Asking the question again: are cation exchange resins effective for the treatment of hyperkalemia?

Abstract
Sodium polysterene sulfonate (Kayexalate®) is a cross-linked polymer to which reactive sulfonic groups are attached and preloaded with sodium (Na+). When placed in a solution, its reactive sulfonate groups exchange their bound Na+ for another cation in the solution. Sodium polysterene sulfonate (SPS) [Although ‘SPS’ is often used as an abbreviation for sodium polystyrene sulfonate, SPS® is actually a brand name for sodium polystyrene sulfonate in sorbitol.] has long been used for the treatment of hyperkalemia, assuming that its reactive sulfonate groups exchange bound Na+ for potassium (K+) in the lumen of the gastrointestinal (GI) tract, causing loss of K+ in stool.