Hyperkalemia
Serum potassium greater than 5.0 mEq/L
Definition
Hyperkalemia is a serum potassium level greater than 5.0 mEq/L. It is potentially life-threatening due to cardiac effects, making it the most dangerous electrolyte imbalance.
Causes
- Renal failure (most common)
- Potassium-sparing diuretics (spironolactone)
- ACE inhibitors, ARBs
- Massive tissue breakdown (crush injury, rhabdomyolysis, tumor lysis)
- Acidosis (H+ in, K+ out)
- Addison's disease
- Blood transfusion (old units)
Signs and Symptoms
Muscle weakness, paresthesia, nausea, diarrhea, ECG changes (peaked T waves, widened QRS, prolonged PR, absent P waves; ultimately sine wave and asystole).
Nursing Interventions (M-I-C-E-D mnemonic)
- M: Monitor ECG continuously
- C: Calcium gluconate (stabilizes myocardium; rapid action, no effect on K)
- I: Insulin + D50 (shifts K into cells)
- Beta-agonists (albuterol) (shifts K into cells)
- Sodium bicarbonate in acidosis
- Remove: Kayexalate (PO/PR), loop diuretics, dialysis
NCLEX Relevance
Peaked T waves = hyperkalemia cue. Calcium gluconate protects the heart.