title: What is good about PD + HD combined therapy.
abstract: It is known that β(2) -microglobulin (β(2) -MG) concentration in peritoneal dialysis (PD) patients is inversely correlated to the residual renal function (RRF). With decreasing RRF, some PD patients may necessarily be treated with hemodialysis (HD) once a week, not only for removing excess water and small solutes, but also for removing much larger solutes such as β(2) -MG. In this study, a kinetic model allowed us to show what is good about PD + HD combined therapy in long-term PD patients. A mathematical model was established based on a classic compartment theory for clinical use. Model validations were made by comparing calculated results with clinical data in order to specify what was good about PD + HD combined therapy (5-day PD + 1-HD/week). Time-averaged concentration (TAC) for urea and creatinine decreased by 20% on the average by introducing PD+HD combined therapy no matter which dialyzers were used. TAC for β(2) -MG in PD+HD combined therapy, however, was strongly dependent upon the dialyzer clearance, and when a low flux dialyzer (clearance for β(2) -MG = 10 mL/min under Q(B)  = 200, Q(D)  = 500 mL/min) was used, pre-dialysis β(2) -MG concentration may increase. Use of super high-flux dialyzers (clearance for β(2) -MG = 60 mL/min under the same conditions) should greatly reduce the β(2) -MG concentration from 30 to 8 mg/L in 4-hr treatment. Then, when PD+HD combined therapy is introduced to a PD patient with diminishing RRF, use of super high-flux dialyzers may be strongly recommended in order not to increase concentrations of pre-dialysis β(2) -MG and/or even greater solutes. Use of super high-flux dialyzers is a key to the success of PD+HD combined therapy that could prevent concentrations of large solutes from increasing.
authors.affiliation: Department of Human and Environmental Science, College of Engineering, Shonan Institute of Technology, Fujisawa, Kanagawa, Japan. yama@la.shonan-it.ac.jp
authors.forename: Akihiro C
authors.initials: AC
authors.lastname: Yamashita
authors.forename: Narumi
authors.initials: N
authors.lastname: Tomisawa
mesh_terms: D003131:Combined Modality Therapy; D006801:Humans; D007676:Kidney Failure, Chronic / Q000378:metabolism / Q000628:therapy*; D007700:Kinetics; D008954:Models, Biological; D010530:Peritoneal Dialysis / Q000379:methods*; D006435:Renal Dialysis / Q000379:methods*; D001613:beta 2-Microglobulin / Q000378:metabolism
chemical_list: D001613:beta 2-Microglobulin