title: High- and low-flux acetate-free biofiltration: experimental assessment of calcium mass balance and intact parathyroid hormone behaviour.
abstract: We studied total calcium mass balance and plasma intact parathyroid hormone behaviour in 10 uraemic patients who underwent acetate-free biofiltration carried out in accordance with six different dialytic schedules, where either a polyacrylonitrile or a polysulphone membrane was used. Schedules 1 and 2 involved a reinfusion flow rate of 33.3 ml/min with a dialysate calcium concentration (DCa) of 1.75 and 2 mmol/l respectively; in schedule 3, 4, 5 and 6 reinfusion flow rate amounted to 50 ml/min and DCa was respectively of 1.75, 2, 2.25 and 2.5 mmol/l. Dehydration remained unchanged in all schedules: 700 g/h. Finally high- and low-flux acetate-free biofiltration are able to induce different Ca mass balance which may suit different therapeutic contexts. Ca mass balance was either positive or negative depending on reinfusion flow rate and DCa. With a reinfusion flow rate of 33.3 ml/min a DCa of at least 2 mmol/l was necessary to obtain a positive mass balance, while with a reinfusion flow rate of 50 ml/min DCa had to equal 2.25 mmol/l. In high-flux acetate-free biofiltration, the estimation of predialytic Ca2+ and DCa values, using a simple formula, allows prediction of the mass balance that will be attained. At the end of acetate-free biofiltration, intact parathyroid hormone always decreased when a polyacrylonitrile membrane was employed while it increased, in the presence of negative Ca mass balance with a polysulphone membrane.
authors: Servizio Nefrologia e Dialisi, Ospedale Civile di Vigevano, Pavia, Italy.
authors: A
authors: A
authors: de Vincenzi
authors: R G
authors: RG
authors: Bellazzi
authors: M
authors: M
authors: Santagostino
authors: A
authors: A
authors: Gazo
authors: D
authors: D
authors: Romanini
authors: M
authors: M
authors: Nai
authors: L
authors: L
authors: Maretti
authors: G
authors: G
authors: Ornati
authors: R
authors: R
authors: Bellazzi
mesh_terms: D000085:Acetates; D002118:Calcium / Q000097:blood*; D015314:Dialysis Solutions; D005260:Female; D006801:Humans; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D006435:Renal Dialysis; D014511:Uremia / Q000097:blood* / Q000628:therapy
chemical_list: D000085:Acetates; D015314:Dialysis Solutions; D008567:Membranes, Artificial; D010281:Parathyroid Hormone; D002118:Calcium