Patient information:

High blood pressure (BP) puts an increased load on the heart, brain, kidneys and other organs.  If untreated, it can lead to heart attack, heart failure, kidney failure and stroke.  High BP usually has no symptoms, so accurate diagnosis by screening is very important.

Blood pressure monitoring can be very helpful to determine if a person does have genuinely high BP (it is often higher than normal under stressful conditions, such as visiting the doctor - known as 'white coat hypertension'), or to see how well the BP is controlled by treatment.

The ABPM procedure:

Ambulatory blood pressure (ABPM) monitors are small, battery-powered units that take blood pressure and heart rate measurements for 24 hours. The unit sits in a pouch strapped around the waist and attaches via rubber tubing to an inflatable cuff, which is wrapped around the upper arm.  An ambulatory monitor takes about 40 BP readings over 24 hours.  Your blood pressure is recorded half hourly during the day and hourly at night.  The machine can show the maximum, minimum and average BP at different times of the day.  The BP monitor saves the measurements of your blood pressure that have been captured in the 24 hours of the recording.  The blood pressure measurements are then downloaded and analysed.  This can be very helpful in tailoring the best type, and the timing of BP treatment. The recorder inflates the cuff to measure the blood pressure then deflates the cuff again.  The cuff can feel quite tight around the arm when inflated, and can briefly be uncomfortable.

My nurse will explain the procedure and fit the monitor, which takes approximately 20 - 30 minutes.  No special preparations are necessary for the test, but it is sensible to wear a loose fitting top or jacket if possible.  A diary will need to be filled in, so that BP changes can be correlated with activity during the 24 hour period. Removing the monitor the next day takes only a few minutes.  It is not possible to shower or bathe whilst wearing the unit.

After the test: 

A report is prepared showing the individual blood pressures, as well as the average, maximum and minimum BP during the day and at night.  A copy of the report is sent to the referring doctor (and to the patient themselves on request).  This is usually done within 2-4 days of the test being completed.