Management of Hyperkalemia with ECG Changes
For hyperkalemia with ECG changes, immediate treatment should begin with intravenous calcium gluconate to stabilize cardiac membranes, followed by insulin/glucose administration to shift potassium into cells, and then measures to remove potassium from the body. 1
Assessment of Severity
- ECG changes in hyperkalemia progress in a predictable sequence as potassium levels rise: peaked T waves → flattened/absent P waves → prolonged PR interval → widened QRS complex → sine-wave pattern → asystole 1, 2
- Severe hyperkalemia (>6.5 mEq/L) with ECG changes is a medical emergency requiring immediate intervention 1, 3
- Always verify hyperkalemia with a second sample when possible to rule out pseudohyperkalemia from hemolysis during phlebotomy 4, 1
Treatment Algorithm
Step 1: Cardiac Membrane Stabilization (IMMEDIATE)
- Administer intravenous calcium gluconate (10%): 15-30 mL IV over 2-5 minutes OR calcium chloride (10%): 5-10 mL IV over 2-5 minutes 1, 5
- Calcium acts within 1-3 minutes to antagonize the effect of potassium on excitable cell membranes 4, 1
- If no effect is observed within 5-10 minutes, another dose of calcium gluconate may be given 4
- Important: Calcium does NOT lower serum potassium but protects the heart while other treatments take effect 1, 6
- Monitor ECG during calcium administration 5
Step 2: Shift Potassium into Cells (15-30 minutes)
- Administer insulin/glucose: 10 units regular insulin with 25g (50 mL of D50) glucose IV over 15-30 minutes 1, 7
- Consider nebulized albuterol: 10-20 mg nebulized over 15 minutes (can be used alone or to augment the effect of insulin) 1, 6
- Consider sodium bicarbonate: 50 mEq IV over 5 minutes (especially if metabolic acidosis is present) 1, 7
Step 3: Remove Potassium from Body (Hours)
- Administer loop diuretics: furosemide 40-80 mg IV if renal function is adequate 1, 7
- Consider sodium polystyrene sulfonate (Kayexalate): 15-50 g with sorbitol orally or rectally 4, 1
- Initiate hemodialysis for severe cases, especially with renal failure or cases refractory to medical treatment 1, 3, 8
Special Considerations
- For pediatric patients, insulin dosing is 0.1 U/kg IV with glucose (25% dextrose 2 mL/kg) 4
- Calcium gluconate for pediatric patients: 100-200 mg/kg/dose via slow infusion with ECG monitoring 4
- Avoid administering calcium through the same line as sodium bicarbonate or with fluids containing phosphate 5
- Use caution when administering calcium to patients on cardiac glycosides (digoxin) due to increased risk of arrhythmias 5
Monitoring During Treatment
- Continuous cardiac monitoring is essential during treatment 1, 2
- Measure serum calcium every 4 to 6 hours during intermittent calcium infusions and every 1 to 4 hours during continuous infusion 5
- Recheck potassium levels frequently (every 2-4 hours initially) to assess treatment efficacy and monitor for recurrence 8
- For patients with renal impairment, initiate calcium at the lowest recommended dose and monitor serum calcium levels every 4 hours 5
Common Pitfalls and Caveats
- The effect of calcium is temporary (30-60 minutes), so additional measures to lower potassium must follow promptly 1
- Hyperkalemia with nonspecific symptoms may be missed; ECG findings can be variable and not as sensitive as laboratory tests 4
- Calcium should not be administered through the same line as sodium bicarbonate or ceftriaxone 5
- Aluminum toxicity can occur with prolonged administration of calcium gluconate in patients with renal impairment 5
By following this systematic approach to managing hyperkalemia with ECG changes, clinicians can effectively stabilize cardiac membranes, shift potassium into cells, and ultimately remove excess potassium from the body to prevent potentially fatal cardiac arrhythmias.