Short report: plasma aluminium concentration and 24-hour urinary aluminium excretion before, during and after treatment with sucralfate

Aluminum load in ICU patients during stress ulcer prophylaxis

BACKGROUND

Accumulating evidence has linked high aluminum (Al) levels with toxicity and disease. Our objective was to evaluate the Al exposure of ICU patients receiving stress ulcer prophylaxis with sucralfate and ranitidine.

METHODS

Within a large prospective, randomized study, a subgroup of 30 critically ill, renally intact patients on prolonged mechanical ventilation who were being treated in intensive care units (ICU) of a university hospital were allocated to two prophylaxis subgroups: enteral sucralfate, 1 g six times daily by gastric tube (n=15), or intravenous ranitidine, 200 mg daily by 24-h continuous intravenous infusion (n=15). The Al content of large and small-volume parenterals was measured and Al intake calculated for each patient and day. Aluminum levels in serum and 24-h urine were monitored every 2 days during the 16-day observation period (days 0-15).

RESULTS

Mean daily parenteral Al exposure ranged from 101.3 to 158.7 mug/day for sucralfate and ranitidine patients, respectively. In both groups, Al serum levels increased from baseline on days 1-13 and on days 3-7 in the sucralfate and ranitidine groups, respectively. From days 3-13, Al serum levels were significantly higher with sucralfate than with ranitidine (P<0.05). On days 7-13, 24-h urinary Al excretion was also significantly higher in the sucralfate than in the ranitidine group (P<0.05).

CONCLUSION

In ICU patients, only approximately 50% of parenterally administered Al is eliminated renally. Sucralfate additionally increases patients exposure to Al. In ICU patients, the mean absorption of enteral Al from sucralfate is only 0.019%.

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.