Hemodialysate composition and intradialytic metabolic, acid–base and potassium changes

Abstract

We compared the effects of dialysate composition on changes in intermediary metabolites, acid-base balance, and potassium removal during hemodialysis. Patients were dialyzed against dialysates containing acetate or bicarbonate, each with or without glucose, in a four-way cross-over study. Dialysates containing acetate were associated with significant perturbations in intermediary metabolism, including increases in blood citrate, acetoacetate and beta-hydroxybutyrate and a decrease in pyruvate. In contrast, bicarbonate-containing dialysates caused minimal perturbations in intermediary metabolism. Addition of glucose to the dialysate decreased the changes in intermediary metabolites; however, the magnitude of this effect was less than that observed for the change from acetate to bicarbonate. Use of acetate also resulted in lower post-dialysis blood-concentrations of base equivalents than obtained with bicarbonate; this difference was unaffected by the presence or absence of glucose. Although pre- and post-dialysis potassium concentrations were unaffected by the dialysate formulation, total potassium removal was significantly greater when glucose was omitted from the dialysate. Our results suggest that both bicarbonate and glucose should be included in the dialysate, particularly for those patients whose capacity for metabolism may be limited because of highly efficient dialysis, intercurrent illness, or starvation. However, addition of glucose to the dialysate may require a reduction in dialysate potassium to maintain proper potassium homeostasis.

Intradialytic Hypercapnic Respiratory Failure Managed by Noninvasive Assisted Ventilation

“…The extent of bicarbonate titration is related to the degree of predialysis metabolic acidosis and the intradialytic production of organic acids [3,4], which is augmented in the presence of tissue hypoxia or malnutrition [5,6]. Increased buffering results in increased production of CO 2 , but usually is not associated with significant hypercapnia or hypoxemia [7,8].…”

Medical and dialytic management of hyperkalemia in hemodialysis patients

“…The former accounts for only 15% of total potassium removal and depends primarily on the volume of ultrafiltration (10). Dialytic removal (-50 mmol during an average session) accounts for the remaining 85% and is largely determined by the blooddialysate potassium gradient (10)(11)(12)(13). Plasma potassium decreases rapidly in the first hour of hemodialysis, at a slower rate in the second hour, and remains fairly constant during the remainder of the dialysis session (10,11).…”

“…Both insulin and beta-2 adrenergic agonists stimulate potassium shifts from the extracellular to the intracellular fluid compartment, thereby attenuating the blood-dialysate potassium concentration gradient. Thus dialytic potassium removal is lower when a 200 mg/dl glucose dialysate is used, as compared with dialysis against a glucose-free dialysate (12,13). The former maneuver increases plasma insulin concentrations during dialysis (10), thereby promoting intracellular potassium shifts and decreasing the blooddialysate potassium gradient.…”

The Effect of Glucose Added to the Dialysis Fluid on Blood Pressure, Vasoactive Hormones and Energy Transfer during Hemodialysis in Chronic Renal Failure

“…Among the advantages were prevention of both glucose loss and a decrease in respiratory quotient, decreased risk of both hypoglycemia and incidence of headache and post-dialysis fatigue, and donation of energy to patients [3][4][5][6][7][8][9]. Among the disadvantages were increased costs, decreased potassium elimination, and augmentation of risk for bacterial growth in liquid bicarbonate concentrates.…”

“…This can be due to manifest or undiagnosed hypoglycaemia [1,2], since 15 g -30 g of glucose is removed during a dialysis session [3][4][5][6]. Hypoglycaemia can be prevented or the incidence can be decreased by addition of glucose to the dialysis fluid [4][5][6], and the occurrence of headache and fatigue is reduced [5,7,8].…”