How can glucose help hyperkalemia?

Insulin + Glucose: The combination of the above actually helps move potassium from the blood into cells. It is a treatment for hyperkalemia within a hospital setting sometimes.

It's the insulin: Insulin shifts potassium from the bloodstream into cells. In order to give this safely to a patient with hyperkalemia, glucose is also given. Otherwise, the serum glucose level may drop too low in the process of the Insulin moving potassium intracellularly.