Compared with that in the citrate group , both PT and APTT in heparin group was significantly higher [ PT : ( 15.5 2.0 ) s vs ( 12.3 2.7 ) s , P < 0.001 ; APTT : ( 56.0 10.9 ) s vs ( 32.8 6.1 ) s , P < 0.001 ; respectively ] at 2 h during SLED.However , the PT and APTT levels in heparin group decreased afterwards and were similar with those in the citrate groups at 5 h during treatment .