SAQ 108 – Cardiology – life-threatening hyperkalaemia ECG

Question 5. life-threatening hyperkalaemia ECG.

a. Diagnosis

• Life-threatening hyperkalaemia.
• Failure to pace or capture may be noted but is not required for the mark.

b. ECG features

• Very broad QRS complexes, greater than 400 msec.
• ST segment blurring.
• Absent P waves.
• Sine-wave appearance.
• Failure to pace or failure to capture.

c. Likely causes

• Acute renal failure.
• Digoxin toxicity.
• Potassium-sparing diuretic with or without ACE inhibitor.
• Accidental or deliberate potassium overdose.
• Rhabdomyolysis.
• Less likely causes include transfusion, haemolysis, hyperthermia, or Addison's disease.

d. Treatments

• Calcium gluconate 10 mL of 10% solution over 10 minutes, unless digoxin toxicity changes the risk-benefit decision.
• Sodium bicarbonate 1 mEq/kg over 30 minutes.
• Dextrose 50% 50 mL plus 5-10 units of short-acting insulin.
• Nebulised salbutamol 5 mg.
• Resonium.
• Dialysis if chronic or severe renal failure.
• Digoxin immune Fab if digoxin toxicity is suspected.