Community Eye Health. 2013; 26(84): 76. Dianne Pickering Sue Stevens This article will explain how to measure and record blood pressure using a sphygmomanometer (Figure 1). There are many other types of machines for recording blood pressure, such as electronic devices, but these may not be readily available. They can also be difficult to maintain and therefore may give inaccurate readings. What is blood pressure?Blood pressure is the force of blood against the walls of the arteries. Blood pressure is recorded as two numbers, the systolic pressure (the pressure when the heart beats) over the diastolic pressure (the pressure when the heart relaxes between beats). We record this with the systolic pressure first (on the top) and the diastolic pressure second (below). For example, if the systolic pressure is 120 mmHg (millimetres of mercury) and the diastolic pressure is 80 mmHg, we would describe the blood pressure as ‘120 over 80’, written 120/80. All patients must be assessed for fitness before they undergo surgery. As part of this assessment, it important to measure and record the patient's blood pressure. There are two reasons for this:
When measuring a patient's blood pressure, the nurse should be aware of factors that can affect the reading and possibly give a false reading, which could lead to unnecessary medical investigations. These factors include:
Figure 1. Sphygmomanometer (wall-mounted) Figure 2. The arm is supported on a level surface. The cuff is around the upper arm and the stethoscope is over the brachial artery, in the bend of the elbow Blood pressure may vary according to whether the patient is lying down, sitting or standing. It is normally recorded with the patient sitting. You will need
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Contributor InformationDianne Pickering, Nurse Advisor (retired), Community Eye Health Journalmoc.liamtoh@nagol_ennaid. Sue Stevens, Nurse Advisor (retired), Community Eye Health Journal. Articles from Community Eye Health are provided here courtesy of International Centre for Eye Health How do you deflate a blood pressure cuff?Turn the knob on the pump toward you (counterclockwise) to let the air out slowly. Let the pressure fall 2 millimeters, or lines on the dial, per second while listening for your heart sounds.
When deflating the cuff during a blood pressure skill what signals the systolic pressure?When deflating the cuff, the first Korotkoff sound is systolic and the point in which the Korotkoff sounds are no longer heard is diastolic (Hypertension Canada, 2020).
How do you record systolic and diastolic blood pressure?We record this with the systolic pressure first (on the top) and the diastolic pressure second (below). For example, if the systolic pressure is 120 mmHg (millimetres of mercury) and the diastolic pressure is 80 mmHg, we would describe the blood pressure as '120 over 80', written 120/80.
What should be the deflate rate of the cuff in order to prevent an erroneous reading?The cuff should be deflated at a rate of 2-3 mmHg per second. You should note when the sounds first appear with two consecutive beats; this is the systolic pressure.
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