@nursesabina: NCLEX-RN Review: The Insulin-Potassium Shift Question 1 (Knowledge/Comprehension) A nurse is reviewing the lab results for a patient diagnosed with Diabetic Ketoacidosis (DKA) who has just received an intravenous insulin infusion. The nurse should be most alert for a critical decrease in which of the following electrolytes? A. Sodium (Na + ) B. Calcium (Ca 2+ ) C. Potassium (K + ) D. Chloride (Cl − ) Correct Answer: C. Potassium (K + ) Detailed Rationale: The primary mechanism of action of insulin relevant here is its ability to facilitate the movement of glucose into cells. However, it concurrently activates the sodium-potassium ATPase pump in the cell membrane. This pump actively moves potassium (K + ) ions from the extracellular space (the blood) into the cells. In DKA, this effect is dramatic. Even though total body potassium may be low due to other factors (like osmotic diuresis), the initial effect of insulin is to drive the remaining potassium into the cells, potentially causing life-threatening hypokalemia (low serum potassium). Therefore, monitoring serum potassium is a critical nursing priority, as highlighted by the "Nursing Imperative" in the diagram. Sodium (A) is also affected but usually rises (or its effect is secondary to hypernatremia), and calcium and chloride (B, D) are less directly or critically impacted in this specific context. Question 2 (Analysis/Application) The healthcare provider orders a combined infusion of regular insulin and dextrose (e.g., D5W or D10W) for a patient with acute, symptomatic hyperkalemia (serum potassium > 6.0 mEq/L). The patient's blood glucose level is currently within the normal range. When the patient asks why they are receiving sugar (dextrose) since they are not diabetic, which is the nurse's best response? A. "The sugar will help to carry the potassium out of your body more quickly." B. "The dextrose is given to prevent your blood sugar from dropping too low from the high dose of insulin needed." C. "Insulin works faster when you have more sugar available for it to move into your cells." D. "This medication combination is the fastest way to replace the normal fluids you have lost." Correct Answer: B. "The dextrose is given to prevent your blood sugar from dropping too low from the high dose of insulin needed." Detailed Rationale: This scenario illustrates the third panel of the design, "MANAGEMENT OF HYPERKALEMIA." The primary therapeutic goal is to shift potassium into the cells and away from the heart (to prevent cardiac arrhythmias). Insulin is used to achieve this rapid "inward shift." However, because insulin also moves glucose into the cells, it will significantly lower the patient's blood glucose level, which can cause severe, life-threatening hypoglycemia (very low blood sugar). Dextrose is simultaneously administered specifically as a protective measure to maintain a normal blood glucose level while the insulin performs its job of shifting potassium. Option A is incorrect; the insulin-dextrose combination does not remove potassium from the body (elimination occurs via the kidneys or other means, like dialysis). Option C is incorrect; insulin effectiveness isn't increased by high glucose; rather, its action causes low glucose. Option D is incorrect; while fluids are used in many critical care situations, this specific combination is for its electrolyte-shifting effect, not primarily for fluid replacement.

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Wednesday 11 March 2026 16:50:44 GMT