A nurse is providing preoperative teaching about patient-controlled analgesia (PCA) to a client. Which of the following statements should the nurse include in the teaching?

A. "You should push the button before physical activity to allow maximum pain control.": Preemptively using the PCA before activities such as ambulation or physical therapy helps prevent breakthrough pain, allowing the client to perform activities more comfortably. This approach maximizes the effectiveness of pain control. B. "Continuous PCA infusion is designed to allow fluctuating plasma medication levels.": Continuous PCA is designed to maintain consistent plasma levels of medication, not fluctuating levels. This ensures steady pain control rather than peaks and troughs. C. "You can adjust the amount of pain medication you receive by pushing on the keypad.": Clients cannot override the preset dosage limits on a PCA pump. The device is programmed by the healthcare provider to deliver safe doses, so self-adjusting the amount is not permitted. D. "The PCA will deliver a double dose of medication when you push the button twice.": PCA pumps have lockout intervals to prevent overdosing. Pressing the button multiple times during the lockout period will not deliver extra doses, so this statement is incorrect and could be dangerous if misunderstood.