METHODS
Critically ill TTP patients receiving a dose of 3 g CFP/SUL (2.0 g/1.0 g) intravenously every 8 h were included in the study. Serial blood samples were collected at 0, 1, 2, 3, 4, 6, and 8 h at the third infusion with TPE (Session I) and the sixth infusion without TPE (Session II). Effluent samples were also collected at the effluent port of plasma eliminated during TPE. Concentrations of CFP and SUL in plasma and effluent were measured using LC/MS/MS.