What actions should a nurse take when measuring a patient's blood pressure?

Supporting the patient’s arm at heart level is a crucial action when measuring blood pressure because it helps ensure an accurate reading. When the arm is elevated to heart level, the pressure reading reflects the true pressure in the arterial system without the influence of hydrostatic effects that can occur if the arm is too high or too low. This positioning minimizes potential errors, allowing for a more reliable assessment of the patient's blood pressure.

Other options would compromise the accuracy of the readings for various reasons. Measuring blood pressure solely based on one reading can lead to inaccuracies as individual readings may be affected by various transient factors. Likewise, measuring blood pressure immediately following exercise can yield falsely elevated results due to the body's temporary physiological changes. Lastly, checking the blood pressure reading only once during a visit would not provide a comprehensive view of the patient's condition, as blood pressure can vary over time.