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Electrolyte Abnormalities

Electrolyte Abnormalities. Dan Quan, DO Department of Emergency Medicine Maricopa Medical Center Phoenix, Arizona. Electrolyte Abnormalities That May Cause Life Threatening Conditions. Potassium Disorders Magnesium Disorders Sodium Disorders. Potassium.

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Electrolyte Abnormalities

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  1. Electrolyte Abnormalities Dan Quan, DO Department of Emergency Medicine Maricopa Medical Center Phoenix, Arizona

  2. Electrolyte Abnormalities That May Cause Life Threatening Conditions • Potassium Disorders • Magnesium Disorders • Sodium Disorders

  3. Potassium • Most potassium regulation is done by the kidney (95%) • Most abundant intracellular cation

  4. Hyperkalemia • Effects • Depolarizes the cell membrane • Slow ventricular conduction • Decreases action potential duration

  5. Hyperkalemia Electrocardiogram • Normal sinus rhythm • Peaked T waves • Wide QRS • Loss of P waves • Sine wave, ventricular fibrillation, asystole • RBBB, LBBB, heart blocks Lack of EKG changes in the setting of hyperkalemia does not mean treatment should not be initiated

  6. HyperkalemiaPeaked T waves

  7. Hyperkalemia Wide QRS

  8. Hyperkalemia Loss of P Waves

  9. HyperkalemiaBAD

  10. Hyperkalemia Immediate Treatment = IV Calcium • Peripheral IV: 1 ampule calcium gluconate (93 mg) • Central lines: 1 ampule calcium chloride (360 mg) • Stabilizes the excited myocardium by decreasing the resting membrane potential • Onset of action < 3 minutes, Duration of action 30-60 minutes, may repeat in 5 minutes if no effect seen • Infuse IV over 10 minutes • May be given empirically in most cases

  11. HyperkalemiaPushin’ It Back (Into the cell) • IV glucose and insulin • Glucose is given to prevent hypoglycemia • 1 amp (25 g) dextrose 50% (D50) • Regular insulin 10 units IV push • Onset is 20 minutes, Duration of action 30-60 minutes • Albuterol nebulizer treatment • 20 mg over 10 min (decreases K+ by 1 mEq/L) • Onset is 30 minutes, Duration of action 2 hours • Albuterol MDI delivers 90 mcg per spray

  12. HyperkalemiaHey, What About Sodium Bicarb? • Sodium bicarbonate in bolus doses does not decrease potassium in dialysis patients • Does not shift potassium back into the cell • Only after a 4 hour infusion did it decrease potassium by 0.6 mEq/L • May still be useful in those with a metabolic acidosis

  13. HyperkalemiaGettin’ It Out • Furosemide 40–80 mg IV • Onset of action 15 minutes, Duration of action 2–3 hours • Sodium polystyrene sulfonate (Kayexalate) 15–30 g • Onset 2 hours, Duration of action 4–6 hours • No good evidence this does much • Hemodialysis • Onset immediate once it is initiated, Duration of action 3 hours • Removes about 1.5 mEq/L/hour

  14. Hyperkalemia • Cardiac monitor or Serial EKGs for cardiac abnormalities • Lab draw after 1 to 2 hours after therapy initiated to assess treatment progress • May require further intervention

  15. Hypokalemia • Most common causes of hypoK+ are: • GI losses • Diuretic use • Hypomagnesemia • Life threatening emergencies associated with hypoK+ • Diaphragmatic weakness, rhabdomyolysis, and cardiac dysrhythmias (highest risk is a rapid drop to 2.5 mEq/L)

  16. HypokalemiaEKG Findings

  17. Does Hypomagnesemia Contribute? • Magnesium is a “channel closer” in kidney cells • Acts on the Na+/K+ ATPase as a cofactor • Low magnesium “opens” the channel causing potassium loss through urinary excretion • Replacing potassium without replacing magnesium may be futile (refractory hypokalemia)

  18. Potassium Oral Dosing • In general: 10 mEq KCl raises plasma K+ 0.1 mEq/L • Readily absorbed by the GI tract • Immediate release preparations liquid KCl • No evidence for > 50 mEq in a single dose • Do not use extended release KCl (K-Dur) if immediate results are required • Avoid giving > 20 mEq in a single dose (administer every 2 hours) • Increases risk of GI bleeding

  19. Potassium Intravenous Dosing • Infuse potassium chloride at no more than 10 to 20 mEq/hour • Higher rates should be given through a central line • Rates > 80 mEq/hour are associated with dysrhythmias

  20. Magnesium • Where is magnesium located in the body? • 53% bone • 27% muscle • 19% soft tissue • 0.5% RBCs • 0.3% serum • The only way we can assess magnesium levels • Kidney is involved in regulation

  21. Hypomagnesemia • Cardiovascular • Seen as prolonged PR and QT intervals on EKG • Also can cause SVT, PAC, PVC, atrial abnormalities including atrial fibrillation, junctional rhythms, ventricular tachycardia and fibrillation, torsades de pointes

