Hyperkalemia: ECG Changes, Causes & Priority Nursing Actions

By an RN · High-yield lab value + cardiac topic

Causes to know

• Renal failure — the #1 cause (kidneys can't excrete K+)
• Medications: ACE inhibitors, ARBs, potassium-sparing diuretics (spironolactone — "saves K+"), trimethoprim
• Acidosis — H+ moves into cells, K+ moves out
• Addison's disease (low aldosterone = retains K+)
• Cell destruction: hemolysis, crush injuries, tumor lysis, massive blood transfusion
• Salt substitutes (potassium chloride) and K+ supplements

ECG progression (memorize this order)

Treatment order (the NCLEX tests the sequence)

1. Calcium gluconate or calcium chloride IV — FIRST when there are ECG changes. It stabilizes the cardiac membrane. It does not lower potassium — it buys time.
2. Shift K+ into the cells: regular insulin IV + glucose (prevents hypoglycemia), and/or nebulized albuterol. Temporary fix.
3. Remove K+ from the body: sodium polystyrene sulfonate (Kayexalate), loop diuretics if kidneys work, and dialysis — the definitive removal, especially in renal failure.
4. Stop the source: hold K+ supplements, K+-raising meds, salt substitutes.

What the NCLEX actually asks

• Patient with peaked T waves + K+ 6.8 → give calcium first, then insulin/glucose. Order matters.
• Spironolactone patient with muscle weakness → think hyperkalemia.
• Kayexalate + sorbitol → watch for bowel necrosis; never give post-op or to a patient with reduced gut motility without an order review.
• Continuous cardiac monitoring is a given — never leave the hyperkalemic patient unmonitored.

Memory trick

"K+ goes up, T goes up (peaked T)." And treatment is Calm the heart, Shift it, Dump it — calcium, shift, eliminate.