What is the immediate management of severe hyperkalemia, including patients with potassium ≥6.5 mmol/L or electrocardiographic changes?

Immediate Management of Severe Hyperkalemia

For severe hyperkalemia (potassium ≥6.5 mmol/L) or any ECG changes, immediately administer IV calcium gluconate 10% (15–30 mL over 2–5 minutes) to stabilize the cardiac membrane, followed simultaneously by insulin-glucose and nebulized albuterol to shift potassium intracellularly, then initiate definitive potassium removal with loop diuretics or hemodialysis. 1

Step 1: Cardiac Membrane Stabilization (IMMEDIATE – Within 1–3 Minutes)

This is your first action when ECG changes are present or potassium ≥6.5 mEq/L:

• Administer IV calcium gluconate 10%: 15–30 mL over 2–5 minutes 1, 2
• Alternative: Calcium chloride 10%: 5–10 mL (500–1000 mg) over 2–5 minutes if central venous access is available (more potent than gluconate) 1
• Onset: 1–3 minutes; Duration: 30–60 minutes only 1, 3
• Repeat the same dose after 5–10 minutes if ECG abnormalities persist 1, 2

Critical caveats:

• Calcium does NOT lower serum potassium—it only temporarily protects the heart 1, 4
• Never delay calcium while waiting for repeat potassium levels if ECG changes are present—ECG changes indicate urgent need regardless of the exact potassium value 1, 3
• Do not administer calcium through the same IV line as sodium bicarbonate (causes precipitation) 1
• Use calcium cautiously in patients with elevated phosphate (tumor lysis syndrome, renal failure) due to risk of calcium-phosphate tissue precipitation 1
• Continuous cardiac monitoring is mandatory during and after administration 1, 2

Step 2: Shift Potassium Into Cells (15–30 Minutes – Administer ALL Simultaneously)

Give all three agents together for maximum effect:

Insulin-Glucose (First-Line)

• 10 units regular insulin IV push + 25 g dextrose (50 mL D50W) 1, 2
• Lowers potassium by 0.5–1.2 mEq/L 1
• Onset: 15–30 minutes; Peak: 30–60 minutes; Duration: 4–6 hours 1, 5
• Never give insulin without glucose—hypoglycemia can be fatal 1, 2
• Monitor blood glucose closely; patients with low baseline glucose, no diabetes, female sex, or renal impairment are at higher risk of hypoglycemia 1

Nebulized Albuterol (Additive Effect)

• 10–20 mg albuterol in 4 mL nebulized over 10–15 minutes 1, 2
• Lowers potassium by 0.5–1.0 mEq/L 1
• Onset: ~30 minutes; Duration: 2–4 hours 1
• Can be repeated every 2 hours if needed 1
• The combination of insulin-glucose plus albuterol is more effective than either agent alone 1, 5

Sodium Bicarbonate (ONLY with Metabolic Acidosis)

• 50 mEq IV over 5 minutes ONLY if pH < 7.35 AND bicarbonate < 22 mEq/L 1, 2
• Onset: 30–60 minutes 1
• Do NOT use without documented metabolic acidosis—it is ineffective and wastes time 1, 3
• Must not be given through the same line as calcium 1

Step 3: Remove Potassium from the Body (Hours – Definitive Treatment)

Loop Diuretics (If Adequate Renal Function)

• Furosemide 40–80 mg IV when eGFR > 30 mL/min and patient is non-oliguric 1, 4
• Effectiveness depends on sufficient urine output 1
• Titrate to maintain euvolemia, not primarily for potassium management 3

Hemodialysis (Gold Standard for Severe Cases)

Absolute indications for urgent hemodialysis: 1, 4

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

In hemodynamically unstable patients (hypotension, vasopressor requirement), use continuous renal replacement therapy (CRRT) instead of intermittent hemodialysis to minimize rapid fluid shifts 1

Potassium Binders (Sub-Acute Management)

• Sodium zirconium cyclosilicate (SZC/Lokelma): 10 g three times daily for 48 hours, then 5–15 g once daily; onset ≈1 hour 1, 3
• Patiromer (Veltassa): 8.4 g once daily with food, titrated up to 25.2 g daily; onset ≈7 hours; separate from other oral meds by ≥3 hours 1, 3
• Avoid sodium polystyrene sulfonate (Kayexalate) due to bowel necrosis, colonic ischemia, and lack of efficacy data 1, 6

ECG Changes by Potassium Level

Recognize the progression to anticipate cardiac arrest: 1, 2

• > 5.5 mEq/L: Peaked/tented T waves (earliest sign)
• 6.0–6.4 mEq/L: Flattened or absent P waves, prolonged PR interval
• > 6.5 mEq/L: Widened QRS complex, deepened S waves
• ≥ 7–8 mEq/L: Sine-wave pattern, idioventricular rhythms, ventricular fibrillation, or asystole

Important: ECG findings are highly variable and less sensitive than laboratory tests—absence of ECG changes does not rule out dangerous hyperkalemia 3, 2, 7

Medication Management During Acute Episode

Hold the following when potassium > 6.5 mEq/L: 1, 3

• RAAS inhibitors (ACE-I, ARB, mineralocorticoid receptor antagonists)
• NSAIDs
• Potassium-sparing diuretics
• Trimethoprim-containing antibiotics
• Heparin
• Beta-blockers
• Potassium supplements and salt substitutes

After resolution (potassium < 5.0 mEq/L): 1, 3

• Restart RAAS inhibitors at a lower dose—do NOT permanently discontinue these life-saving medications
• Initiate a potassium binder (SZC or patiromer) to enable continuation of RAAS therapy, which provides mortality benefit in cardiovascular and renal disease

Monitoring Protocol

Acute Phase

• Re-measure serum potassium 1–2 hours after insulin-glucose or albuterol administration 1, 2
• Continue checks every 2–4 hours until stable 1
• Obtain repeat ECG to confirm resolution of cardiac abnormalities 1, 2
• Monitor blood glucose closely after insulin 2

Post-Acute Phase

• Check potassium within 1 week after initiating or escalating RAAS inhibitors 1, 3
• Reassess 7–10 days after starting a potassium binder 1, 3
• Tailor monitoring frequency to individual risk factors (eGFR, heart failure, diabetes, prior hyperkalemia episodes) 1, 3

Critical Pitfalls to Avoid

• Do not delay calcium administration while waiting for repeat lab confirmation if ECG changes are present—ECG changes indicate urgent need 1, 3
• Never give insulin without glucose—hypoglycemia can be life-threatening 1, 2
• Remember that calcium, insulin, and beta-agonists are temporizing measures only—they do NOT remove potassium from the body 1, 4
• Do not use sodium bicarbonate without metabolic acidosis—it is ineffective and wastes time 1, 3
• Always verify hyperkalemia with a second sample when possible to rule out pseudohyperkalemia from hemolysis during phlebotomy 1, 2
• Recognize that absent or atypical ECG changes do not exclude the necessity for immediate intervention 5, 7