What is the acute treatment for severe hyperkalaemia with potassium >6.5 mmol/L or ECG abnormalities?

Treatment of Severe Hyperkalemia (K⁺ >6.5 mmol/L or ECG Abnormalities)

For severe hyperkalemia with potassium >6.5 mmol/L or any ECG changes, immediately administer IV calcium gluconate 15-30 mL over 2-5 minutes to stabilize the cardiac membrane, followed simultaneously by insulin 10 units with 25g dextrose and nebulized albuterol 10-20 mg to shift potassium intracellularly, then initiate definitive potassium removal with loop diuretics or hemodialysis. 1, 2, 3

Immediate Cardiac Membrane Stabilization (First Priority)

Administer calcium within 1-3 minutes of recognizing ECG changes—do not wait for repeat potassium levels. 1, 3

• Calcium gluconate 10%: 15-30 mL IV over 2-5 minutes (preferred for peripheral access) 1, 3
• Calcium chloride 10%: 5-10 mL IV over 2-5 minutes (more potent, requires central access) 1
• Onset of action: 1-3 minutes, duration: 30-60 minutes 1, 3
• Repeat the dose if ECG does not improve within 5-10 minutes 1
• Critical caveat: Calcium does NOT lower serum potassium—it only protects the heart temporarily 1, 3, 4
• Continuous cardiac monitoring is mandatory during and after administration 1

Special Precautions for Calcium

• Never infuse calcium through the same IV line as sodium bicarbonate—precipitation will occur 1
• In tumor lysis syndrome with elevated phosphate, use calcium cautiously due to calcium-phosphate precipitation risk 1

Intracellular Potassium Shift (Administer Simultaneously)

Insulin-Glucose Therapy

• 10 units regular insulin IV push + 25g dextrose (50 mL D50W) 1, 3, 4
• Lowers potassium by 0.5-1.2 mEq/L within 30-60 minutes, duration 4-6 hours 1, 3
• Never give insulin without glucose—hypoglycemia can be fatal 1, 3
• Monitor blood glucose closely after administration 1, 3
• Can be repeated every 4-6 hours if hyperkalemia persists, with careful glucose and potassium monitoring 1

Beta-Agonist Therapy

• Nebulized albuterol 10-20 mg in 4 mL over 10-15 minutes 1, 3, 4
• Lowers potassium by 0.5-1.0 mEq/L within 30 minutes, duration 2-4 hours 1, 3
• Combined insulin-glucose plus albuterol is more effective than either alone 1, 3
• Can be repeated every 2 hours if needed 1

Sodium Bicarbonate (Only with Metabolic Acidosis)

• 50 mEq IV over 5 minutes ONLY if pH <7.35 and bicarbonate <22 mEq/L 1, 3, 4
• Onset: 30-60 minutes 1
• Do NOT use without documented metabolic acidosis—it is ineffective and wastes time 1, 3

Definitive Potassium Removal (Within Hours)

Loop Diuretics (If Adequate Renal Function)

• Furosemide 40-80 mg IV for patients with eGFR >30 mL/min who are non-oliguric 1, 4
• Increases renal potassium excretion by stimulating flow to collecting ducts 1

Hemodialysis (Most Reliable Method)

Hemodialysis is the gold standard for severe hyperkalemia and should be initiated urgently in the following situations: 1, 4, 5

• Serum potassium >6.5 mEq/L unresponsive to medical therapy 1
• Oliguria or anuria 1
• End-stage renal disease 1, 4
• Ongoing potassium release (tumor lysis syndrome, rhabdomyolysis) 1
• Severe renal impairment (eGFR <15 mL/min) 1
• Persistent ECG changes despite medical management 1

In hemodynamically unstable patients, continuous renal replacement therapy (CRRT) is preferred over intermittent hemodialysis to minimize rapid fluid shifts and intradialytic hypotension 1

Potassium Binders (Sub-Acute Management)

• Sodium zirconium cyclosilicate (SZC/Lokelma): 10g three times daily for 48 hours, then 5-15g once daily 1, 6
  • Onset: ~1 hour (suitable for urgent scenarios) 1
• Patiromer (Veltassa): 8.4g once daily with food, titrated up to 25.2g daily 1, 6
  • Onset: ~7 hours (for sub-acute/chronic control) 1
  • Must be separated from other oral medications by ≥3 hours 1
• Avoid sodium polystyrene sulfonate (Kayexalate)—risk of bowel necrosis, colonic ischemia, and limited efficacy 1, 6

Medication Management During Acute Episode

Hold Immediately When K⁺ >6.5 mEq/L:

• RAAS inhibitors (ACE inhibitors, ARBs, mineralocorticoid receptor antagonists) 1, 2
• NSAIDs 1, 2
• Potassium-sparing diuretics 1, 2
• Trimethoprim-containing agents 1
• Heparin 1
• Beta-blockers 1
• Potassium supplements and salt substitutes 1, 2

After Acute Resolution:

• Restart RAAS inhibitors at a lower dose once potassium <5.0 mEq/L 1, 2
• Initiate a potassium binder (SZC or patiromer) to enable continuation of life-saving RAAS therapy 1, 2
• These medications provide mortality benefit in cardiovascular and renal disease 1, 2

Monitoring Protocol

Acute Phase:

• Re-measure serum potassium 1-2 hours after insulin/glucose or beta-agonist therapy 1, 3
• Continue potassium checks every 2-4 hours until stable 1, 3
• Obtain repeat ECG to confirm resolution of cardiac changes 1, 3
• Monitor blood glucose closely to prevent hypoglycemia 1, 3

Post-Acute Phase:

• Check potassium within 1 week after initiating or escalating RAAS inhibitors 1
• Reassess 7-10 days after starting a potassium binder 1
• Individualize monitoring frequency based on eGFR, heart failure status, diabetes, or prior hyperkalemia episodes 1

Critical Pitfalls to Avoid

• Do NOT delay calcium administration while awaiting repeat potassium levels when ECG changes are present—ECG abnormalities indicate urgent need regardless of exact potassium value 1, 3
• Never give insulin without glucose—hypoglycemia can be fatal 1, 3
• Recognize that calcium, insulin, and beta-agonists are temporizing measures only—they do NOT remove potassium from the body 1, 3, 4
• Do NOT use sodium bicarbonate without documented metabolic acidosis—it is ineffective without acidosis 1, 3
• Do NOT permanently discontinue RAAS inhibitors—use potassium binders to maintain these life-saving medications 1, 2
• Failure to initiate concurrent potassium-lowering therapies will result in recurrent life-threatening arrhythmias within 30-60 minutes after calcium's effect wears off 1

ECG Changes Requiring Immediate Treatment

Any of the following ECG findings demand emergency treatment irrespective of measured serum potassium level: 1, 2, 3

• Peaked/tented T waves (earliest sign, typically K⁺ >5.5 mEq/L) 1, 3
• Flattened or absent P waves 1, 3
• Prolonged PR interval 1, 3
• Widened QRS complex 1, 3
• Sine-wave pattern 1
• Idioventricular rhythms, ventricular fibrillation, or asystole 1

ECG findings are highly variable and less sensitive than laboratory tests—absence of ECG changes does NOT rule out dangerous hyperkalemia. 1, 3