Current leakage in hemodialysis machines may be a safety risk for patients

During hemodialysis, the dialysis fluid is conductive and allows current to flow from or to the machine if a difference in electrical potential occurs. This may cause a health risk for the patient. We investigated the presence of such current during various conditions in 17 dialysis machines: the Gambro AK10 (n = 5) and AK100 (n = 3), and the Fresenius 2008C (n = 3), 2008E (n = 2), and 4008E (n = 4). Current leakage measurements were performed without connection of the patient to the system by using a copper tube inserted into the stream of the dialysis fluid at the point where the patient would normally be connected to the dialyzer. The current leakage (measured in microA) at the ground site was significantly higher for the AK10 and the 2008C than for the AK100, 2008E, and 4008E machines. The current leakage, at the site where the dialyzer is located, was highest for the AK10 and less for the AK100, 2008C, 2008E, and 4008E. The 2008C and 2008E dialyzers had the highest maximal current leakage when a malfunctioning external device was attached while the AK100 had less and the AK10 had the least leakage. There was a great variation in leakage current among the dialysis machines. The greatest risk occurred when the patient also was connected to other electric devices with current leakage.