What is the treatment for hyperkalemia indicated by peaked T waves on an electrocardiogram (EKG)?

Treatment of Hyperkalemia with Peaked T Waves on EKG

Immediately 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) to stabilize the cardiac membrane and prevent life-threatening arrhythmias, followed by therapies to shift potassium intracellularly (insulin/glucose and albuterol) and promote potassium elimination. 1

Understanding the Clinical Significance

Peaked T waves represent the earliest ECG manifestation of hyperkalemia, typically appearing when serum potassium exceeds 5.5 mmol/L. 1 While this is the most commonly recognized finding, the presence of any ECG changes indicates severe cardiotoxicity requiring immediate treatment, as hyperkalemia can rapidly progress through a predictable sequence: peaked T waves → flattened P waves → prolonged PR interval → widened QRS → sine wave pattern → asystolic cardiac arrest. 1

Critical caveat: ECG findings are highly variable and not as sensitive as laboratory testing in predicting hyperkalemia severity—the absence of ECG changes does not rule out dangerous hyperkalemia, particularly in patients with chronic kidney disease, diabetes, or heart failure who may tolerate higher potassium levels without ECG manifestations. 1

Immediate Treatment Algorithm

Step 1: Membrane Stabilization (Acts within 1-3 minutes)

• Calcium gluconate 10%: 15-30 mL IV over 2-5 minutes (preferred in most settings) 1
• OR calcium chloride 10%: 5-10 mL (500-1000 mg) IV over 2-5 minutes (more potent but requires central access) 1
• This rapidly reduces membrane excitability and minimizes arrhythmia risk but does NOT lower serum potassium 2
• If no effect within 5-10 minutes, repeat the dose 2

Step 2: Shift Potassium Intracellularly (Acts within 30 minutes)

Administer multiple agents simultaneously for additive effect:

• Insulin with glucose: 10 units regular insulin with 25g glucose (50 mL of D50) IV over 15-30 minutes 1
• Nebulized albuterol: 10-20 mg over 15 minutes to augment insulin/glucose effects 1
• Sodium bicarbonate: 50 mEq IV over 5 minutes (particularly beneficial if concurrent metabolic acidosis present, though poor efficacy when used alone) 1

These therapies redistribute potassium into cells but do not eliminate it from the body. 2

Step 3: Promote Potassium Elimination

• Furosemide: 40-80 mg IV (if renal function permits) 1
• Hemodialysis for refractory cases or severe renal impairment 2
• Sodium polystyrene sulfonate (Kayexalate): 15-50 g with sorbitol orally or rectally for subacute management 1

Important limitation: Sodium polystyrene sulfonate should NOT be used as emergency treatment for life-threatening hyperkalemia due to delayed onset of action. 3

Monitoring Requirements

• Continuous cardiac monitoring is essential throughout treatment 1, 4
• Recheck serum potassium within 1-2 hours after initial interventions
• Monitor blood glucose closely after insulin administration to prevent hypoglycemia 2

Common Pitfalls to Avoid

1. Pseudohyperkalemia: Consider this when ECG findings don't match laboratory values—can result from repeated fist clenching, poor phlebotomy technique, hemolysis, or slow specimen processing 2

2. Relying solely on ECG: While peaked T waves are classic, they are actually rarely the sole manifestation of life-threatening hyperkalemia 5

3. Delaying calcium administration: Calcium should be given immediately when any ECG changes are present, as it works within 1-3 minutes to prevent cardiac arrest 1

4. Using only one intracellular shift agent: Combining insulin/glucose with albuterol provides additive benefit 1

5. Forgetting to address underlying cause: Review medications (RAASi, potassium-sparing diuretics, NSAIDs), assess renal function, and implement dietary potassium restriction 1

Post-Acute Management

After stabilizing the acute episode:

• Identify and address the underlying cause (renal failure, medications, tissue breakdown) 2
• Consider newer potassium-binding agents for chronic management in patients requiring ongoing RAASi therapy 1
• Implement individualized potassium monitoring based on comorbidities, with assessment 7-10 days after starting or increasing RAASi doses 2