EM · Electrolyte emergencies — potassium and sodium

Electrolyte emergencies — potassium and sodium

Also known as Hyperkalaemia · Hyponatraemia · Osmotic demyelination syndrome · Hypokalaemia · Hypernatraemia · Diabetes insipidus

Electrolyte emergencies — potassium and sodium. Hyperkalaemia (a serum potassium over 6.5 mmol/L, or any level with ECG change) is a time-critical arrhythmia risk treated up an antidote ladder of membrane stabilisation (calcium chloride 10 mL of 10 per cent IV), potassium shift (insulin 10 units with 50 mL of 50 per cent dextrose IV, salbutamol 10 to 20 mg nebulised, sodium bicarbonate IV reserved for metabolic acidosis) and potassium removal (patiromer, sodium zirconium, dialysis). Hypokalaemia (potassium under 3.5 mmol/L) shows U waves and a prolonged QU interval, precipitates torsades de pointes and potentiates digoxin toxicity, and is replaced intravenously at no faster than 10 mmol per hour peripherally and 20 mmol per hour centrally, with the magnesium corrected first. Hyponatraemia (sodium under 125 mmol/L) splits into acute — cerebral oedema and seizure, treated with 3 per cent hypertonic saline 100 mL IV bolus — and chronic, corrected slowly (under 8 mmol/L in 24 hours to avoid osmotic demyelination). Hypernatraemia (sodium over 145 mmol/L) is always a water-deficit problem, corrected at no faster than 0.5 mmol/L per hour with free water (oral or 5 per cent dextrose) and desmopressin for central diabetes insipidus. The ECG changes of hyperkalaemia (peaked T waves, widened QRS, sine wave, VF arrest), the pseudohyperkalaemia trap, and the corrected sodium for hyperglycaemia. ACEM-primary, globally tagged.