When assessing a client with a serum potassium level of 2.5 mEq/L (2.5 mmol/L), which intervention is most important for the nurse to implement?

A. Compare muscle strength bilaterally is not the most immediate concern. Although muscle weakness is a potential sign of hypokalemia, the priority is assessing for cardiac complications, as potassium imbalances can cause life-threatening arrhythmias. B. Determine apical heart rate and rhythm is the most important intervention. A potassium level of 2.5 mEq/L is dangerously low and can lead to life-threatening cardiac arrhythmias. The nurse should assess the heart rate and rhythm to detect any abnormalities such as bradycardia, tachycardia, or irregular rhythms, which are common in hypokalemia. C. Observe color and amount of urine is not the priority. While renal function is important, the immediate concern in this case is the potential for severe cardiac complications due to the low potassium level. D. Assess strength of deep tendon reflexes is important for detecting signs of hypokalemia, but it is secondary to assessing the heart, as potassium imbalances primarily affect cardiac function.