AST Surgical Technologist Practice Exam

When a patient's blood pressure reads 135/81, what does 135 refer to?

1. Diastolic

2. Systolic

3. Mean arterial pressure

4. Pulse pressure

The correct answer is: Systolic

The reading of 135 in a blood pressure measurement refers to the systolic blood pressure, which indicates the pressure within the arteries during the contraction of the heart's ventricles. This phase of the cardiac cycle is known as systole, and the systolic pressure is the higher number in a blood pressure reading. Understanding blood pressure involves recognizing that it is expressed as two numbers: the top number is the systolic pressure, and the bottom number is the diastolic pressure. Diastolic pressure reflects the pressure in the arteries when the heart is at rest between beats. Mean arterial pressure is a calculated average that provides an overall assessment of blood flow, and pulse pressure is the difference between the systolic and diastolic pressures. In this case, since 135 is the higher of the two values presented, it accurately corresponds to the systolic measurement.