Overview
Overview
Hyperkalemia is a serum potassium concentration above 5.5 mmol/L; some provincial guidance uses above 5.2 mmol/L as its alert threshold.
Hyperkalemia is a serum potassium concentration above 5.5 mmol/L; some provincial guidance uses above 5.2 mmol/L as its alert threshold. A value at or above 5.5 mmol/L warrants urgent assessment, but the ECG, clinical status, rate of rise, and kidney function determine immediate danger. Potassium changes myocardial excitability and conduction, so a patient may have only weakness—or no symptoms—while the rhythm deteriorates. Peaked T waves may progress to PR prolongation, P-wave loss, QRS widening, and a sinusoidal waveform. ECG toxicity is a cardiac emergency: stabilize the myocardial membrane with intravenous calcium, shift potassium into cells, then remove potassium while monitoring rhythm, glucose, renal function, and response.