses in burn patients resulting in losses of 10–40% of overall body content of copper (Cu), 10% of zinc (Zn) and 10% of selenium (Se) during the first week after trauma [2], [3]. So far, only these three TEs were studied because of their particular role in wound healing [4], [5], antioxidant defense [6] and immune function [5], which are all of extreme importance in the clinical course of burns [7]. Compensation of exudative losses of these TEs through early intravenous repletion has been associated with reduced infection and Intensive Care Unit (ICU) stays, improved antioxidant status and skin local protein metabolism along with wound healing [8], [9], [10]. They were therefore included in recommendations for major burn nutrition (ESPEN guidelines 2013 [11]).

Eleven TEs are essential for the activity of multiple enzymes involved in immune function, gene expression regulation and antioxidant defense [12], but the majority of them are not measurable in clinical settings. Current nutritional supplementation of TEs for burns also considers only Cu, Se, and Zn due to a lack of investigations on other elements. Furthermore, these recommendations are based on exudative losses that were measured with simple mass spectrometry in wound exudates collected indirectly from dressings that covered the burn wounds [2], [3]. A reassessment of TE requirements in burn patients is required in order to up-date the local TE repletion protocols and to complete the recommendation for the other TEs that are currently missing in clinical practice. The present study aimed at quantifying and measuring kinetics of TE exudative losses using a new methodology with a direct and continuous collection system from burn wounds over the first week after burn injury.