06.07 Endo/Metabolic

06.07 Electrolytes imbalances [PDF link]: Potassium: Hyperkalaemia & hypokalaemia. Calcium: Hypercalcaemia & hypocalcaemia. Magnesium: Hypomagnesaemia

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Practical management of hyperkalaemia

• Refer to your Trust guideline for this – there will be one… or there should be really

• If severe hyperkalaemia (K ≥ 6.5)

  • Repeat bloods – do VBG (for K, bicarb and glucose levels) + formal U&Es

    • Might be worth doing it also in a Li-Hep bottle (green top) if there is a possibility this is due to artefactually raised K (esp if there is a big gap between the potassium in yellow top and VBG)

    • If remains raised, escalate to senior

  • Ask for an ECG while you’re processing the bloods

  • Pause drugs contributing to hyperkalaemia or potentially causing renal dysfunction

    • ACEIs, ARBs, aldosterone antagonists (eg spironolactone), K-sparing diuretics (eg amiloride, triamterene)

    • NSAIDs, trimethoprim, co-trimoxazole

    • Consider possibility of digoxin poisoning, ?pause β-blockers

  • ECG – if major abnormalities (see above – includes peaked T waves, QRS widening, etc), give calcium

    • Consider cardiac monitor if K ≥6

  • CALCIUM

    • If not in cardiac arrest, calcium gluconate 10% – 30 mL given in slow IV injection over 10 minutes (≈ 6.8mmol of Ca). Repeat ECG in 5-10 min, consider second dose if no ECG changes

    • If in cardiac arrest, MET CALL + CPR, then calcium chloride 10% – 10 mL rapid bolus + repeat in 5-10 min if no improvement in ECG changes

  • INSULIN/DEXTROSE

    • Check blood glucose first (will be on VBG), and frequently over the next 5-6h

    • IV soluble insulin (Actrapid) – 10U with 25g glucose

      • 25g can be given as 50 mL of 50% IV dextrose (centrally), 125 mL of 20% IV dextrose (central/peripheral), or 250 mL of 10% IV dextrose

    • If pre-treatment CBG <7mmol/L, give further 25 g dextrose as 250 mL of 10% IV dextrose over 5h to prevent hypoglycaemia

    • Single “treatment dose” can reduce K by ~0.9 mmol/L

  • SALBUTAMOL

    • 10 mg via nebuliser (10 mL of 2.5mg/2.5mL)

    • Be aware this can cause or exacerbate tachycardia

    • May be less effective in pts on β-blockers or digoxin

    • Single “treatment dose” can reduce K by ~0.9 mmol/L. If given with insulin/dextrose, cumulative reduction of around 1.2mmol/L

  • OTHERS

    • If volume deplete, give IV crystalloid bolus (eg NaCl) 500-100 mL

    • If volume overloaded, give furosemide

    • If in metabolic acidosis (pH < 7.3, bicarb <20 mmol/L), give 500 mL 1.26% sodium bicarb over 1h – discuss with senior / renal before doing this

    • Potassium binders (eg sodium zirconium cylosilicate) – really more in renal territory, so discuss with them and do as they advise

• If moderate hyperkalaemia (K 6-6.4 mmol/L)

  • Do VBG + ask for ECG, check for changes as above

  • Consider insulin/dextrose or nebulised salbutamol if there is clinical suspicion that potassium may rise or remain at same level

  • Review causes of hyperkalaemia in drugs and diet

  • Daily U&Es until normal