【Abstract】Objective To discuss clinical application value of the modified pre-flushing method by soaking slowly and rushing fast in heparin-free hemodialysis. Methods A total of 38 patients of heparin-free dialysis in the Blood Purification Center of Tongxiang First People’s Hospital from Jan. 2018 to Mar. 2019 were enrolled in this study. They were randomly divided into two groups. The traditional pre-flushing method of dialyzer and pipeline was used in the group A (n=19), and the modified method of soaking slowly and rushing fast was used in the group B (n=19). The observation period was 4 dialysis sessions for every patient. Blood clotting grade in dialyzer and pipeline, the number of flushing by normal saline, and actual dialysis time were

recorded. eKt/V was estimated at the fourth hemodialysis session for every patient. Results Blood clotting in dialyzer and pipeline at 0、II and III grades were better in group B than in group A (t=7.851, 3.437 and 8.774 respectively; P=0.013, 0.009 and ＜0.001 respectively). Normal saline flushing for 0, 1, 3 and ≥4 times were statistically different between group A and B (t=7.602, 8.959, 5.848 and 8.192 respectively; P=0.031, 0.006, 0.024 and 0.018 respectively). The percentage of hemodialysis time greater than or equal to 3h was 87.2% and 97.4% in group A and B respectively (t=6.752, P=0.011). The rate of eKt/V compliant with the standard was 82.1% in group A and 94.8% in group B (t=8.039, P=0.023). Conclusion The modified preflushing method of soaking slowly and rushing fast in heparin-free hemodialysis was simple, inexpensive and safe and did not affect the adequacy of hemodialysis. This method is worthy to be used clinically.