How do you manage a patient with hyperkalemia and a peaked T-wave on electrocardiogram (ECG)?

Management of Hyperkalemia with Peaked T-waves on ECG

Calcium gluconate (D) should be administered immediately as first-line treatment for a patient presenting with peaked T-waves on ECG and high potassium levels to stabilize cardiac membranes and prevent life-threatening arrhythmias. 1, 2

Immediate Management Algorithm

1. Stabilize cardiac membranes:

   • Administer 10% calcium gluconate, 15-30 mL IV over 2-3 minutes 2
   • Onset of action: 1-3 minutes; Duration: 30-60 minutes
   • Calcium directly antagonizes the cardiac membrane effects of hyperkalemia without affecting serum potassium levels

2. Shift potassium intracellularly (after calcium administration):

   • Regular insulin 10 units IV with 50 mL of 25% dextrose 2
   • Inhaled beta-agonists (salbutamol/albuterol) 10-20 mg nebulized over 15 minutes 2
   • Consider sodium bicarbonate 50 mEq IV over 5 minutes, especially if metabolic acidosis is present 2

3. Remove potassium from the body:

   • Loop diuretics if renal function is adequate
   • Consider potassium binders for ongoing management
   • Hemodialysis for severe, refractory cases or renal failure 2

Evidence-Based Rationale

The 2020 American Heart Association guidelines clearly state that "For cardiac arrest with known or suspected hyperkalemia, in addition to standard ACLS care, IV calcium should be administered" with a Class 1, Level C-LD recommendation 1. This is the strongest recommendation for hyperkalemia management in the cardiac emergency setting.

Calcium gluconate is the preferred initial treatment because it:

• Stabilizes cardiac membranes within minutes (1-3 minutes) 2
• Counteracts the cardiac toxicity of hyperkalemia
• Prevents progression to more severe arrhythmias
• Does not actually lower serum potassium levels but protects the heart while other treatments take effect 3

ECG Progression in Hyperkalemia

Potassium Level	ECG Changes
5.5-6.5 mmol/L	Peaked/tented T waves (early sign)
6.5-7.5 mmol/L	Prolonged PR interval, flattened P waves
7.0-8.0 mmol/L	Widened QRS, deep S waves
>10 mmol/L	Sinusoidal pattern, VF, asystole, or PEA

The presence of peaked T-waves indicates moderate hyperkalemia that requires urgent treatment to prevent progression to life-threatening arrhythmias 2, 4.

Why Other Options Are Not First-Line:

• Insulin (A): While effective for shifting potassium intracellularly, it should be administered after calcium gluconate has stabilized cardiac membranes 2, 5
• Salbutamol/albuterol inhaler (B): Useful adjunct therapy but has a slower onset (15-30 minutes) and is less reliable than calcium for immediate cardiac protection 2
• Glucagon (C): Not a standard treatment for hyperkalemia management 2, 5

Important Clinical Considerations

• Monitor ECG continuously during treatment
• Calcium administration should be slowed or stopped if bradycardia develops
• Use caution with calcium in patients on digoxin (increased risk of digitalis toxicity)
• Recheck potassium levels 1-2 hours after initial treatment
• Investigate and treat the underlying cause of hyperkalemia (renal failure, medications, acidosis)
• For severe hyperkalemia (>6.5 mmol/L) with significant ECG changes, consider nephrology consultation for possible dialysis 2, 6

A 2022 study showed that calcium gluconate was particularly effective for treating main rhythm disorders due to hyperkalemia (p<0.004), further supporting its use as first-line therapy 3.