Overview
Introduction
A potassium result can become a cardiac emergency before the patient looks critically ill.
A potassium result can become a cardiac emergency before the patient looks critically ill. Consider a patient with kidney failure who reports new hand tingling while the monitor shows tall, narrow T waves: the priority is not to wait for the next routine blood draw. Hyperkalemia is generally defined as a serum potassium above 5.5 mmol/L; some provincial guidance uses above 5.2 mmol/L. A value of 5.5 mmol/L or higher warrants urgent assessment. The clinical sequence is purposeful: recognize electrical toxicity, call for immediate support, stabilize the cardiac membrane, shift potassium into cells, and then remove potassium from the body. Reassess the rhythm, potassium trajectory, glucose, urine output, and hemodynamic response after each step.