Common replacement doses for K, Mg, PO4, Ca.
Potassium
- • Oral KCl 40-80 mmol/day in divided doses
- • IV: max 10 mmol/h peripheral, 20 mmol/h central (monitored)
Magnesium
- • MgSO4 2 g IV over 20 min
- • Higher if torsades (2 g bolus, then 1-2 g/h)
Phosphate
- • KPhos / NaPhos 0.16-0.32 mmol/kg over 4-6h
- • Check Ca and renal function
Calcium
- • 10 mL 10% calcium gluconate IV slow for symptomatic hypocalcaemia
- • Treat underlying Mg deficiency
Pearls
- • Always correct Mg before K
- • Recheck within hours of replacement
Educational support only — follow institutional ICU protocols.
