HYPERKALAEMIA

Recognition

Definition (Advanced Life Support Seventh Addition Resuscitation Council (UK))

• There is no general consensus on the definition of hyperkalaemia but The Resus Council defines it as when “The blood potassium increases above 5.5 mmol/L”

Causes

• Kidney disease (acute kidney injury, chronic kidney disease)
• Drugs
  • Drugs that reduce renal K⁺ excretion
    • K⁺ sparing diuretics
      • Amiloride
      • Spironolactone
    • Angiotensin Converting Enzyme inhibitors (ACEi)
  • Nephrotoxic drugs
    • Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)
  • K⁺ supplements
    • Fluids with added K⁺
    • Feed
• Rhabdomyolysis
• Metabolic acidosis
• Endocrine disorders
  • Addisons Disease
  • Diabetic Ketoacidosis
• Haemolysis

History

• If possible, ascertain if patient has:
  • Previous admissions with chest pain or cardiac conditions
  • Any operations or treatment for cardiac conditions
  • Any allergies

General symptoms

• Shortness of breath (dyspnoea)
• Chest pain
• Palpitations
• Malaise

General Signs

• Tachypnoea
• Tachycardia/Bradycardia

Severity (Advanced Life Support Seventh Addition Resuscitation Council (UK))

• Mild - K⁺ 5.5 - 5.9 mmol/L
• Moderate - K⁺ 6.0 - 6.4 mmol/L
• Severe - K⁺ ≥ 6.5 mmol/L

Initial Assessment and Investigations

• ABCDE assessment
• Assess patient’s airway
• Monitor oxygen saturations and respiratory rate
  • If patient is hypoxic give Oxygen (O₂) to achieve target saturations. Initially give 15 L/min via a reservoir mask if the patient is acutely unwell
• Target saturations:
  • 94 - 98% for patients not at risk of hypercapnic respiratory failure
  • 88 - 92% for patients at risk of hypercapnic respiratory failure due to conditions such as Chronic Obstructive Pulmonary Disease (COPD)
• Examine patient’s chest
• Obtain intravenous access by placing 2 large bore cannulae in the antecubital fossa. Take blood to check Full Blood Count (FBC), Urea and Electrolytes (U&Es), Liver Function Tests (LFTS), and Venous Blood Gas (VBG)
• Check Capillary Refill Time (CRT) - hold for five seconds and refilling should occur in 3 seconds
• Assess pulse rate, rhythm and character
• Monitor heart rate and blood pressure
• Listen to patient’s heart sounds
• 12 lead Electrocardiogram (ECG)
  • Changes seen
    • Flattened P waves
    • Tall tented T waves
    • S and T wave merging
    • Widened QRS
    • Tachycardia/Bradycardia
    • Cardiac arrest
• If ECG abnormalities are seen attach patient to cardiac monitoring
• Call for senior help
• Check urine output and consider catheterisation
• Intravenous (IV) fluids as required by clinical picture and balanced with patients’ risk of fluid overload. See more details in the “Circulation” Chapter in the “Response” Section under “Fluid Challenge”
• Check pupils are equal and reactive
• Assess Glasgow Coma Scale or ACVPU using the NEWS2 chart
• Check patient’s temperature and blood sugar
• Examine patient’s abdomen and legs
• Consider venous thromboembolism prophylaxis

Response

Management

• Dependent on severity of hyperkalaemia
  • Mild
    • Remove cause
    • Monitor
  • Moderate
    • Treatment guided by clinical case and presence of ECG changes
  • Severe
    • Emergency treatment required
• Pharmacological
  • Stabilise myocardium
    • 30 ml 10% Calcium Chloride IV or 10 ml 10% Calcium Chloride over 5 – 10 mins. Effects seen in approximately 3 mins by an improvement in the ECG appearance. If no change is seen, the dose should be repeated after 5 – 10 mins
  • Move K⁺ into cells
    • 10 units of soluble Insulin with 50 mls of 50% glucose. This is given via a syringe driver over 15 minutes. (8 units of soluble insulin recommended for patients with kidney failure)
    • Nebulise 5 mg Salbutamol
  • Consider Removal K⁺ from the body
    • Calcium Resonium 15 g orally

Referrals

• Discuss with senior member of the team
• Contact critical care outreach team
• Referral to renal team if K⁺ > 6.5 mmol/L despite medical management. Patient may require dialysis
• Consider referral to Intensive Care Unit (ICU) if:
  • Failure to respond to medical management
  • Patient requires cardiac monitoring
  • Patient requires blood pressure support
  • Deterioration of blood gas following medical management

Future management

• Ensure patients regular prescription is reviewed