ARRT Patient Care Practice Exam

How is blood pressure typically measured?

1. Beats per minute

2. Degrees Fahrenheit

3. Liters per minute

4. Millimeters of mercury (mmHg)

The correct answer is: Millimeters of mercury (mmHg)

Blood pressure is typically measured in millimeters of mercury (mmHg), which is a standard unit of pressure. This measurement indicates the force exerted by circulating blood against the walls of blood vessels, specifically during two critical phases of the cardiac cycle: systole and diastole. The systolic pressure, which is the higher number, represents the pressure in the arteries when the heart beats and pumps blood. The diastolic pressure, the lower number, reflects the pressure in the arteries when the heart is at rest between beats. Using mmHg for blood pressure measurement dates back to when mercury manometers were commonly used for this purpose. It allows for a consistent and easily understood notation that is universally recognized in healthcare, making it possible for practitioners to communicate effectively regarding a patient’s cardiovascular status. The other options relate to different kinds of measurements and are not applicable to blood pressure. For instance, beats per minute refers to heart rate, degrees Fahrenheit relates to temperature readings, and liters per minute typically measures flow rates, such as in respiratory assessments. These units are used for entirely different physiological parameters and do not pertain to the measurement of blood pressure.