Sodium polystyrene sulfonate used to reduce the potassium content of a high-protein enteral formula: a quantitative analysis.
BACKGROUND
Sodium polystyrene sulfonate (Kayexalate) commonly is used in treating hyperkalemia. As a cation exchange resin, it also can be used to reduce the potassium content of enteral nutrition formulas. This study evaluates the use of Kayexalate to reduce potassium in one high-protein enteral formula and describes the quantitative analysis of the product.


METHODS
Sodium polystyrene sulfonate and enteral formula were mixed into a slurry and allowed to settle, and then the supernatant was decanted off and tested as samples. Three sample concentrations were analyzed: a control not subjected to potassium reduction, 0.5 g of Kayexalate per mEq K+ sample, and a 1 g/mEq K+ sample. Of these samples, moisture, lipid, protein, carbohydrate, ash, and mineral content were obtained.


RESULTS
Compared with the control, the percentage decrease of potassium ranged from 25% to 36%, depending on the concentration of Kayexalate. A significant increase of 324% in sodium concentration was found in the 1.0 g/mEq K+ sample. Although there was no change in magnesium content, a slight increase in phosphorus, iron, and zinc was evident.


CONCLUSIONS
The treatment of an enteral formula with sodium polystyrene sulfonate significantly increases its sodium content, with a modest decrease in potassium content. Clinicians using this method in clinical practice should be aware of the increase in sodium content.
Rivard
Andrew L
AL
Department of Surgery, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA.
Raup
Sandra M
SM
Beilman
Gregory J
GJ
D002411:Cation Exchange Resins / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004750:Enteral Nutrition; D005526:Food, Formulated / Q000032:analysis*; D006801:Humans; D011137:Polystyrenes / Q000494:pharmacology*; D011188:Potassium / Q000032:analysis* / Q000737:chemistry; D012964:Sodium / Q000032:analysis*
D002411:Cation Exchange Resins; D011137:Polystyrenes; C003321:polystyrene sulfonic acid; D012964:Sodium; D011188:Potassium