Aluminum balance in intensive care patients

Aluminum (Al) is a well known contaminant of intravenous solutions. The aim of the present study was the estimation of the aluminum load in patients of an intensive care unit (ICU). 15 patients with normal renal function took part. The study period was 15 days. Al was measured in serum, 24 h-urine and 132 samples of parenterals. Daily Al doses were recorded. Al balance was calculated on the basis of the iatrogenic Al dose and renal Al excretion. Al analysis was performed by graphite furnace atomic absorption spectrometry (AAS) with Zeeman background correction under careful quality control. Solutions with Al levels >100 microg/l were: calcium salts, additives for parenteral nutrition solutions, antibiotics, acetylcysteine, triflupromazine, catecholamines and colloids. The Al content of solutions for parenteral nutrition ranged from 4.3 to 69 microg/l. Al doses amounted to 46-456 (median 119) microg/d, equivalent to 0.7 to 6.5 (median 1.7) microg/kg b.w. Renal Al excretion ranged from 10.5 to 723.1 microg/d (median 53 microg/d). These amounts partly exceeded the maximal dose (2 microg/kg b.w. per day), recommended by ASPEN/ASCN. Despite of the highly elevated renal Al excretion the median serum concentration of Al was only moderately increased (6.1 microg/l; range: <1.5 to 23.6 microg/l). However, calculations on the basis of the iatrogenic Al dose and renal Al excretion resulted in a net Al uptake (median) of 61 microg/d (maximum: 291 microg/d). Al amounts of this magnitude must be considered potentially harmful in ICU patients, especially with impaired renal function. Parenteral therapy resulted in a considerable Al dose with a positive Al balance in ICU patients. Threshold values for Al contamination of parenterally administered drugs and solutions should be established.