BP is the force or pressure that blood exerts upon the vessel walls. The pulsatile ejection of blood from the left ventricle allows blood to flow from a high pressure area to lower pressure parts of the body. Blood pressure reflects the arterial pressure in the systemic circulation. It varies with each heart beat between a maximum value during systole and a minimal value in diastole. The difference between Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP) is called the pulse pressure. The most significant pressure is the Mean Arterial Pressure (MAP). MAP is calculated using the following equation: MAP=DBP (SBP-DBP divided by 3). This is shown on most automated BP machines and reflects the pressure at which blood flows through the body and at which organs are perfused.
British & Irish Hypertension Society: With Automatic Blood Pressure Monitors [PDF]
British & Irish Hypertension Society: With Manual Blood Pressure Monitors [PDF]
There are a variety of monitors available for clinical use. What type do you use? Best guidance is available from these links below. All kite mark monitors undergo a testing process when they first are on the market and they are graded by a UK or European protocol rating, as the links describe. Make sure any new monitors you get are fit for purpose by following these links. Older monitors are usually the earlier types of those mentioned in the links, and should be satisfactory if they are similar to the ones listed in the links.
British & Irish Hypertension Society: BP Monitors
Pulse point
Please refer to your own local NHS/health board policy for hypertension guidelines.
The following web resources provide the range of underpinning evidence used within these figures.
Reflect on your local practice in relation to current national guidance.
Page last reviewed: 21 May 2020
