A 52-year-old man with chronic kidney disease (eGFR 18 mL/min/1.73m²) presents with serum potassium 6.8 mEq/L. Which of the following is NOT an appropriate acute management strategy for symptomatic hyperkalemia in this patient?

Explanation

## Acute Management of Symptomatic Hyperkalemia **Key Point:** Acute management of symptomatic hyperkalemia (K⁺ >6.5 mEq/L with ECG changes) requires interventions that either stabilize the cardiac membrane or shift potassium intracellularly. Definitive removal is slower and not the primary goal in the acute phase. ### Appropriate Acute Interventions | Intervention | Mechanism | Onset | Duration | Notes | |---|---|---|---|---| | **Calcium gluconate** | Stabilizes cardiac membrane | 1–3 min | 30–60 min | First-line for ECG changes; does NOT lower K⁺ | | **Insulin + dextrose** | Shifts K⁺ intracellularly via Na⁺-K⁺-ATPase | 10–20 min | 4–6 hours | Rapid, effective; risk of hypoglycemia | | **Sodium bicarbonate** | Alkalinizes plasma; shifts K⁺ intracellularly | 30–60 min | 2–4 hours | Useful in metabolic acidosis; slower than insulin | | **Beta-2 agonists** (albuterol) | Stimulates Na⁺-K⁺-ATPase | 30 min | 4–6 hours | Alternative to insulin; less hypoglycemia risk | ### Why Sodium Polystyrene Sulfonate Is NOT Acute Therapy **High-Yield:** Sodium polystyrene sulfonate (Kayexalate) is a **cation-exchange resin** that binds potassium in the **colon**. Its onset is **6–24 hours** (or longer), making it unsuitable for symptomatic or life-threatening hyperkalemia. It is a **chronic/preventive agent**, not an acute stabilizer. **Clinical Pearl:** In acute symptomatic hyperkalemia with ECG changes (peaked T waves, prolonged PR, widened QRS), the priority is: 1. Stabilize the myocardium (calcium) 2. Shift K⁺ intracellularly (insulin, beta-2 agonists, bicarbonate) 3. Remove K⁺ from the body (diuretics, dialysis, ion exchangers — these are slower) **Warning:** Do not confuse **acute management** (shift/stabilize) with **chronic management** (remove). Sodium polystyrene sulfonate is appropriate for chronic hyperkalemia or prevention in CKD, but not for acute symptomatic episodes. ### Summary of Options - **Calcium gluconate:** ✓ Correct — stabilizes membrane, first-line for ECG changes - **Insulin + dextrose:** ✓ Correct — shifts K⁺ intracellularly, rapid onset - **Sodium bicarbonate:** ✓ Correct — shifts K⁺ intracellularly, especially if acidotic - **Sodium polystyrene sulfonate:** ✗ **WRONG** — onset 6–24 hours; not acute therapy [cite:Harrison 21e Ch 280]