Nephrol Dial Transplant (2002) 17: 1037-1044
© 2002 European Renal Association-European Dialysis and Transplant Association
Estimating phosphate removal in haemodialysis: an additional tool to quantify dialysis dose
1 Division of Nephrology, Kantonsspital Liestal, University of Basle, Switzerland, 2 Central Laboratory and Division of Nephrology, Kantonsspital Aarau, Switzerland, 3 Institute of Physiology, University of Graz, Austria, 4 Institute for Social and Preventive Medicine, University of Basle, Switzerland, 5 Institute for Social- and Preventive Medicine, University of Zürich, Switzerland and 6 Clinica Las Condes, Santiago, Chile
Background. Half of the dialysis population suffers from hyperphosphataemia, which is now recognized as a major factor of haemodialysis (HD) morbidity and mortality. Current control is focussed on reducing dietary phosphate intake and diminishing absorption using phosphate binders, whereas control and quantification of phosphate removal by HD is undervalued. The aim of this prospective study was to develop a simple, bedside formula to estimate dialytic phosphate removal in stable HD patients.
Methods. This was a prospective, randomized trial. Phosphate and urea elimination were assessed in a representative group of patients at two dialysis centres using randomly different dialysers (1.3–2.4 m2). Quantification was performed by partial dialysate collection, concentration measurements in blood and effluent dialysate spot samples, and Kt/Vurea during standard high-flux HD. Multiple linear regression analyses were used in 77% of all data sets to generate an equation to predict phosphate removal. The formula was validated in the remaining 23% of data sets, in the same group of patients using a large capillary filter, and in diabetic patients treated with a small dialyser at different blood flows (200, 250, and 300 ml/min).
Results. A formula allowing quantification of phosphate removal within one HD session was developed in 18 of 74 patients during 41 treatments (137 out of 177 data sets) and was determined as: MPO4pred=0.1t -17+50cds60+11cb60, where t is treatment time in min, cds60 and cb60 are phosphate concentrations in dialysate and plasma measured 60 min into HD in mmol/l, and MPO4pred is estimated phosphate removed in mmol. The precision was remarkable (r2=0.92–0.94). The comparison of phosphate and Kt/Vurea showed a significant association (r2=0.28), albeit with remarkable scatter.
Conclusions. We present the first approach to quantify phosphate removal during high-flux HD by a bedside formula. Only 28% of the variation in phosphate removal was explained by Kt/Vurea. It appears that other factors not adequately accounted for by Kt/Vurea affect phosphate removal. Therefore, we propose an individual control and quantification of phosphate removal in HD.
Keywords: dialysis dose; haemodialysis; hyperphosphataemia; phosphate kinetics
Correspondence and offprint requests to: Jean-Pierre Gutzwiller, MD, Division of Gastroenterology, University Hospital of Basle, CH-4031 Basle, Switzerland. Email: jeanlucjpg{at}hotmail.com
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  S. Eloot, W. van Biesen, A. Dhondt, R. de Smet, B. Marescau, P. P. De Deyn, P. Verdonck, and R. Vanholder Impact of increasing haemodialysis frequency versus haemodialysis duration on removal of urea and guanidino compounds: a kinetic analysis Nephrol. Dial. Transplant., July 1, 2009; 24(7): 2225 - 2232. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Jean, C. Chazot, and B. Charra Hyperphosphataemia and related mortality Nephrol. Dial. Transplant., February 1, 2006; 21(2): 273 - 280. [Full Text] [PDF]
|
|