RESUMEN
OBJECTIVES: Complications resulting from zinc and copper deficiency, or adverse effects from excessive zinc and copper intake should be avoided during total parenteral nutrition (TPN). This study was conducted on critically ill patients requiring TPN to determine the relationship between the zinc and copper levels of the TPN mixtures, patients' clinical progression, and changes in plasma levels of zinc, serum levels of copper, and erythrocyte levels of zinc and copper. PATIENTS AND METHODS: 29 adult critically ill patients following pancreatitis or after a major abdominal surgery were studied. Zinc and copper levels in TPN, plasmatic zinc levels, copper serum levels and erythrocyte levels of zinc and copper were determined at the onset and at the end of the treatment (5-21 days) (using Atomic Absorption Spectrometry). RESULTS: The mean+/-standard deviation (and ranges in parenthesis) of zinc and copper levels in TPN were (microg/mL): zinc: 4.2+/-1.7 (1.8 a 9.3); copper: 0.94+/-0.66 (0.1 a 3.1). Biochemical parameters at the onset and at the end of the treatment were, respectively: (microg/mL): plasmatic zinc: 80+/-45 (29-205) and 122+/-56 (37-229); erythrocyte zinc: 2,300+/-1,070 (790-5,280) and 2,160+/-920 (790-4,440); serum copper (microg/dL): 124+/-35 (62-211) and 128+/-41 (60- 238); erythrocyte copper (microg/dl): 72+/-39 (4-183) and 70+/-41 (9-156). Plasmatic and erythrocyte zinc levels did not correlated neither at the onset nor at the end of the treatment. Changes in erythrocyte zinc levels correlated with daily administered zinc (mg/d) in the parenteral nutrition (r=0.38). Serum copper and erythrocyte copper showed significant correlation at the onset (p=0.0005) and at the end of treatment (p=0.008). Changes of serum or erythrocyte copper levels showed a significant correlation with daily administered copper (r=0.31 and 0.26, respectively). CONCLUSIONS: These results show that: 1) determination of erythrocyte zinc and copper levels in these critically ill patients would help to control zinc and copper administration levels in TPN and avoid adverse effects; 2) TPN Zn levels should be less than 8.1 mg/d, and 3) TPN Cu levels higher than 1.2 mg/d would not be recommended.