Providing accurate and reliable blood pressure day and night
The Ambulatory Blood Pressure Monitor (ABPM) is considered the gold standard for measuring blood pressure by clinicians worldwide. It provides valuable diagnostic information that in-clinic and home blood pressure monitoring systems are incapable of measuring including:
- BP variability and a more accurate estimation of true blood pressure
- Overnight changes in blood pressure (dipper status)
- Morning surges in blood pressure
In general, ABPM is recognized in the medical community as a valuable tool for supporting the management of appropriate pharmacologic treatment as well as the assessment of1,2:
- “White coat” hypertension, when elevated blood pressure measurements are recorded in the physican’s office environment while blood pressure readings outside the physician’s office are within a normal range.
- Resistant hypertension, when multiple anti-hypertensive medications fail to adequately control high blood pressure.
- Masked hypertension, when in-office measurements fall within an acceptable range, but the mean blood pressure is actually above the acceptable range.
- Hypotensive symptoms with hypertensive medications.
The diagnostic test begins with fitting a patient with a portable monitor and BP cuff. The patient leaves and returns the next day. Over this period of time, the monitor takes measurements periodically as programmed by the clinician, generally each 15-30 minutes during awake hours and 30-45 minutes during sleeping hours. When the patient returns, these measurements are transferred to a computer where they can be easily viewed and documented in a report using the enclosed AccuWin Pro™ software. The results of ambulatory blood pressure testing provide the most comprehensive representation of a patient’s complete blood pressure profile.
24-hour ambulatory blood pressure monitoring (ABPM)
Ambulatory Blood Pressure Monitoring (ABPM) is when your blood pressure is being measured as you move around, living your normal daily life. It is normally carried over 24 hours. It uses a small digital blood pressure machine that is attached to a belt around your body and which is connected to a cuff around your upper arm. It small enough that you can go about your normal daily life and even sleep with it on.
Why might I need a 24-hour monitor?
By measuring your blood pressure at regular intervals over 24 hours, your doctor is able to get clear pictures of how your blood pressure changes throughout the day. There are a number of reasons why your doctor might suggest this test:
- They may want to find out if your high blood pressure readings in the clinic are much higher than they are away from the clinic (called the “white coat effect”).
- They may want to see how well your medicines are working, to make sure they are controlling your blood pressure through the day.
- They may want to see if your blood pressure stays high at night. If this is the case, they may need to change or adjust your medicines.
What happens during 24-hour blood pressure monitoring?
Normally the machine is fitted at your local hospital outpatients department, although some GP surgeries may have their own.
A 24-hour blood pressure measurement is just the same as a normal blood pressure check: a digital machine takes your blood pressure by inflating a cuff around your upper arm and then slowly releasing the pressure. The machine is small enough to be worn on a belt on your waist while the cuff stays on your upper arm for the full 24 hours.
The machine then takes blood pressure readings at regular intervals throughout the day: usually, every 15-30 minutes during the daytime and 30-60 minutes at night. You will need to keep the monitor on through the night – you could put the machine under the pillow or on the bed while you sleep.
Because the test is being carried out to find out what your normal daily blood pressure is, it is important to carry on with your normal routine and do all the things you would normally do. The only things you should avoid doing for the day are swimming and having a bath or shower.
At the end of the 24 hours you can remove the machine and cuff and give it back to the hospital or surgery. The machine will have stored all your readings and these will then be analysed.
What do I need to do during 24-hour blood pressure monitoring?
To allow the machine to work properly, it is important to make sure that the tube to the machine is not twisted or bent. Also, just before the machine is about to take a reading, it will beep. When this happens you should:
- sit down, if possible
- keep the cuff at the same level as your heart
- keep your arm steady.
- You will also be asked to keep a diary of what you were doing just before the reading was taken, what time you went bed and got up and if and when you took medications. Some people find 24-hour ABPM distracting and uncomfortable: if you feel like this when the readings are being taken, speak your doctor or nurse as it may affect your reading.