Hyperkalaemia

Disclaimer

These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline. 

Read the full PCH Emergency Department disclaimer.

Aim 

To guide staff with the assessment and management of acute hyperkalaemia.

Definition

Hyperkalaemia is defined as a serum potassium (K+) of more than 5.5 mmol/L.

Background

  • Serum K+ over 6.5 – 7 mmol/L, especially when associated with ECG changes is potentially life-threatening, and should be treated as an emergency.
  • Cardiac toxicity is enhanced by hypocalcaemia, hyponatraemia or acidosis, and patients with these abnormalities may experience complications at lower potassium levels.

Key points

In children, severe hyperkalaemia may result from:
  • drug ingestions (e.g. digoxin, ACE-inhibitors, oral potassium)
  • acute renal failure
  • massive tissue damage (major trauma or burns, tumour lysis syndrome, haemolysis)
  • severe metabolic acidosis
  • adrenogenital syndromes.

Assessment

  • Perform an ECG
  • Exclude erroneous high potassium (pseudo-hyperkalaemia) due to haemolysis during collection or transport of the specimen.

History

Clinical features of hyperkalaemia relate to potassium’s effect on cellular membrane polarisation.

  • Early symptoms include nausea, vomiting and paraesthesia.

Examination

Assess for:
  • muscle weakness, progressing to flaccid paralysis and respiratory failure.
  • cardiac conduction disturbance, resulting in wide complex tachycardia, ventricular fibrillation and circulatory failure.

Investigations

ECG Changes

  • In acute hyperkalaemia, cardiac conduction disturbance results in ECG changes which correlate roughly with serum K+ levels.

K+ > 6 mmol/L

ECG - Potassium greater than 6mmol

  • Tall, symmetrical peaked T-waves

K+ > 7.5 mmol/L

ECG - potassium greater than 7.5mmol

  • PR interval lengthens (1st degree AV block)
  • Widened QRS (intraventricular block)

K+ > 9 mmol/L

ECG - potassium greater than 9mmol

  • Absent P-wave
  • Pre-arrest, QRS and T-waves merge to form a sine wave

Management

  • Hyperkalaemia should be treated when serum K+ is over 7 mmol/L, or at levels lower than this if ECG changes are present.
  • Emergency management of hyperkalaemia should include early consultation with the Paediatric Critical Care (PCC).

Initial management

Step 1: Protect the myocardium from the effects of hyperkalaemia

  • Discontinue any potassium supplement and potassium-containing IV fluids.
Calcium
  • Doesn't lower the serum K+, but is cardioprotective in that it stabilises the myocardium, reducing the risk of arrhythmias
  • Contraindicated in digitalis toxicity and hypercalcaemia
  • Dose can be repeated after 15 minutes if ECG is still abnormal
  • Can be given as either calcium gluconate or calcium chloride.
    The calcium content of each is different – take care with dosing.
  • 10% calcium gluconate 0.5mL/kg (maximum 20mL) IV over 2-5 minutes 
(10% calcium gluconate = 2.2mmol in 10ml)

or

  • 10% calcium chloride 0.2mL/kg (maximum 10mL) IV over 2-5 minutes

Step 2: Lower the serum potassium level urgently

  • Note: All of these methods act by shifting potassium intracellularly, thereby reducing the serum K+ level. None of these methods actually reduce total body potassium. 
  • These methods are not listed in specific treatment order – the clinical situation and clinician decision will guide choice of management

Salbutamol

  • Nebulised or intravenous
  • As effective as glucose and insulin
  • Acts within 60 minutes and lasts about 6 hours.

Nebulised:

5 mg (child > 5 years) or 
2.5mg (child < 5 years)

IV:

Use for severe hyperkalaemia – discuss with senior doctor before administering: 
  • 4 microgram/kg over 20 minutes (may be repeated after 2 hours)

Glucose

  • Similar onset and duration of effect to salbutamol
  • Patients endogenous insulin drives potassium intracellularly
  • 10% glucose at 2mL/kg slow IV bolus

Then commence:

  • 5% glucose + sodium chloride 0.9% at maintenance rate
  • Monitor blood glucose every 30 minutes 
  • Higher glucose concentration solutions will be needed if hypoglycaemia occurs.

Insulin

(only to be used with IV glucose if hyperglycaemia is an issue)

  • Discuss with a senior doctor before commencing
  • Insulin is only to be given once the glucose infusion has been commenced
  • Onset of action 15 minutes
  • Monitor glucose every 30-60 minutes.
  • Insulin short acting infusion at 0.1 unit/kg/hr
  • Make up 50 units of Actrapid (or Humulin R) in 50mL sodium chloride 0.9% (1unit/mL).
  • Prime line with 20mL of solution before commencing the infusion.  

Sodium bicarbonate

  • Discuss with an Emergency Department senior doctor or PCC prior to use.
  • Not routine, but can be used in an emergency even in the absence of metabolic acidosis.
  • Do not administer via the same line as calcium.
  • Contraindicated in alkalosis, hypernatraemia.
  • Any hypocalcaemia must first be corrected.
  • Infuse at 1 mmol/kg intravenous over 30 minutes.

Furosemide
(Frusemide)

  • Consider (in patients in fluid overload in consultation with  PCC)

1mg/kg (IV)

Step 3: Promote elimination of potassium from the body

Sodium polystyrene sulfonate
(Resonium-A)

or

Calcium polystyrene sulfonate
(Calcium Resonium)

  • Cease Resonium treatment when the serum potassium is less than 5 mmol/L (to avoid hypokalaemia).
  • Do not use if the patient has ileus, has had recent abdominal surgery or perforation.
  • Do not use Sodium polystyrene sulfonate if the patient is hypernatraemic. 

* Consider the use of Calcium Resonium in these patients.

*Administration and dosing are for Resonium-A


Oral dose (onset 4-6 hours): 
  • 0.5 - 1g/kg (max 60g daily). 
  • Administer in a small volume of water or lactulose.
Rectal dose (onset 1 hour): 
  • 0.5 - 1 g/kg (max 30g daily). 
  • To administer, mix each 1g of resin with 5mL of water or 10% glucose.  
  • Irrigate the colon after 8 to 12 hours to remove the resin.

Dialysis

  • Peritoneal dialysis or haemodialysis

Nursing care

  • Continuous ECG monitoring is required due to the risk of lethal dysrhythmias.



Reviewer/Team: Meredith Borland (ED Director), Dennis Chow (ED Consultant), Deirdre Speldewinde (ED Consultant), Gabrielle Anstey (ED CNS), Craig Hasler (ED CNM), John Ailakis (Pharmacy)
Last reviewed: Aug 2018


Review date: Au 2021
Endorsed by:

Drugs & Therapeutics Committee
Date:  Sep 2018


This document can be made available in alternative formats on request for a person with a disability.