A patient with a history of heart failure presents at the emergency department reporting fatigue and weakness. The patient has been taking 50 mg spironolactone tablets orally every day. The nurse receives a lab report indicating the patient’s serum potassium level is 6.2 mEq/L (6.2 mmol/L). What is the most important intervention for the nurse to implement?

Choice A rationale Comparing muscle strength bilaterally is not the most important intervention in this situation. While muscle weakness can be a symptom of hyperkalemia, it is not the most immediate concern. Hyperkalemia can lead to life-threatening cardiac dysrhythmias, which is a more immediate threat to the patient’s life. Choice B rationale Observing the color and amount of urine can provide information about the patient’s renal function, which is important in the regulation of potassium. However, this is not the most immediate concern when a patient’s serum potassium level is dangerously high. Choice C rationale Determining the apical pulse rate and rhythm is the most important intervention. Hyperkalemia can cause cardiac dysrhythmias, so the nurse should immediately assess the patient’s heart rate and rhythm. The nurse should also place the patient on a cardiac monitor, if not already done, and notify the healthcare provider immediately. Choice D rationale Assessing the strength of deep tendon reflexes can provide information about neuromuscular function, which can be affected by hyperkalemia. However, this is not the most immediate concern. The nurse’s priority is to assess and monitor for life-threatening cardiac dysrhythmias.