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Hyperkalemia: Correction & Management
Classification by Severity
| Severity | Serum K⁺ | Action |
|---|
| Mild | 5.5 - 6.0 mEq/L | Observe; eliminate exogenous K⁺ sources |
| Moderate | 6.1 - 6.9 mEq/L | Active shifting ± removal |
| Severe | ≥ 7.0 mEq/L | Immediate intervention; cardiac monitoring |
ECG Changes (Sequential with Rising K⁺)
The ECG below shows severe hyperkalemia with QRS widening merging into T waves and absent P waves:
Progressive ECG changes:
- Peaked (tall, narrow, symmetric) T waves - K⁺ > 5.5-6.5 mEq/L
- Flattened P wave + prolonged PR interval - K⁺ > 6.5-7.5 mEq/L
- Wide QRS complex - K⁺ > 7.0-8.0 mEq/L
- Sine wave pattern (QRS merges with T) - impending VF/asystole
- Ventricular fibrillation / asystole
Note: ECG changes may be absent even with severe hyperkalemia - a normal ECG does not exclude the diagnosis. Hyperkalemia can also mimic Brugada pattern or cause atropine-resistant bradycardia.
Three-Step Treatment Approach
Step 1 - Cardiac Membrane Stabilization (Buys Time)
Calcium - acts within 1-3 minutes, lasts 30-60 minutes. Does NOT lower serum K⁺.
| Agent | Dose | Route | Notes |
|---|
| Calcium gluconate 10% | 10-30 mL IV over 2-3 min; repeat in 5 min if needed | Peripheral IV preferred | First choice; less tissue damage if extravasation |
| Calcium chloride 10% | 10 mL (1 g) IV | Central line preferred | Contains 3× more Ca²⁺ than gluconate; risk of tissue necrosis peripherally |
Mechanism: restores the depolarization threshold, narrows QRS, reduces myocyte excitability. Caution in digoxin toxicity - calcium can precipitate worsening toxicity.
Step 2 - Intracellular Potassium Shift (Temporary; lowers K⁺ by 0.6-1.5 mEq/L)
| Agent | Dose | Onset | Duration | Effect | Notes |
|---|
| Regular insulin + glucose | Insulin 10 units IV + D50W 1 ampule (or D10W if normoglycemic) | < 15 min | 4-6 h | ↓ 0.6 mEq/L | Most reliable agent; stimulates Na⁺/K⁺-ATPase. Monitor glucose for hours post-therapy |
| Nebulized albuterol | 10-20 mg (adults); weight-based in children | 15-30 min | 2+ h | ↓ 0.5-1.0 mEq/L | Stimulates Na⁺/K⁺-ATPase; additive with insulin (combo lowers ~1.2 mEq/L) |
| Sodium bicarbonate | 1-2 mEq/kg IV | 15-30 min | 1-2 h | Variable | Effective ONLY in acidotic patients; no benefit in non-acidotic hyperkalemia. Risk: volume overload, hypocalcemic tetany/seizures - use cautiously in renal failure |
| IV normal saline | Few hundred mL | Moderate | Short | Modest | Stimulates Na⁺/K⁺-ATPase pump; judiciously in anuric patients |
Step 3 - Potassium Removal from the Body (Definitive)
| Method | Rate of K⁺ Removal | Notes |
|---|
| Hemodialysis | ↓ ~1 mEq/L in first hour, another 1 mEq/L over next 2 hours | Only reliable, experimentally proven method. First choice in life-threatening hyperkalemia with renal failure |
| Furosemide | Variable | Use in patients with intact renal function (e.g., rhabdomyolysis, tumor lysis). No RCTs in acute emergency setting |
| Sodium polystyrene sulfonate (Kayexalate) | Slow (hours) | No longer considered effective or safe within first 4 hours. Risk of intestinal necrosis, especially with sorbitol |
| Patiromer | Slower onset (hours-days) | Newer non-absorbable cation exchanger; useful for chronic/subacute management in CKD + RAAS therapy. Not evaluated in acute hyperkalemia |
| Sodium zirconium cyclosilicate (SZC) | Onset within 1 hour reported | Newer agent; promising for subacute but limited data in acute emergency |
| Peritoneal dialysis | Slower than HD | Alternative when HD unavailable |
Special Situations
- Renal failure (AKI/CKD): K⁺ rises 0.3-0.5 mEq/L per day in oliguric patients - faster in catabolism, sepsis, acidosis, or rhabdomyolysis. Hemodialysis is the cornerstone of definitive therapy. Succinylcholine use is relatively contraindicated.
- Cardiac arrest with suspected hyperkalemia: Treat empirically while resuscitation continues.
- Digoxin toxicity: Avoid calcium (may worsen toxicity); consider digoxin-specific Fab antibodies.
- Metabolic acidosis: Sodium bicarbonate is useful here; correct acidosis to drive K⁺ intracellularly.
- Pseudohyperkalemia: Exclude hemolysis, excessive fist-clenching, thrombocytosis, leukocytosis - confirm with repeat sample and correlate with ECG.
Causes to Treat Simultaneously (Common)
- Renal failure (AKI/CKD) - most common
- Drugs: ACE inhibitors, ARBs, K⁺-sparing diuretics, NSAIDs, heparin, beta-blockers, digoxin, succinylcholine, trimethoprim
- Adrenal insufficiency / Addison's disease / Type 4 RTA
- Cell death: rhabdomyolysis, tumor lysis, hemolysis, burns
- Acidosis (non-anion gap metabolic or respiratory)
Key Points
- Always obtain an ECG immediately - do not wait for labs when hyperkalemia is suspected.
- The three steps must overlap: stabilize membrane first, then shift K⁺, then remove K⁺.
- All shifting measures are temporary (1-6 hours) - definitive removal is essential.
- Calcium gluconate and insulin/glucose are the workhorses of acute management.
- Bicarbonate's role is limited to acidotic patients only.
- A 2025 meta-analysis on novel K⁺ binders (PMID 40542996) confirms patiromer and SZC are effective for chronic management in CKD/heart failure patients on RAAS inhibitors, but are not replacements for acute-phase treatment.
Sources: Rosen's Emergency Medicine, 10e; Schwartz's Principles of Surgery, 11e; Harrison's Principles of Internal Medicine, 22e; Morgan & Mikhail's Clinical Anesthesiology, 7e; Barash's Clinical Anesthesia, 9e.