  22. Hypomagnesemia • Consider treatment in these patients • Alcoholics • Asthmatics • Stroke patients • Cardiac patients • Dysrhymias, MI, CHF with dysrhymias • Pregnant patients (preeclampsia) • Hypocalcemia or Hypokalemia • Neurologic problems – vertigo, ataxia, tremor fasciculation, seizures

  23. HypomagnesemiaReplacement • Magnesium sulfate • 1 g is equivalent to 8 mEq of elemental Mg2+ • Maximum infusion rate is 7 minutes/gram • Faster infusion rates cause ventricular dysrhythmias • Oral replacement: Do not exceed 40 mEq of elemental Mg2+ (diarrhea) • Magnesium oxide • 400 mg is equivalent to 20 mEq of elemental Mg2+ • Severe hypomagnesmia replace 48 mEq over 24 hrs

  24. HypomagnesemiaSpecific Recommendations • Seizures or an acute dysrhythmia • 8 to 16 mEq Mg2+ (MgSO4 1-2 g) IV over 5 to 10 minutes • Torsades de pointes • Advanced Cardiac Life Support Guidelines • Loading dose of 16 mEq Mg2+ (MgSO4 2 g) IV over 15 minutes • Then 8 mEq/hour (MgSO4 2 g/hour) • Preeclampsia • 32 mEq (MgSO4 4 g) then 8 mEq/hour (MgSO4 2 g/hour)

  25. Hypermagnesemia • Occurs in renal impaired patients or iatragenic administration • 3 to 4 mEq/L • Hypotension, flushing, nausea, mental status change, hyporeflexia • 5 to 6 mEq/L • QRS widening, QT and PR prolongation, conduction abnormalities • 8 to 10 mEq/L • Severe muscle weakness, respiratory depression, cardiac arrest

  26. Hypermagnesemia Treatment • Calcium 100 to 200 mg over 5-10 minutes IV • e.g. 1 amp calcium gluconate minimum • May require bolus dosing or continuous infusion (2–4 mg/kg/hr)

  27. Hyponatremia • Many causes of hyponatremia • [Na+] < 125 mEq/L are associated with neurologic problems • Cerebral edema • Increased intracranial pressure (encephalopathy) • Seizures

  28. Hyponatremia Management • Rapid correction is dangerous • Acute hyponatremia • More symptomatic • Can tolerate rapid correction • Corrected 1 to 2 mEq/L/hour • Chronic hyponatremia • Correct at 0.5 mEq/L/hour • Risk of central pontine myelinolysis

  29. Central Pontine Myelinolysis • Demyelinating process of the pons • Appears 1 to 6 days after treatment and beyond • May be irreversible • Causes locked-in syndrome • Complete paralysis except for eye control • Mind functions normally

  30. Emergent Treatment of Hyponatremia3% (Hypertonic) Saline • Treatment for any hyponatremia induced neurologic process • 100 mL bolus • Repeat in 30 minutes if no improvement • Raises [Na+] by 2 to 4 mEq/L • Avoid hypertonic saline drips

  31. Hyperkalemia TreatmentSummary

  32. Hypokalemia Treatment Summary • KCl 10 mEq raises K+ by 1 mEq/L • Avoid slow release oral potassium when immediate absorption is required • Limit to 20 mEq per dose every 2 hours • No IV bolus K+ infusions! • Replace magnesium with potassium even when magnesium is normal

  33. Hypomagnesemia Treatment Summary • Serum levels may not reflect total magnesium body stores and deficiency • For seizures, Torsades de Pointes • 8 to 16 mEq Mg2+ (MgSO4 1-2 g) IV • Preeclampsia and eclampsia • 32 mEq Mg2+ (MgSO4 4 g) IV

  34. http://lalainern.tumblr.com/post/23640268629/nurse-with-a-smile-hypermagnesemia-riskhttp://lalainern.tumblr.com/post/23640268629/nurse-with-a-smile-hypermagnesemia-risk

  35. Hyponatremia Treatment Summary • Treat hyponatremia with severe neurologic symptoms with hypertonic saline (3%) • 100 mL IV over 10 minutes • Avoid rapid correction • Central pontine myelinolysis

  36. References • Riccardi A, Tasso F, Corti L, Panariello M, Lerza R. The emergency physician and the prompt management of severe hyperkalemia. Intern Emerg Med. 2012 Jul 29. • Weisberg LS. Management of severe hyperkalemia. Crit Care Med. 2008 Dec;36(12):3246-51. • Huang CL, Kuo E. Mechanism of hypokalemia in magnesium deficiency. J Am Soc Nephrol. 2007 Oct;18(10):2649-52. • Mount DB, Zandi-Nejad K. Disorders of Potassium Balance. Brenner and Rector's The Kidney 9th ed. • Tong GM, Rude RK. Magnesium deficiency in critical illness. J Intensive Care Med. 2005 Jan-Feb;20(1):3-17. • http://www.globalrph.com/magnesium_supplements.htm accessed 8/28/12 • Rosen’s Emergency Medicine • Francis GS. Cardiac complications in the intensive care unit. Clin Chest Med. 1999 Jun;20(2):269-85. • Taal: Brenner and Rector's The Kidney, 9th ed.

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