Hyperkalemia is an electrolyte disorder, which if left unrecognized and untreated, can lead to death. However, by being knowledgeable about potassium, where it is located, what functions it plays, and how it is regulated, the critical care nurse can identify at-risk patients and employ early, often life-saving, interventions. Care of the hyperkalemic patient provides the critical care nurse with a challenging opportunity to use knowledge, skills, and critical thinking in the search for etiologies, the assessment of the patient's clinical picture, and the evaluation of emergency treatments