Abstract: Objective To find out suitable maintenance methods for ultrafiltration function of hemodialysis machines. Method We selected the hemodialysis machines in our hospital, and divided them by ultrafiltration pump type into 2 groups: group A (17 machines with fixed capacity membrane pumps), and group B (11 machines with ceramic piston pumps). We measured ultrafiltration errors of the machines in the 2 groups at different situations. We also reviewed and analyzed the ultrafiltration malfunction rate and its causes in the period from Jan. 2004 to Jun. 2012. Result ①There were significant differences in ultrafiltration errors between the 2 groups after calibration for 9 months (t =2.261, P=0.042) and for 12 months (t =2.364, P=0.026). ②There was no significant difference in ultrafiltration malfunction rate between the 2 groups (χ2=0.635, P= 0.425). ③There were significant differences in causes of ultrafiltration malfunction between the 2 groups (χ2= 10.763, P=0.013). Conclusion The causes for ultrafiltration malfunction were significantly different between the 2 groups of hemodialysis machines. We could analyze these causes from the maintenance record, and use appropriate methods to maintain the ultrafiltration function.

Key words: Hemodialysis machine, ultrafiltration, maintenance