单项选择题

A.尿素下降率(Urea Reduction Rare ,URR)
B.时间平均尿素浓度(Time Average Concentration For Urea ,TACure)
C.溶质清除指数(Solute Removal Index,SRI)
D.蛋白质分解代谢率(Protein Catabolic Rate,PCR)
E.尿素生成率(Urea Nitrogen Appearance,UNA )