A nurse is preparing a teaching plan for a client who is starting to receive hemodialysis for chronic kidney disease. Which of the following instructions should the nurse include in the teaching?

Rationale:
A. Prominent P waves: Hyperkalemia typically causes a decrease in P wave amplitude and can eventually lead to their disappearance, rather than making them more prominent. Prominent P waves are not characteristic of elevated potassium levels.

B. Narrowed QRS complexes: Hyperkalemia often leads to a widening, not narrowing, of the QRS complex as potassium levels rise. A narrowed QRS complex is not a hallmark finding in clients with elevated potassium.

C. Shortened PR intervals: Hyperkalemia is more commonly associated with prolonged PR intervals. A shortened PR interval is not typically seen in potassium imbalance and would be more relevant in other conduction abnormalities.

D. Peaked T waves: Tall, peaked T waves are the classic early ECG finding in hyperkalemia. They result from increased potassium altering myocardial repolarization and are often the first electrocardiographic sign of elevated serum potassium.

Rationale:

A. WBC count: Monitoring the white blood cell count is useful for detecting infection, but heroin toxicity primarily affects the respiratory system. An elevated or normal WBC does not provide immediate information about the client's ventilation or gas exchange status.

B. Intake and output: Tracking fluid balance is important for overall patient monitoring, especially in critically ill clients. However, it does not provide direct insight into the effectiveness of mechanical ventilation or the client's oxygenation status.

C. ABGs: Arterial blood gases are the priority assessment because they directly measure the client's oxygenation, ventilation (CO₂ removal), and acid-base status. Since heroin toxicity can cause respiratory depression, ABGs are essential to evaluate the effectiveness of mechanical ventilation.

D. Blood glucose level: Although monitoring glucose is important in critically ill clients, heroin use is not typically associated with hypo- or hyperglycemia. Blood glucose assessment is not as urgent as evaluating respiratory function in this scenario.