What are the steps for inpatient management of hyperkalemia?

Inpatient Management of Hyperkalemia

The management of hyperkalemia in the inpatient setting requires a stepwise approach based on severity, with immediate treatment using IV calcium for cardiac membrane stabilization, followed by insulin/glucose and beta-agonists for intracellular potassium shifting, and finally potassium elimination strategies. 1

Assessment and Classification

Hyperkalemia is generally defined as serum potassium (K+) >5.5 mEq/L, though classification varies:

• Mild: 5.5-6.0 mEq/L
• Moderate: 6.0-6.5 mEq/L
• Severe: >6.5 mEq/L

Initial evaluation should include:

• ECG monitoring (look for peaked T waves, prolonged QRS, flattened P waves)
• Assessment of symptoms (muscle weakness, paresthesias, cardiac arrhythmias)
• Determination of acute vs chronic hyperkalemia
• Identification of precipitating factors (medications, renal failure, acidosis)

Acute Management Algorithm

Step 1: Cardiac Membrane Stabilization (for severe hyperkalemia or ECG changes)

• IV calcium gluconate 10% (10 mL) - acts within 1-3 minutes
• Effect lasts 30-60 minutes; may repeat dose if no effect seen within 5-10 minutes
• Does not lower serum K+ but protects against arrhythmias 1

Step 2: Intracellular Shifting of K+ (30-60 minute onset)

• IV insulin (10 units) with glucose (50 mL of 50% dextrose) to prevent hypoglycemia
• Nebulized beta-agonists (salbutamol/albuterol 20 mg in 4 mL)
• Consider IV sodium bicarbonate only if metabolic acidosis is present 1
• Note: These measures provide temporary effect (2-4 hours) and do not reduce total body K+

Step 3: Total Body K+ Elimination

• Loop diuretics (IV furosemide) in non-oliguric patients
• Potassium binders:
  • Sodium polystyrene sulfonate (SPS)
  • Newer agents: patiromer or sodium zirconium cyclosilicate (SZC)
• Hemodialysis for resistant hyperkalemia or patients with oliguria/ESRD 1

Additional Important Measures

1. Identify and address underlying causes:

   • Review and hold medications that impair K+ excretion (ACEi, ARBs, MRAs, NSAIDs, trimethoprim, heparin)
   • Correct metabolic acidosis if present
   • Treat hyperglycemia

2. Monitor potassium levels:

   • Recheck K+ within 2-4 hours after acute interventions
   • Monitor for rebound hyperkalemia, particularly after insulin/glucose or beta-agonists

3. Medication management:

   • If RAASi medications (ACEi, ARBs, MRAs) were the cause, consider reintroduction at lower doses after K+ normalization rather than permanent discontinuation 1
   • Use K+ binders to facilitate continued RAASi therapy in patients who need these medications

Common Pitfalls to Avoid

• Delaying treatment in severe hyperkalemia with ECG changes
• Overreliance on temporary measures without addressing total body K+ elimination
• Failure to monitor for rebound hyperkalemia after temporary treatments
• Permanent discontinuation of beneficial RAASi medications instead of using K+ binders to manage hyperkalemia
• Administering insulin without glucose, which can cause dangerous hypoglycemia
• Ignoring pseudohyperkalemia from hemolysis, prolonged tourniquet use, or fist clenching during blood draws 1

Special Considerations

• Patients with chronic kidney disease may tolerate higher K+ levels (up to 5.5 mEq/L) compared to those with normal renal function 1
• The rate of K+ rise is often more important than the absolute value in determining urgency of treatment
• Consider early nephrology consultation for patients with severe hyperkalemia, especially those with kidney failure

By following this systematic approach to hyperkalemia management, clinicians can effectively reduce morbidity and mortality associated with this potentially life-threatening electrolyte disorder.