Electrolyte Management and Repletion
Last updated: 31-Jul-2011 10:21 PM 
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Potassium

  • Hyperkalemia management
    • Watch for EKG changes if K > 6.0 mmol/L.  Consider low K+ diets
    • Emergent
      • D50W 1-2 amps IVP + Regular Insulin 10 units IVP - Transiently reduces K+
      • Albuterol, nebulized - Transiently reduces K+
      • Calcium gluconate 10% 10mL (1gm) via central line/large peripheral line (preferred over CaCl2Use only when necessary.  Extravasation may cause tissue necrosis
      • CaCl2, 1gm via central line over 2min
      • Hemodialysis - If conservative treatment fails
    • Routine
      • Kayexalate 15-60mg PO up to 4 times/day 30 gm PR, retain for >60 min - Binds to K+ in food.  No effect if NPO.  Give cleansing enema before and after to avoid tissue necrosis
      • IV fluids
      • Hemodialysis
  • Hypokalemia management - Potassium repletion/replacement
    • Make sure Mg2+ is normalized (> 1.5 mg/dL) before correcting K+.  Do not mix Ca2+ in IVF.
    • Oral
      • KDur tabs 40meq PO q4H x 1-3 doses - increases K+ by ~0.3 mmol.L
      • oral potassium replacement/repletion
    • IV
      • Quick
        • KCl 10meq/100 mL sterile water IV over 1 hr x 1-3 doses (premixed)
          • increases K+ by ~0.1 mmol.L; if mixed with D5W, may transiently decrease [K+]
        • KCl 20meq/50mL SW via central line over 1 hr x 1-3 doses
          • increases K+ by ~0.2 mmol.L
        • K-Phos 3mL/100mL IV over 1 hr x 1-3 doses
          • Use only if phos < 1.0 mg/dL; monitor during administration; increases K+ by ~0.1 mmol.L and phos by 0.2-0.4 mg/dL
      • Detailed
        • Recommended rate of infusion is 10 mEq/h 
        • Maximum rate of intravenous replacement is 20 mEq/h with continuous ECG monitoring (the 
          maximum rate may be increased to 40 mEq/h in emergency situations)
        • Maximum Concentration for Central IV administration = 20 mEq/50 mL
        • Maximum Concentration for Peripheral IV administration = 10 mEq/50 mL
        • potassium replacement/repletion

Magnesium

  • Hypermagnesemia
    • Stop Mg supplementation - If renal function is normal, should correct w/o intervention
    • Hemodialysis - if renal function is significantly impaired
    • Emergent
      • IV calcium gluconate 1gm via central line - may cause necrosis
  • Hypomagnesemia
    • Oral
      • Magnesium oxide 400mg PO - may cause diarrhea (up to 4 days)
    • IV
      • Magnesium sulfate 1gm/100mL NS IV over 1 hour - up to 3 doses - increases Mg ~0.2-0.5 mg/dL
      • iv magenesium replacement/repletion
      • Infusions should be no faster than 1gm of magnesium sulfate every 30 minutes.

Phosphate

  • Hyperphosphatemia
    • Oral
      • Calcium acetate (PhosLo) 667 PO TID with meals - Avoid if on HD
      • Sevelamer (Renagel) - For patients on HD
      • Low phosphate diet
    • Emergent
      • IV fluids
      • Acetazolamide 15mg/kg q3-4 hrs (if acute)
      • Hemodialysis - For symptomatic hypocalcemia and impaired renal failure
    • Note: Phosphate binders reduce the absorbable phosphate in food.  There is no effect if the patient is NPO
  • Hypophosphatemia
    • Oral
      • NeutraPhos 1packet (250mg) PO TID with meals
    • IV
      • Quick
        • Na-Phos 3ml/100ml SW IV over 1hr x 1-3 doses - increases phos ~0.2-0.5 mg/dL
        • K-Phos 3ml/100ml NS/D5W IV over 1hr x 1-3 doses - increases K+ ~0.1 mmol/L, increases phos 0.2-0.5 mg/dL
      • Detailed
        • Recommended rate = 3mmol/hr (= 4.4 mEq/h of K)
        • Maximum rate = 10 mmol/hr (= 15 mEq/h of K)
        • Use SODIUM phosphate for patients with serum potassium > 4.5 mEq/L and serum sodium < 145 mEq/L
        • iv phosphorus replacement/repletion
        • Do not mix with Ca2+ in IVF.  IV phosphate can cause hypocalcemia, induce renal failure, and life-threatening arrythmias.  Patient should be monitored during IV administration

Calcium

  • Hypercalcemia
    • ​IVF (NS) up to 200-300 mL/hr - Watch for CHF
    • Furosemid IV - May give 90mg if Ca2+ > 13.5 mg/dL
    • Pamidronate 60mg IV over 2hrs x 1 - Use only when volume status has been corrected
    • Stop oral calcium intake
  • Hypocalcemia
    • ** Not routinely repleated unless symptomatic **
    • Asymptomatic
      • 1000-1500mg calcium orally in divided doses
    • Symptomatic
      • Calcium gluconate 1gm via central line over 2min - preferred over CaCl2
      • CaCl1gm via central line over 2min - may cause necrosis

Reference

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