Why do you give potassium in hyperglycemia?

Answer 1

Potassium levels often drop initially via increased urine output from the hyperglycemia caused osmotic diuresis.

To make matters worse, the insulin, that will undoubtedly be used to treat the hyperglycemia, will also pull the free floating potassium into cells, and out of the blood stream where the body cannot utilize the potassium. This can result in cardiac arrhythmias and death. Therefore potassium must be administered with insulin to treat severe hyperglycemia, even when potassium levels don't seem critically low.

Answer 2

Potassium is given in hyperglycemia to prevent the risk of developing low potassium levels (hypokalemia) due to high glucose levels. Insulin therapy used to lower blood sugar can shift potassium into cells, potentially causing hypokalemia if not monitored and supplemented accordingly.