title: Online conductivity monitoring: validation and usefulness in a clinical trial of reduced dialysate conductivity.
abstract: Relatively low dialysate conductivity (Cndi) may improve outcomes by reducing the overall sodium burden in dialysis patients. Excess sodium removal, however, could lead to hemodynamic instability. We performed a randomized controlled trial of reduction of Cndi. For the study, 28 patients were randomized to maintenance of Cndi at 13.6 mS/cm (equivalent to 135 mmol/L of Na+) or serial reduction of Cndi in steps of 0.2 mS/cm, guided by symptoms and blood pressure. Sodium removal estimated from pre- and postplasma concentrations correlated well with removal measured by conductivity monitoring as ionic mass balance (R2 0.66, p < 0.0001). Of the 16 patients randomized to reduction of Cndi, 6 achieved Cndi 13.4 mS/cm, 6 achieved 13.2 mS/cm, and 4 achieved 13.0 mS/cm. No episodes of disequilibrium occurred. Interdialytic weight gain was reduced from 2.34 +/- 0.10 kg to 1.57 +/- 0.11 kg (p < 0.0001). Predialysis systolic blood pressure fell from 144 +/- 3 mm Hg to 137 +/- 4 mm Hg (p < 0.05). The reduction in convective sodium removal was balanced by an increase in diffusive sodium removal (95 +/- 9 mmol cf. 175 +/- 14 mmol, p < 0.0001). Reduction in Cndi monitored by IMB is safe and practical and leads to improved interdialytic weight gains and blood pressure control, while avoiding excessive sodium removal.
authors.affiliation: Department of Renal Medicine, Derby City General Hospital, Uttoxeter Road, Derby DE22 3NE.
authors.forename: Stewart H
authors.initials: SH
authors.lastname: Lambie
authors.forename: Maarten W
authors.initials: MW
authors.lastname: Taal
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Fluck
authors.forename: Christopher W
authors.initials: CW
authors.lastname: McIntyre
mesh_terms: D001794:Blood Pressure; D015314:Dialysis Solutions / Q000737:chemistry*; D004553:Electric Conductivity; D004566:Electrodes; D006801:Humans; D008875:Middle Aged; D008991:Monitoring, Physiologic; D006435:Renal Dialysis; D015203:Reproducibility of Results; D012964:Sodium / Q000097:blood*; D015430:Weight Gain
chemical_list: D015314:Dialysis Solutions; D012964:Sodium