A client with a history of heart failure arrives at the emergency department describing an onset of fatigue and weakness. The client has been taking spironolactone 50 mg tablets PO every day. The nurse receives a report from the lab that the client has a serum potassium level of 6.2 mEq/L (6.2 mmol/L). Which intervention is most important for the nurse to implement?

Choice A rationale Comparing muscle strength bilaterally is important in assessing overall physical health and detecting any potential neuromuscular disorders. However, in the context of a client with a history of heart failure and elevated potassium levels, this would not be the most critical intervention. High potassium levels can lead to hyperkalemia, which can cause serious heart rhythm disturbances. Choice B rationale Observing the color and amount of urine can provide valuable information about the client’s hydration status and kidney function. In the case of heart failure, monitoring urine output can help assess the effectiveness of diuretic therapy and the progression of the disease. However, it is not the most immediate concern given the client’s high potassium levels. Choice C rationale Determining the apical pulse rate and rhythm is the most important intervention in this scenario. A serum potassium level of 6.2 mEq/L is higher than the normal range (3.5-5.0 mEq/L) and can cause life-threatening heart rhythm abnormalities. Therefore, the nurse should prioritize assessing the client’s heart rhythm to detect any abnormalities caused by this electrolyte imbalance. Choice D rationale Assessing the strength of deep tendon reflexes can help identify changes in neuromuscular function and is often used in neurological assessments. However, it is not the most critical intervention in the context of elevated potassium levels and heart failure.