Abstract: 【Abstract】Objective To judge and analyze the causes of heparin dosage deviation in hemodialysis from the aspects of dialysis equipment and syringe. Method The speed of heparin pump in dialyzer was set as 1 ml/h, 2ml/h, 5 ml/h, and 10ml/h, respectively. ①The injection flow of heparin pump in dialyzer with different operatingtime was measured without changing the type of syringes. ② The injection flow of heparin pump was measured in the same dialysis machine after applying 6 brands of 20ml disposable medical syringes. Results ①The flow errors of heparin pump in dialyzer with different operating time were all less than ±5%. The measured flow of heparin pump in the dialyzer of group B (running time of 20000h to 35000h,n=6) was lower than the set value at different speed measurement points, which was significantly different from that of group A (running time of 10,000h to 20,000 h, n=6)(1ml/h：t=2.857，P=0.021；2ml/h：t=2.32,P=0.042; 5ml/h: t=3.295, P= 0.007). ②There were significant differences in the detection results of the 6 brands of syringes at the measuring points with different set speeds. (1ml/h:H=16.685，P=0.005；2ml/h：H=18.675， P=0.002，P=0.042;5ml/h: H=21.654，P=0.001；10ml/h：H=19.773，P=0.001). Conclusion In order to ensure accurate and stable operation of heparin pump, daily maintenance and maintenance are very important. When replacing the brand of the syringe, important parameters such as the inner diameter of the syringe should be understood in detail,and the setting parameters in the dialysis machine should be changed in time if they are different from those before.

Key words: Heparin pump, Syringe, Dialyzer upkeep