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Hyperkalemia: Latest Management Guide

Hyperkalemia (a serum potassium K+ > 5.5 mmol/L) is one of the most common and dangerous electrolyte emergencies. It is a “silent killer” that can progress from an asymptomatic lab finding to a fatal arrhythmia within minutes. Effective management requires rapid triage, a clear understanding of the underlying pathophysiology and a structured, step-wise treatment plan.

This guide outlines the core algorithm (Protect, Shift, Remove) and addresses problems you will face on the wards and in intensive care.

Triage & Assessment (The First 10 Minutes)

Your first actions are to determine: 1. Is this real? and 2. Is my patient in danger?

The Triage Questions

  • Is the K+ more than 6.0 mmol/L?
    • Yes: This is moderate-to-severe. The patient needs an immediate 12-lead ECG and attachment to a cardiac monitor.
  • Is the K+ more than 6.5 mmol/L OR are there ECG changes?
    • Yes: This is a life-threatening emergency. Call for senior help, get IV access and start the emergency protocol immediately.
  • Is the high K+ completely unexpected?
    • Yes: Consider pseudohyperkalemia. A hemolyzed (clotted or “difficult”) blood draw can falsely elevate potassium. Quickly send a repeat sample (ideally a venous blood gas, which is faster) but do not delay treatment if the clinical picture (e.g., AKI, ECG changes) fits.

Causes & Clinical Clues

The “Big 3” causes are kidney dysfunction, drugs, and cell breakdown/acidosis. Always check:

  • The Patient: Do they have AKI, CKD, or ESRD? Are they diabetic (DKA)?
  • The Drug Chart: Look for the “K+-Elevating” drugs:
    • ACE Inhibitors (-pril)
    • ARBs (-sartan)
    • Potassium-Sparing Diuretics (Spironolactone, Eplerenone, Amiloride)
    • NSAIDs
    • Trimethoprim
  • The Context: Is there rhabdomyolysis (high CK), tumour lysis syndrome, or significant metabolic acidosis?

ECG Signs: The Progression to Death

Do not wait for this “classic” progression, as patients can arrest at any stage. Any change is an indication for calcium.

  1. Peaked ‘Tented’ T-waves: The earliest sign.
  2. Flat/Absent P-waves & PR Prolongation: Atrial conduction falters.
  3. Widened QRS Complex: Ventricular conduction slows.
  4. Sine Wave Pattern: The pre-terminal rhythm.
  5. Ventricular fibrillation or asystole.

The Emergency Algorithm (Protect, Shift, Remove)

This is the core protocol for any patient with K+ greater than 6.5 mmol/L or any associated ECG changes.

Step 1: PROTECT the Heart (Cardiac Stabilisation)

This is your first and most urgent action. It does not lower serum potassium; it buys you time by stabilising the cardiac membrane.

  • Treatment: Give 30 mL of 10% Calcium Gluconate IV over 5-10 minutes.
  • Monitoring: The patient must be on a cardiac monitor.
  • Repeat? Yes. The effect lasts 30-60 minutes. If ECG changes persist or recur after 10 minutes, repeat the dose.

A common error is giving only 10 mL of 10% calcium gluconate. Recent MHRA (UK) alerts highlight this is a significant underdose. The correct dose is 30 mL.

Step 2: SHIFT the Potassium (Temporary Fix)

This moves potassium from the blood into the cells. This is a temporary measure.

  • Treatment 1: Insulin-Glucose
    • Dose: Give 10 units of short-acting insulin (e.g., Actrapid) with 25g of Glucose.
    • How: This is typically given as 10 units of insulin in 50 mL of 50% Dextrose, or 10 units in 125 mL of 20% Dextrose.
    • Onset: Works in 15-30 minutes.
  • Treatment 2: Salbutamol
    • Dose: Give 10-20 mg of nebulised salbutamol.
    • How: This is a large dose (4-8x a standard neb). It works synergistically with insulin.
    • Caution: Use with care in patients with severe tachyarrhythmias or ischemic heart disease.

CRITICAL SAFETY UPDATE: The insulin-glucose infusion carries a very high risk of iatrogenic hypoglycemia.

  • Monitor: Check capillary blood glucose at 0, 15, 30, 60, 90, and 120 minutes, then hourly for 6 hours.
  • Prevent: If the patient’s pre-treatment BG is <7 mmol/L, start a prophylactic 10% Glucose infusion at 50 mL/hr for 5 hours to prevent a delayed hypoglycemic crash.

Step 3: REMOVE the Potassium (Definitive Treatment)

Shifting K+ is temporary; you must remove the excess from the body.

