Cardiac output remained more stable in extended sessions ( change during HD@ , -@ L/min ; during HDF@ , -@ L/min ; during HD@ , -@ L/min -LSB- P = @ vs. HDF@ -RSB- ; and during HDF@ , -@ L/min -LSB- P = @ vs. HD@ ; P = @ vs. HDF@ ) , in line with the decreased relative blood volume slope in long dialysis .