Abstract: Objective  To discuss the efficacy and safety of double plasma molecular adsorption system (DPMAS) in the different length of treatment time.   Methods   This is a prospective cohort study, including patients who received DPMAS treatment in West China Hospital of Sichuan University from September 2022 to December 2023.They were divided into 2h, 3h and 4h groups according to the actual treatment time, to analyze changes in the proportion of bilirubin clearance, coagulation function, albumin and platelet levels, and the incidence of coagulation events before and after treatment in different groups of patients.  Results  A total of 99 patients with liver failure were included, including 136 treatments. Proportion of bilirubin decline before and after treatment: The 2h group was (24.05 ± 8.95)%, the 3h group was (27.98±10.83)%, and the 4h group was (30.44 ± 8.81)%, with statistical differences (F=4.607, P=0.012). There was a statistically significant difference (t=-3.296, P=0.001) in the proportion of bilirubin decrease between the 2h and 4h groups and no statistically significant difference between the 2h and 3h groups (t=1.783, P=0.078), and the 3h and 4h groups (t=-1.244, P=0.216). There were no significant differences in the changes of activated partial thromboplastin time (APTT) (F=1.994, P=0.369), albumin (F=2.411, P=0.300), platelet (F=3.736, P=0.369) and incidence of coagulation events (χ２=0.856, P=0.746) among different treatment time groups. The decrease ratio of bilirubin in different periods: in the 4h group (25.35±5.92) % in 0～2h, (3.29±3.29) % in 2～3h, (1.8±3.99) % in 3～4h, in the 3h group (24.02±10.31) % in 0～2h, and (3.96±3.91) % in 2～3h.  Conclusion  This study validated the effectiveness and safety of DPMAS treatment. The bilirubin clearance ratio showed the highest trend in the first 2 hours and gradually decreased over time. Compared with the 2-hour treatment group, the proportion of bilirubin decrease before and after treatment was significantly increased in the 3-hour and 4-hour treatment groups. At the same time, there were no significant differences in APTT, albumin, and coagulation event incidence among the groups. Therefore, this study suggests that the single treatment time of DPMAS should be guaranteed to be at least 2h, and can be extended to 4h.

Key words: Double plasma molecular adsorption system, Treatment times, Efficacy, Safety