  • Treatment 1: Diuretics
    • Dose: Give 40-80 mg IV Furosemide.
    • Use: Only effective if the patient is fluid-replete (or overloaded) and has some renal function (i.e., not anuric AKI or ESRD).
  • Treatment 2: Potassium Binders
    • New First-Line: Sodium Zirconium Cyclosilicate (Lokelma). Give 10g PO. It is fast-acting (onset ~1 hour) and highly effective in the acute setting.
    • Old: Calcium Resonium (polystyrene sulfonate) is no longer recommended for acute use. It is slow, poorly tolerated and carries a rare but fatal risk of colonic necrosis.
  • Treatment 3: Dialysis
    • This is the ultimate and most effective way to remove potassium.
    • Indications:
      • Refractory hyperkalemia despite medical therapy.
      • Severe AKI or ESRD (especially anuric patients).
      • Severe acidosis or fluid overload.
    • Action: Call the renal team early. Do not delay.

Advanced Problems & Solutions

This is where clinical nuance changes management.

Problem 1: The Calcium Conundrum (Gluconate vs. Chloride)

  • The Problem: Why 30ml of gluconate? Why not 10ml of chloride?
  • The Solution: It’s about elemental calcium.
    • 10 mL of 10% Calcium Gluconate = ~2.2 mmol of calcium.
    • 10 mL of 10% Calcium Chloride = ~6.8 mmol of calcium.
  • Therefore, 30 mL of 10% Calcium Gluconate is the dose required to provide the same ~6.8 mmol of calcium as 10 mL of Calcium Chloride.
  • When to use which?
    • Gluconate: Preferred for peripheral access as it is less caustic. The 30 mL dose is standard.
    • Chloride: Can be used if you have a central line or a very large, well-running cannula. In a cardiac arrest (PEA with a sine wave), 10 mL of 10% Calcium Chloride is faster to administer and is the treatment of choice.

Problem 2: The Digoxin Toxicity Patient

  • The Problem: The patient has hyperkalemia from severe digoxin toxicity. You’ve heard that giving calcium causes “stone heart” (irreversible cardiac contraction).
  • The Solution: This is a classic medical dilemma.
    • Hyperkalemia (>6.0 mmol/L) in digoxin toxicity is a sign of severe, life-threatening poisoning.
    • The definitive treatment is Digoxin-specific antibody fragments (DigiFab). This is the absolute priority. Call toxicology/ITU/Cardiology immediately.
    • What about calcium? Most modern guidelines (including the European Resuscitation Council) state that if the patient has life-threatening arrhythmias (wide QRS, sine wave) from hyperkalemia, you should still give calcium. The arrhythmia will kill them before the “stone heart” (which is largely theoretical) will.
    • The compromise: If you must give it, give the 30 mL calcium gluconate slowly (e.g., over 30 minutes) while you wait for DigiFab, as this mitigates the risk.

Problem 3: Refractory Hyperkalemia (“It’s not working!”)

  • The Problem: You’ve given calcium, insulin, and salbutamol, but 1 hour later, the repeated K+ is still 7.0 mmol/L and the ECG is still bad.
  • The Solution:
    1. Re-Protect: Give another 30 mL of Calcium Gluconate. The ECG changes are your guide.
    2. Re-Shift: You can repeat the insulin/glucose dose (e.g., another 5-10 units), but be extremely careful with hypoglycemia.
    3. The Real Solution: Escalate. This patient has declared themselves refractory to medical management. Giving multiple doses of insulin just hides the K+ in the cells, making dialysis less effective and risking severe rebound hyperkalemia later. This patient needs urgent haemodialysis. Stop wasting time with shifts; call the renal and ITU teams and escalate.

Problem 4: Choosing Your Binder (Lokelma vs. Patiromer)

  • The Problem: Which one do you start?
  • The Solution:
    • Acute (A&E): Lokelma (Sodium Zirconium Cyclosilicate). Its onset is ~1 hour. It exchanges K+ for Na+. This is your go-to for acute, non-dialysis hyperkalemia. Caveat: The sodium load may be a concern in severe heart failure.
    • Chronic (Clinic): Patiromer. Its onset is ~7 hours (too slow for A&E). It exchanges K+ for Ca2+. Caveat: Can cause hypomagnesemia and constipation.

Summary: Key Takeaways

  1. K+ greater than 6.0? Get an ECG.
  2. K+ greater than 6.5 or ECG Changes? This is an emergency.
  3. First Step: 30 mL of 10% Calcium Gluconate to protect the heart (10 mL is an underdose).
  4. Second Step: 10U Insulin + 25g Glucose to shift K+.
  5. CRITICAL SAFETY: Monitor blood glucose hourly and start a prophylactic 10% glucose infusion to prevent hypoglycemia.
  6. Third Step: Lokelma (acute binder) or Dialysis (refractory/ESRD) to remove K+.
  7. Consultant Calls: Call renal/ITU early for refractory cases, digoxin toxicity, or ESRD patients.

References and Further Readings

  1. UK Kidney Association (UKKA) Guidelines (2023) Link: Clinical Practice Guideline: Management of Hyperkalaemia in Adults

2. European Resuscitation Council (ERC) Guidelines (2021) Link: Section 4: Advanced Life Support – Special Causes (Hyperkalaemia)

3. Resuscitation Council UK: Hyperkalaemia in Adults (2023) Link: Hyperkalaemia in Adults (RCUK)

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