Abstract: Objective To investigate the efficacy and safety of regional citrate anticoagulation(RCA) in continuous venous hemofiltration(CVVH) in critically ill patients. 
Methods A retrospective analysis of the general data of 668 critically ill patients who received CVVH treatment was performed.They were divided into the RCA group and unfractionated heparin(UFH) group based on anticoagulation methods. The acute physiology and chronic health(APACHEⅡ) score, causes of treatment with continuous renal replacement therapy(CRRT), filter life, reasons for suspension of hemofiltration, and complications between two groups were compared in both groups. 
Results The filter life of RCA group was longer than that of UFH group(P＜0.001). The proportion of filter life＜24 h in UFH group was higher than that in RCA group, and the proportion of filter life ≥48 h in UFH group was lower than that in RCA group, with significant difference(P＜0.05). There was no significant difference between two groups when the filter life was 24-48 h(P＞0.05). The causes of suspension of hemofiltration in two groups were analyzed. The coagulation ratio of filter in RCA group was lower than that in UFH group, the proportion of getting off the machine at the end of treatment was higher than that in UFH group, and the proportion of replacing filter in RCA group was higher than that in UFH group after treatment for more than 72 h(P＜0.05). There were no serious bleeding events in both groups. After treatment, there was no significant difference in serum total Ca2+, arterial blood pH, free Ca2+, Na+, HCO3- between two groups(P＞0.05). 
Conclusion Compared with UFH anticoagulation, RCA in critically ill patients undergoing CVVH can significantly prolong the filter life, reduce the application of supplies, and have no obvious metabolic complications or bleeding risk. It is expected to be the first-line anticoagulation method for CVVH treatment in ICU patients.

Key words: renal replacement therapy, citrate anticoagulation, critically ill patients