See also

Basic Paediatric ECG interpretation
Electrolyte abnormalities
Intravenous fluids
Resuscitation: Care of the seriously unwell child
Resuscitation: Hospital management of cardiopulmonary arrest

Key points

1. Moderate or severe hyperkalaemia can cause life-threatening arrhythmias and cardiac arrest. Perform an ECG and commence cardiac monitoring
2. Stop any medications or fluids which cause hyperkalaemia
3. Seek specialist advice for children with underlying renal disease or complex co-morbidities

Background

Hyperkalaemia:

• Serum potassium >5.5 mmol/L (normal range = 3.5-5.0 mmol/L), or 
• Serum potassium >6.0 mmol/L in neonates

Hyperkalaemia is potentially life threatening, and can result in arrhythmias and sudden death

Causes of hyperkalaemia

Assessment

History and examination

Hyperkalaemia can be initially asymptomatic or can present with severe symptoms and signs:

• Nausea, vomiting
• Fatigue
• Paraesthesia, muscle weakness, reduced tendon reflexes, flaccid paralysis
• Ileus
• Respiratory depression/hypoventilation
• Palpitations, arrhythmia, syncope, cardiac arrest
  

Assess for possible causes (see table above)

Management

Investigations

Children with moderate or severe hyperkalaemia need continuous cardiac monitoring and IV access

Confirm potassium level with a second sample

• If initial potassium level is critically high and hyperkalaemia is likely based on clinical scenario, initiate treatment before waiting for a repeat venous sample result
• Acute increase of potassium is associated with higher risk of arrhythmia

Do an ECG to identify conduction disturbance (see Additional information and Basic paediatric ECG interpretation)

• Tall/peaked T wave (early)
• Prolonged PR interval
• Flattening, widening or loss of P wave
• Widening of QRS (increased risk of arrhythmia)
• Bradyarrhythmia, conduction blocks
• Severe hyperkalaemia: sine wave (fusion of QRS and T wave), ventricular arrhythmia, pulseless electrical activity, asystole

A normal ECG does not exclude risk for arrhythmia. Life threatening arrhythmia can occur without warning

Other investigations

• Urea, creatinine and electrolytes
• Blood glucose level
• Venous blood gas
• +/- urine analysis and urinary electrolytes
• Consider other investigations based on suspected underlying cause:
  • CK
  • Cortisol, aldosterone and hormonal precursor levels (particularly if hyponatraemia)
  • Digoxin level (if relevant)

Treatment

Goals of treating hyperkalaemia are

1. Correct underlying cause
• Discontinue any potassium-containing fluids or medications
2. Stabilise cardiac membrane in life-threatening hyperkalaemia with ECG changes: calcium IV
3. Reduce serum potassium levels
   • Shift potassium into cells: salbutamol nebulised, insulin and glucose IV
   • Remove potassium from body: resonium PR
     
     

Medications

Calcium

Stabilises myocardium in life-threatening hyperkalaemia (does not reduce potassium)

2 options

• Calcium gluconate 10%: 0.15 mmol/kg, maximum 6.6 mmol
  (0.68 mL/kg, max 30 mL), slow IV/intraosseous injection over 2-5 minutes if unstable, 15-20 minutes if stable
  • Preferable if only peripheral line available, as less irritant to veins

• Calcium chloride 10%: 0.14 mmol/kg, maximum 6.8 mmol
  (0.2 mL/kg, max 10 mL) slow IV/intraosseous injection over 2-5 minutes if unstable, over 15-20 minutes if stable
  
  

Continuous cardiac monitoring. Discontinue if heart rate drops significantly

• Monitor closely for extravasation
• Not to be given simultaneously with bicarbonate
• Not to be given if digoxin toxicity
• Onset of action: <3 minutes. Should see normalisation of ECG. If not, repeat dose (twice) or IV infusion titrated to response
• Duration of action: approximately 30 minutes

Salbutamol

Salbutamol via nebuliser

• ≤25 kg: 2.5 mg neb 1-2 hourly
• >25 kg: 5 mg neb (max 10-20 mg) 1-2 hourly
  
  
• Onset of action: 30 minutes
• Duration of action: 2-3 hours

Only consider salbutamol IV if severe hyperkalaemia AND after discussion with senior clinician. Monitor for tachycardia

Insulin and glucose (give together)
Severe hyperkalaemia

• Glucose 10% 5 mL/kg IV bolus (if no hyponatraemia)
• Insulin short acting (eg Actrapid®) 0.1 unit/kg IV bolus (max 10 units)
• Followed by insulin/glucose infusion (see below)

Moderate hyperkalaemia

• Glucose 10% with 0.9% sodium chloride IV at maintenance rate
• Insulin short acting (eg Actrapid®) infusion: 0.1 unit/kg/hour IV

Insulin administration:

Insulin vials are highly concentrated in relation to dosage and have a high risk of medication error 

To safely prepare the insulin dose, first dilute 10 units of insulin (= 0.1 mL) to a total of 10 mL with sodium chloride 0.9% to make a final concentration of 1 unit/mL. Withdraw the prescribed insulin dose from this 1 unit/mL solution

• Close monitoring of glucose every 30-60 minutes
• Onset of action: 15 minutes
• Duration:  peak 60 minutes, 2-3 hours

Bicarbonate
In metabolic acidosis only

• Severe hyperkalaemia and metabolic acidosis
  • Sodium bicarbonate 8.4% 1 mmol/mL: administer 1-3 mmol/kg (1-3 mL/kg) IV over 5 minutes

• Mild to moderate hyperkalaemia and metabolic acidosis
  • Sodium bicarbonate 8.4% 1 mmol/mL: administer 1 mmol/kg (1 mL/kg) slow IV infusion over 30 minutes

• Do NOT give simultaneously with calcium
• Onset of action: 30-60 minutes
• Duration: 2-3 hours

Polystyrene sulfonate resins (resonium)

• Mild effect, multiple doses necessary, may be used as long-term agent
• Sodium polystyrene sulfonate (Resonium A®) or calcium polystyrene sulfonate (Calcium Resonium®) 0.5-1 g/kg 6 hourly (max 30 g) PR or oral (with lactulose)
• Not to be used if ileus, recent abdominal surgery, perforation, or hypernatraemia
• Repeat if required
• Separate oral administration from other oral medications by at least 3 hours
• Onset of action:  1 hour PR, 4-6 hours oral
• Duration: variable

Dialysis
To be organised with local paediatric renal or intensive care team. Transfer to tertiary centre

Consider consultation with local paediatric team when

• All children with moderate or severe hyperkalaemia
• Underlying medical cause eg renal abnormalities

Consider transfer when

• All children with severe hyperkalaemia
• All children requiring dialysis  
• Child requiring care beyond the comfort level of the hospital

For emergency advice and paediatric or neonatal ICU transfers, see Retrieval Services

Consider discharge when

• Potassium level is normal and stable
• Child is asymptomatic with normal ECG
• Cause of hyperkalaemia identified and treated adequately

Additional information

ECG: peaked T waves

ECG: prolonged PR interval, broad bizarre QRS complexes, peaked T waves

ECG: bradyarrhythmia, slow junctional rhythm, peaked T waves

ECG: huge, peaked T waves, sine wave appearance

Last updated August 2024