Final answer:
The nurse's priority assessment action when noting elevated serum potassium levels in a patient with acute kidney failure is to monitor the patient's cardiac status, as hyperkalemia can lead to dangerous arrhythmias.
Step-by-step explanation:
When a nurse notes an elevated serum potassium level for a client in acute kidney failure, the priority assessment action is to monitor the patient's cardiac status. Hyperkalemia can significantly affect the heart by causing partial depolarization of the cardiac cells, potentially leading to dangerous arrhythmias and cardiac arrest. Given potassium's vital role in muscle function, including the heart muscle, it's crucial that the nurse assesses for any signs of cardiac distress and is prepared to act immediately to reduce potassium levels if necessary.
This can include interventions such as glucose and insulin administration, which can help drive potassium back into the cells and temporarily reduce its serum level, or administering sodium polystyrene sulfonate, which binds potassium in the gut and can help remove it from the body.