On Call: Electrolyte Replacement

General Approach

LyteReplacementDoseWill RaiseNotes
KKCl10 mEq0.05-0.1 mEq/LPreferred Over K-Phos
CaCa-Gluconate1 g0.15 mg/dLIf Mild
 CaCl1 g0.45 mg/dLIf Severe/Symptomatic
MgMg-Sulfate1 g0.2 mg/dLIV Preferred
PhosNa-Phos15 mmol0.4 mg/dLPreferred Over K-Phos
 K-Phos15 mmol0.4 mg/dLAlso Gives 22 mEq K

Goal of Replacement

  • Goal: Normal Serum Electrolyte Levels
  • Generally Attempt to Achieve Middle of the Normal Range, Not Lower Limit, to Allow for Ongoing Losses (Ex: K Goal 4.0, Not 3.5)

Route

  • Enteral (PO) Replacement:
    • Generally Preferred if Able to Tolerate Oral Intake (Not Magnesium)
    • Slower Correction
  • Intravenous (IV) Replacement:
    • Preferred Route if Deficiency Severe
    • More Rapid Correction

Replacement

Potassium

Calcium

  • *See Fluids, Electrolytes & Nutrition: Calcium (Ca)
  • Calcium Gluconate
    • IV Correction: 1 g will Increase Ionized Ca 0.15 mg/dL
    • Preferred for Mild Asymptomatic Deficiencies
  • Calcium Chloride (CaCl2)
    • IV Correction: 1 g will Increase Ionized Ca 0.45 mg/dL
      • Provides Three Times the Amount of Elemental Calcium per Gram as Calcium Gluconate
    • Preferred for Severe or Symptomatic Deficiencies
    • Corrosive to Veins & Requires a Central Line

Magnesium

Phosphate

  • *See Fluids, Electrolytes & Nutrition: Phosphate (PO4)
  • Sodium Phosphate (Na Phos)
    • IV Correction: 15 mmol with Increase Serum PO4 0.4 mg/dL
    • Preferred Choice Over K Phos
    • Rechecking: Wait 2-4 Hours
    • Enteral Dosing:
      • Variable Bioavailability – Dose Should Be Tripled
      • 250 mg PO is Equivalent to 8 mmol
      • Generally Given in 3-4 Doses Over the Day
  • Potassium Phosphate (K Phos)
    • Same Correction as Na Phos
    • Also Provides 22 mEq K per 15 mmol

Normal Requirements

Requirements Per Day Mn

  • Potassium (K): 0.5-1 mEq/Kg/Day
  • Sodium (Na): 1-2 mEq/kg/Day
  • Chloride (Cl): 2-3 mEq/Kg/Day

Normal Levels

  • Sodium (Na): 135-145 mEq/L
  • Chloride (Cl): 96-106 mmol/L
  • Potassium (K): 3.5-4.5 mEq/L
  • Calcium (Ca): 9.0-11.0 mg/dL
    • Ionized Calcium: 4.5-5.5 mg/dL
  • Phosphate (PO4): 3.0-4.5 mg/dL
  • Magnesium (Mg): 1.5-2.5 mEq/L
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Mnemonics

Daily Chemical Requirements

  • K-Na-Cl: 1-2-3