title: Substituting citrate for lactate in peritoneal dialysis fluid improves ultrafiltration in rats.
abstract: BACKGROUND
  Exposure to peritoneal dialysis (PD) fluid induces an inflammatory response in the peritoneal cavity. Blockers of complement and coagulation have improved ultrafiltration in animal models of PD. Citrate is a clinically established anticoagulant that also blocks complement activation.
  
  
  OBJECTIVE
  The aim of the present study was to evaluate the effects on ultrafiltration of a gradual substitution of citrate for lactate in an experimental model of PD.
  
  
  METHODS
  Fractions (0, 5, 10, and 15 mmol/L) of the 40 mmol/L lactate buffer of filter-sterilized 2.5% glucose PD fluid were replaced by citrate. The modified fluids were compared in a rat model of single PD fluid exposure through an indwelling catheter. The initial kinetics of citrate and ionized calcium were evaluated in separate, single, short time dwell experiments.
  
  
  RESULTS
  Replacing 10 and 15 mmol/L of the lactate buffer by sodium citrate significantly increased osmotic ultrafiltration (by 24.7%+/-7.7% at 10 mmol/L), net ultrafiltration, and glucose retention at 4 hours of dwell time in the rat model. Osmotic ultrafiltration was significantly correlated to citrate concentration and glucose concentration. Citrate was rapidly eliminated from the peritoneal cavity, concentrations falling to less than half in 1 hour and concentrations of calcium ions concomitantly normalized.
  
  
  CONCLUSIONS
  Substituting citrate for lactate induced a dose-dependent increase in ultrafiltration. Mechanisms probably involve the relation between diffusion and ultrafiltration, leading to increased glucose retention. The increase in ultrafiltration was quantitatively important at a citrate concentration (10 mmol/L) that is compatible with clinical applications of citrate.
authors.affiliation: Department of Biomedicine, Göteborg University, Göteborg, Sweden.
authors.forename: Nicola
authors.initials: N
authors.lastname: Cavallini
authors.forename: Anders
authors.initials: A
authors.lastname: Wieslander
authors.forename: Magnus
authors.initials: M
authors.lastname: Braide
mesh_terms: D000818:Animals; D001202:Ascitic Fluid / Q000737:chemistry; D002951:Citrates / Q000008:administration & dosage*; D015314:Dialysis Solutions / Q000494:pharmacology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D007274:Injections, Intraperitoneal; D007773:Lactates / Q000032:analysis / Q000302:isolation & purification*; D008297:Male; D010530:Peritoneal Dialysis / Q000379:methods*; D010537:Peritoneum / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D014462:Ultrafiltration / Q000379:methods*
chemical_list: D002951:Citrates; D015314:Dialysis Solutions; D007773:Lactates