Release of some trace metals from disposable coils during hemodialysis

In a previous study, we demonstrated that certain disposable coils are contaminated with zinc and release substantial quantities of zinc during hemodialysis, producing high postdialysis plasma zinc concentrations. The present investigation was undertaken to monitor plasma and dialysis fluid zinc and copper throughout dialysis and to estimate plasma zinc and copper uptake. Aluminum, cadmium, and lead release from coils was also determined. Venous plasma, arterial plasma, and coil chamber fluid were sampled periodically during dialysis; the trace metal concentrations were determined by flame atomic absorption spectrophotometry. Release of considerable quantities of zinc from the coils into the dialysis fluid, with uptake into the patient's plasma, was found. Approximately one-half of the plasma zinc uptake occurred within the first 45 min. Coils from different lots released significantly (p less than 0.001) different quantities of zinc. Plasma uptake of zinc ranged from 3.2 mg to 23.0 mg, with a mean (+/-SD) of 15.0 +/- 6.1 mg. Copper release and uptake was low. No detectable release of lead, cadmium, or aluminum was observed. The results suggest that zinc release from disposable dialysis coils should be assessed before recommending that hemodialysis patients receive zinc supplements.