Nickel contamination from an intravenous catheter used for infusion

At the outset of a clinical research project involving metal analyses on patients receiving metal devices in conjunction with hip fractures, unexpected high concentrations of nickel were discovered in serum samples taken before surgery. The median nickel concentration in 30 patients was 4.6 microg/l (highest 19.5 microg/l), while reference values in non-exposed persons are reported to be 0.05-1.2 microg/l. The sampling and analyzing procedures were scrutinized without positive identification of the source of contamination. A review of all relevant procedures was then undertaken. It was identified that the nickel contamination originated from the intravenous catheter which was always put in place immediately after the patient's admission to the hospital, and thus before the blood sampling. Close inspection of the intravenous catheter revealed that it contained a nickel-plated brass funnel inside the hub of the device which released nickel into the Ringer-acetate passing through the catheter. The present catheter has been the standard device used at Haukeland University Hospital for the past 6 years. Patients have consequently been exposed to small amounts of nickel. The clinical relevance of the exposure cannot be determined. For the patients included in the research project, a metal-free alternative was used. These findings show that the quality and properties of everyday medical devices should be scrutinized, at least before being used for special purposes.