Hyperkalemia

Suspect in:

  • Renal failure (especially if oliguria or eGFR<15)
  • Acidosis (diabetic ketoacidosis, adrenal insufficiency)
  • Cell death (burns, rhabdomyolysis, trauma, tumor lysis syndrome)
  • Absorption (substantial GI bleed)
  • Drugs (Digoxin, Tacrolimus, Cyclosporine, beta-blockers [BB], ACEI/ARB, NSAID, K+ sparing diuretic)

Symptoms:

  • Muscle weakness or paralysis
  • Palpitations

ECG changes (variable and unpredictable):

  • Peaked T waves, Prolonged PR, Flattening P, Wide QRS, Sine Wave
  • Bradycardia (sinus, wide-complex, slow atrial fibrillation)
  • Ventricular tachycardia (VT) mimic, often sharper T-waves and slower rate than usual VT, eg <120bpm

ACUTE MANAGEMENT OF SEVERE HYPERKALEMIA

If K>6.5 or suspected high, or risk of increasing, or ECG changes or symptomatic/peri-arrest

In cardiac arrest, Calcium Chloride 1g IV slow push, Sodium Bicarbonate 50mEq IV push, shift/eliminate potassium once ROSC achieved

  • Assess ABC
  • Vital signs (incl. CBG capillary blood glucose)
  • Assess hydration status
  • Cardiac monitor
  • Defibrillation/pacing pads
  • IV access (large peripheral vein if possible)
  • ECG

Consider Reversible Causes

  • Pseudohyperkalemia (blood drawing/testing technique, hemolysis, elevated platelets/WBC)
    • Repeat potassium with second sample, if available, relevant, and time permits
  • Rule out Digoxin toxicity
    • Treat with digoxin-specific antibody fragments (Digibind) if available
  • Acidosis (diabetic ketoacidosis, adrenal insufficiency)
  • STOP potassium supplementation
  • Re-assess medication (BB, digoxin, ACEI/ARB, NSAID, K+ sparing diuretic)

1. STABILIZE (Onset <5 minutes, duration 30 minutes)

  • Calcium Gluconate 100 mg/mL (10%) 3g (30mL) IV over 5-10 mins
    • Repeat every 5 mins PRN if ECG changes persist or recur
    • Ideally use large peripheral or central vein
    • Avoid extravasation which can cause tissue necrosis
    • No evidence of contraindication in digoxin toxicity
    • Do NOT administer sodium bicarbonate simultaneously via same access (risk of formation of insoluble calcium salts) or mix with any other drugs (risk of incompatibility)
  • Alternative: Calcium Chloride 100 mg/mL (10%) 1g (10mL) IV over 5-10 mins
    • Has higher risk of tissue necrosis if extravasation

2. SHIFT (Onset <15mins, decrease 0.5mEq/L)

  • Insulin regular (Humulin R) 10 units IV (not subcutaneous) bolus, with flush after
    • If serum glucose <16mmol/L, give 50g of glucose (100mL of D50W) IV immediately following insulin
    • Check glucose q30 mins x 2 then hourly x 2,
      • If <4mmol/L give 25g of glucose (50mL of D50W) IV
  • Salbutamol (Ventolin), via one of:
    • Unlikely to work if patient on beta-blockers
    • Nebulized 20mg over 10 mins
    • MDI-spacer 12 puffs (1200mcg) puffs inh over 2 mins
    • Intravenous 0.5mg in 100ml of D5W over 20 mins
      • Caution has been advised for use in patients with ischemic heart disease
  • Only if a vasopressor is needed, consider Epinephrine 5-20mcg IV q2-5mins treats both hyperkalemia and bradycardia

3. ASSESS HYDRATION STATUS (Elimination)

  • If hypovolemic:
    • AVOID normal saline as risk of hyperchloremic metabolic acidosis that will worsen hyperkalemia
    • If metabolic acidosis suspected, Sodium Bicarbonate 150mEq (3 amps) in 1L of D5W IV over 4 hours (do NOT administer with calcium via same intravenous access)
    • If no acidosis suspected, Ringers Lactate IV bolus
  • If hypervolemic:
    • Furosemide 80-160mg IV
  • If euvolemic, may consider both:
    • Furosemide 80-160mg IV
    • Ringers Lactate IV bolus to maintain euvolemia
  • Dialysis as indicated

4. PREVENT

  • Renal diet (low potassium <1.5g/d)
  • Re-assess medication (BB, digoxin, ACEI/ARB, NSAID, K+ sparing diuretic)
  • Elimination by gastrointestinal tract, eg. PEG 3350 (Lax-a-day) and Polystyrene sulfonate (Kayexalate) are only indicated in the chronic management of chronic hyperkalemia