A 68-year-old man with a history of end-stage renal disease is brought to the emergency department due to profound generalized weakness and palpitations. He denies chest pain or shortness of breath. He missed his last two hemodialysis sessions. His blood pressure is 110/70 mm Hg and his heart rate is 54/min. Physical examination reveals a lethargic-appearing man with mild bradycardia. An electrocardiogram is immediately performed and shows peaked T waves and widening of the QRS complex. Laboratory studies are pending.
A) Calcium gluconate
This patient has a clinical scenario of missed hemodialysis sessions and ECG changes (peaked T waves, QRS widening) highly suggestive of hyperkalemia. The immediate priority is to antagonize the effect of potassium on the cardiac conduction system. Intravenous calcium gluconate or chloride stabilizes the resting membrane potential of cardiomyocytes within minutes.
Answer choice B: Hemodialysis, is incorrect. Hemodialysis is the definitive treatment for removing potassium in a patient with end-stage renal disease (ESRD), but the patient must be stabilized from a cardiac standpoint first to ensure they survive long enough to undergo hemodialysis.
Answer choice C: Inhaled albuterol, is incorrect. Albuterol shifts potassium into the intracellular space. It is useful as an adjunctive therapy but is not the first-line treatment for cardiac membrane stabilization.
Answer choice D: Intravenous insulin and glucose, is incorrect. Like albuterol, insulin shifts potassium into cells. While vital for lowering the serum concentration, it does not protect the heart from the immediate effects of hyperkalemia.
Answer choice E: Sodium polystyrene sulfonate, is incorrect. Sodium polystyrene sulfonate is a potassium-binding resin. It takes hours to work and is no longer recommended for acute management due to slow onset and potential risks like intestinal necrosis.
Key Learning Point
The clinical management of hyperkalemia is dictated by the severity of the potassium elevation and the presence of electrocardiogram (ECG) changes. In patients with severe hyperkalemia (typically K+ > 6.5 mEq/L) or any hyperkalemia-associated ECG changes, such as peaked T waves, PR interval prolongation, or QRS widening, the immediate priority is the stabilization of the cardiac myocyte membrane with intravenous calcium (calcium gluconate or calcium chloride). This does not lower the serum potassium level but prevents lethal arrhythmias. Following stabilization, the next objective is to shift potassium into the intracellular compartment using insulin with glucose to prevent hypoglycemia or inhaled beta-2 agonists. Finally, the total body potassium burden must be reduced through removal therapies, which include the use of cation-exchange resins, loop diuretics (if renal function is preserved), or emergent hemodialysis in patients with refractory elevation or severe renal failure.
