Hyperkalaemia

  • See also:  Resuscitation clinical practical guidelines.

    Background

    • Hyperkalaemia: serum K+ > 5.5 mEq/L, (N range = 3.5-5.0 mEq/L), or ? 6.0mEq/L in neonates.
    • Hyperkalaemia is potentially life threatening, and can result in cardiac arrhythmias and sudden death.

    Causes:

    • Hyperkalaemia as an artefact of collection process or technique
    • Decreased excretion (frequent cause of hyperkalaemia)
      o Renal diseases: Acute/chronic renal failure, renal anomaly (eg. Sickle cell)
      o Adrenal mineralocorticoid deficiency
    • Transcellular shift
      o Acidosis  Eg. Diabetic acidocetosis, lactic acidosis
    • Increased production (Most often if in association with renal dysfunction)
      o Extensive trauma, Rhabdomyolysis (Crush injury, convulsion, infection), Haemolysis, Tumour lyses syndrome, Burns
    • Exogenous source
      o Iatrogenic potassium administration (oral, IV)
      o Increased ingestion
      o Massive Transfusion
    • Medication
      o Eg. NSAID, trimethoprim, heparin, chemotherapy, K -sparing diuretic, ACE inhibitor, b-blockers, succhinycholine, digoxin, mannitol

    Assessment:

    History and examination:

    • Look for possible causes (see above)
    • Hyperkalaemia can be initially asymptomatic or can presents with severe symptoms/signs:
      • Respiratory depression
      • Palpitations, Arrhythmia, Cardiac arrest
      • Paresthesia, flaccid paralysis
      • Ileus
    • Confirm that potassium in IV fluids and oral potassium supplement are stopped.
    • Assess the patient's medication to stop drugs that increase potassium or reduce its excretion. 

    Investigation and monitoring:

    Note: Patients with moderate or severe hyperkalaemia need continuous cardiac monitoring and IV access

    • Level of potassium should be confirmed with a second sample.
      • If patient present renal dysfunction (renal failure or other renal disease), assume potassium level correct until proven otherwise
      • Acute increases of potassium means higher risk of arrhythmia.
    • Do an ECG to identify conduction disturbance:
      • Peaked T wave (early)
      • Prolonged PR, flattening of P wave, widening of QRS(increased risk of arrhythmia)
      • Absence of P wave, Sine wave (fusion of QRS and T wave)
      • Ventricular arrhythmia, asystole

    Note: A normal ECG does not exclude risk for arrhythmia as life threatening arrhythmia can occur without warning

    • Complete your investigation and search for causes of hyperkalaemia:
      • Urea, creatinine and electrolytes
      • Glucose
      • Venous blood gas
      • +/- Urine analysis and urinary electrolytes
    • Consider other investigations depending on cause:
      • CK
      • Cortisol, aldosterone and hormonal precursor levels (particularly if hypoNa+)
      • Level of digoxin (if relevant)

    Treatment: (flowchart)

    Hyperkalaemia - Treatment: (flowchart)

    If pulseless arythmia :  Resuscitation Clinical Practical Guidelines

    ***Stop any source of potassium intake (IV fluid, parenteral alimentation, dietary supplement (including NGT feeding)) and any medication potassium sparing

    Severe hyperkalaemia

    - K+ >7.0 mEq/L or at risk of increasing and/or
    - Patient symptomatic and/or
    - ECG disturbance:

    Consider hydrocortisone 1-2 mg/kg IV to consider if suspicion of  adrenal insufficiency (guildeline)

    Moderate hyperkalaemia

    - K 6-7
    - Asymptomatic
    - Normal ECG

    Mild hyperkalaemia

    - K >5.5
    - Asymptomatic
    - Normal ECG

    • Consider no treatment
    • Stop K supplements
    • Recheck result
    • Salbutamol neb
    • Polystyrene sulfonate PR or oral ( resonium)
    • Bicarbonate IV if metabolic acidosis

    Therapies:

    Calcium: 

    2 solutions :

    • Calcium Gluconate 10%: 0.5 ml/kg slow IV injection
      o 2-5 minutes  if unstable, over 15-20min if stable (Max: 20ml)
      o Preferable if only peripheral line available
      OR
    • Calcium Chloride 10% : 0.1-0.2 ml/kg slow IV injection (as above) (Max : 10ml)
      Note: Give under cardiac monitoring, discontinue if HR dropping significantly
      Avoid extravasations
      NOT to be given simultaneously with bicarbonate
      NOT to be given if digital toxicity
      Onset of Action: <3 minutes, should see normalisation of ECG. If not: repeat dose (twice)
      Duration: ~30 minutes

    Salbutamol:

    • Salbutamol: nebulisation
      • Less than 25kg : 2.5 mg neb q 1-2h
      • More than 25kg : 5mg  neb (Adu max 10-20mg) q 1-2h
    • Salbutamol : IV *Only if severe hyperkalaemia after discussion with senior doctor from tertiary center with monitoring for tachycardia

    Onset of Action: 30 minutes, should reduced intravascular K+ of 0.5-1.5mmol/L
    Duration: 2-3 hours

    Insulin/glucose 

    to be given at the same time

    If severe hyperkalaemia:

    • Dextrose 10% :  5ml/kg IV bolus (if no hyponatremia)
    • Insulin short action: 0.1 U/kg IV bolus  (Max 10 units)

    Then followed by infusion insulin/glucose (see below)
     
    If moderate hyperkalaemia:

    • Dextrose 10% IV at maintenance with 0.9% sodium chloride (normal saline)
    • Insulin short action infusion : 0.1 U/kg/h IV

    Note: Close monitoring of glucose every 30-60 minutes

    Onset of Action: 15 minutes, should reduced intravascular K+, reduction of 0.5-1.5mmol/L
    Duration:  peak 60 minutes, 2-3hours

    Bicarbonate 
    In metabolic acidosis only.

    Severe hyperkalamia and metabolic acidosis

    • Sodium Bicarbonate 8.4% 1mmol/ml : 1-3ml/kg IV over 5 minutes

    Mild to moderate hyperkalaemia and metabolic acidosis:

    • Sodium Bicarbonate 8.4% 1mmol/ml : 1ml/kg in slow IV infusion over 30 minutes

    Note: NOT to give simultaneously with Calcium
    Onset of Action: 30-60 minutes, should reduced intravascular K+ of 0.5
    Duration: 2-3 hours

    Dialysis

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

    Resonium

    Mild effect, multiple doses necessary, may be used as long term agent

    • Polystyrene sulfonate (Resonium) 0.3-1g/kg q 6h (Max 15-30g) PR or oral (with lactulose)

    Note:  NOT to be used if ileus, recent abdominal surgery, perforation, hypernatremia
    Onset of Action:  1h PR, 4-6h oral, should reduced intravascular K+ of 0.5-1 mEq/L
    Duration: variable

    Consider consultation with local paediatric team:

    - Any child with moderate or severe hyperkalamia
    - Underlying medical cause - eg renal abnormalities

    When to consider transfer to tertiary centre:

    - Any child with severe hyperkalamia
    - Any child requiring dialysis
    - Child requiring care beyond the comfort level of the hospital.

    For emergency advice and paediatric or neonatal ICU transfers, call the Paediatric Infant Perinatal Emergency Retrieval (PIPER) Service: 1300 137 650.

    Information Specific for RCH

    Consider early ICU review if severe hyperkalaemia.
    Notify child's home team (especially Renal) 

     

     

     

    Last updated March 2016