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.
Non-invasive ambulatory blood pressure monitoring (ABPM) is being increasingly used to assess patients with hypertension. This trend is supported by evidence that 24-hour blood pressure profiles may be superior to isolated clinic pressures. This is because a 24 hour reading is more reliable than a simple one off reading. Patients often experience white coat hypertension (elevated BP in the presence of a doctor) and are wrongly diagnosed with high BP. Multiple readings are useful for evaluating the effectiveness of high BP treatments in patients who have commenced medication or other therapy. It is also a useful tool for monitoring BP in patients who feel weak or who are hypotensive.
Most devices use either brachial artery microphones to detect Korotkoff sounds or cuff oscillometry where cuff pressure oscillations are detected. The measurement frequency can be varied, but it is usually between 20-30 minutes while awake and 30-60 minutes while sleeping. Patients can start or stop recordings and they can read the displayed results if they wish. Patient diaries are encouraged so that the cause of sudden changes in blood pressure can be evaluated. The units function poorly during strenuous activity and work best if the patient slows or stops moving.
A nurse will fit the monitor and explain the whole procedure. This takes approximately 10-15 minutes. No special preparations are necessary for the test, but it is sensible to wear a blouse or shirt that is loose on the arms or a short sleeved/sleeveless shirt.
You will be asked to fill out a diary indicating your activities over the 24 hour period, so that BP changes can be linked with exercise. Removing the monitor the next day takes only a few minutes. Do not shower or bathe while wearing the unit.