Relationship between copper doses in parenteral nutrition mixtures, serum copper, erythrocyte copper levels, ceruloplasmin and C-reactive protein, in critically ill patients

Abstract

Background and aims: There is no consensus on the recommended amounts of copper to be administered to critically ill patients on parenteral nutrition, as requirements are variable and very difficult to determine in different disease states. The objective of this study was to assess copper status of critically ill patients on total parenteral nutrition in order to prevent inadequate copper administration. Methods: The study comprised adult patients (20 males and 10 females) requiring total parenteral nutrition for 4e21 days, because of pancreatitis (n ¼ 5) or after major abdominal surgery (n ¼ 25). Parenteral nutrition was discontinued when the patient tolerated enteral or oral feeding. The following parameters were determined throughout the study (4e21 days): total copper administered by parenteral nutrition, serum copper, erythrocyte copper (Atomic Absorption Spectrometry); serum ceruloplasmin (Ferroxidase activity) and C-reactive protein levels (Immunoturbidimetry, Latex HS). Results: Total copper administered in parenteral nutrition ranged between 0.03 and 3.8 mg/d, and was higher than prescribed amounts due to copper contamination of individual components. The amount of copper given in parenteral nutrition correlated with changes in erythrocyte copper, but not with changes in serum copper, ceruloplasmin, or C-reactive protein. Conclusions: Variations in erythrocyte copper levels showed significant correlation with the amount of copper administered daily in parenteral nutrition mixtures, and this biochemical indicator could be useful to monitor copper deficiency or excess in patients on parenteral nutrition. It is noteworthy that copper delivery above 1.2 mg/d was frequent and prompts such monitoring.