Potassium kinetics during hemodialysis

Abstract

Hyperkalemia in hemodialysis patients is associated with high mortality, but prescription of low dialysate potassium concentrations to decrease serum potassium levels is associated with a high incidence of sudden cardiac arrest or sudden death. Improved clinical outcomes for these patients may be possible if rapid and substantial intradialysis decreases in serum potassium concentration can be avoided while maintaining adequate potassium removal. Data from kinetic modeling sessions during the HEMO Study of the dependence of serum potassium concentration on time during hemodialysis treatments and 30 minutes postdialysis were evaluated using a pseudo one-compartment model. Kinetic estimates of potassium mobilization clearance (K(M)) and predialysis central distribution volume (V(pre)) were determined in 551 hemodialysis patients. The studied patients were 58.8 ± 14.4 years of age with predialysis body weight of 72.1 ± 15.1 kg; 306 (55.4%) of the patients were female and 337 (61.2%) were black. K(M) and V(pre) for all patients were non-normally distributed with values of 158 (111, 235) (median [interquartile range]) mL/min and 15.6 (11.4, 22.8) L, respectively. K(M) was independent of dialysate potassium concentration (P > 0.2), but V(pre) was lower at higher dialysate potassium concentration (R = -0.188, P < 0.001). For patients with dialysate potassium concentration between 1.6 and 2.5 mEq/L (N = 437), multiple linear regression of K(M) and V(pre) demonstrated positive association with predialysis body weight and negative association with predialysis serum potassium concentration. Potassium kinetics during hemodialysis can be described using a pseudo one-compartment model.

Dialysate Potassium, Serum Potassium, Mortality, and Arrhythmia Events in Hemodialysis: Results From the Dialysis Outcomes and Practice Patterns Study (DOPPS)

“…7,8 Potassium has the potential to move freely across the dialyzer membrane during the HD session, typically being transferred from a patient’s blood into the dialysate. 9 The dialysate potassium (DK) concentration is a modifiable factor that can alter SK concentrations throughout the HD session and thus potentially impacts the risk for arrhythmias and cardiac arrest. 10 Results of studies examining DK effects on sudden death and all-cause mortality have been mixed.…”

Prescriptions of dialysate potassium concentration during short daily or long nocturnal (high dose) hemodialysis

“…Potassium kinetic parameters based on a pseudo one‐compartment model were previously determined from thrice weekly hemodialysis kinetic modeling sessions during the HEMO Study and were used in this study to represent a typical hemodialysis patient population. The HEMO Study was approved by the institutional review board at each of the 15 clinical centers, and all patients gave written informed consent .…”

“…Potassium kinetic parameters based on a pseudo one‐compartment model were previously determined from thrice weekly hemodialysis kinetic modeling sessions during the HEMO Study and were used in this study to represent a typical hemodialysis patient population. The HEMO Study was approved by the institutional review board at each of the 15 clinical centers, and all patients gave written informed consent . Kinetic modeling sessions were performed by collection of blood samples predialysis, 60 minutes after starting the treatment, 20 seconds after stopping the treatment using a slow flow technique, and 30 minutes after the end of the treatment.…”

“…We have recently used a pseudo one‐compartment mathematical model to describe potassium kinetics during thrice weekly hemodialysis based on data from a large number of patients in the HEMO Study . That study demonstrated significant interpatient variability in potassium kinetics that could be characterized by individualized potassium kinetic parameters.…”

A Bayesian approach for the identification of patient-specific parameters in a dialysis kinetic model

“…calcium, potassium and phosphorus, that play a crucial role for hydro-electrolyte equilibria. [16][17][18] To achieve more effective prediction models, multi-pool models have been introduced, allowing to describe the simultaneous contribution of different plasma solutes. 19 However, none of these models aim at characterizing the patientspecific solute kinetics in HD, apart from Ursino et al, 19 in which an individual estimation of few parameters characterizing solute kinetics has been performed.…”