Fluids, Electrolytes & Nutrition: Potassium (K)

Causes

• Pseudohyperkalemia – False Elevation Due to Blood Cell Rupture Associated with Blood Draw
• Renal Failure
• Adrenal Insufficiency (Addison’s Disease)
• Medications:
  • ACE Inhibitors
  • Beta Blockers
  • Succinylcholine
  • Excessive Potassium Supplementation
• Crush Injury or Rhabdomyolysis
• Tumor Lysis Syndrome
• Significant GI Bleeding
• Metabolic Acidosis
• Diabetic Ketoacidosis (DKA)

Presentation

• Muscle Weakness or Paralysis
• Cardiac Conduction Abnormalities
• EKG Changes:
  • Initial Findings:
    • Peaked T Waves
    • Shortened QT Interval
  • Later Findings:
    • Lengthening or PR Interval
    • Lengthening of QRS Complex
• *Clinical Manifestations Generally Do Not Occur Until After Level ≥ 7.0 mEq/L

Treatment Options

• IV Calcium
  • Effect: Stabilize Cardiomyocyte Membrane
  • Generally the First Medication Given
• Insulin & Glucose
  • Effect: Insulin Causes an Intracellular Potassium Shift
  • 30-60 Minutes to Cause Effect
  • Intracellular Shift Can Inhibit Clearance by Dialysis & Cause Rebound Hyperkalemia
• Kayexalate
  • Effect: Prevents Potassium Reabsorption in GI Tract
  • Rectal Administration Takes 1-4 Hours to Cause Effect
  • Oral Administration Takes > 6 Hours to Cause Effect
• Furosemide (Lasix)
  • Effect: Increased Potassium Excretion in Urine
• Albuterol
  • Effect: β-Agonist Induces Intracellular Potassium Shift
• Dialysis
  • Causes an Immediate Effect

Treatment Approach

• Emergent Treatment:
  • Indications for Emergent Treatment:
    • EKG Changes
    • Muscle Weakness or Paralysis
    • K > 6.5 mEq/L
    • K > 5.5 mEq/L with Renal Failure & Ongoing Tissue Breakdown or Potassium Absorption
  • Emergent Treatment: IV Calcium & Insulin/Dextrose
    • Also Consider Hemodialysis, Kayexalate or Furosemide
• Prompt Treatment:
  • Indications for Prompt Treatment:
    • K > 5.5 mEq/L & Severe Renal Disease or Need for Surgical Optimization
  • Prompt Treatment: Consider Hemodialysis, Kayexalate or Furosemide
    • Correct Any Underlying Pathologies
• *Avoid Normal Saline
  • NS Induces Hyperchloremic Metabolic Acidosis Which Worsens Hyperkalemia
  • Lactated Ringer is Preferred Despite Potassium Content