What is ambulatory blood pressure monitoring?

What is ambulatory blood pressure monitoring?

എന്താണ് ആംബുലേറ്ററി രക്തസമ്മർദ്ദ നിരീക്ഷണം?

Usually blood pressure is measured as two or three values in the clinic or at the bedside. Blood pressure is known to fluctuate through out the day depending on your activities and stress. So a recording from the clinic may not reflect the average blood pressure during a 24 hour period. Studies have shown that average daily blood pressure is more important than single recordings in deciding the damage to the heart and blood vessels due to high blood pressure.

In ambulatory blood pressure monitoring, a cuff applied to the arm is automatically inflated and deflated periodically by a battery driven device attached to the belt. Recordings may be programmed at 15-30 minute intervals. Intervals at night may be programmed higher to facilitate sleep. After a 24 hour period, the device is removed and connected to the computer with ambulatory blood pressure monitoring software. The system gives a computer analysis and print out of the average daily blood pressure, average day time blood pressure and average night time blood pressure. Heart rate and blood pressure trends may also be printed.

As per the guidelines of the American Heart Association, confirming of a diagnosis of hypertension (high blood pressure) by ambulatory monitoring is strongly recommended. In most persons the systolic blood pressure (blood pressure when the heart contracts and pumps out blood) decreases 10% to 20% during sleep. They are called “dippers”. There are also “non-dippers” and few in whom blood pressure may even rise during sleep.

There are certain persons whose blood pressure increases with the anticipation of measurement in the health care setting, but are normal in other situations. This is known as “White coat hypertension”. They will not have damage to the organs due to high blood pressure and need no treatment. But now there is a view that they need surveillance as they might develop sustained high blood pressure later.

Then there is a group who have elevated blood pressure when recorded from home, but have normal blood pressure recorded in the health care setting. This is known as “Masked hypertension” and has the same risk as sustained hypertension. Finally, there is the more common situation who have elevated blood pressure recording while at home as well as the clinic. That is known as sustained hypertension. Sustained hypertension is associated with damage to heart and kidneys.

Ambulatory recordings are useful in identifying these different subgroups of hypertension. Response to medications can also be assessed with ambulatory blood pressure recordings. It will tell us whether the medication is controlling the elevated blood pressure throughout the day or only at certain times of the day. Blood pressure elevations in pregnant women and in those with borderline hypertension can also be assessed by ambulatory recordings. When some other medications produce changes in blood pressure, that also can be identified by ambulatory recording. It may be also be useful in those who get fainting episodes with low blood pressure. Here the ambulatory recordings help to correlate symptoms with corresponding blood pressure level.

Repeated recordings during ambulatory monitoring may produce some discomfort to the person due to repeated cuff inflation. Some soreness or rashes may also appear at the site of cuff application. But these are self limited problems which will disappear in a day or two. Cuff inflations at night might interfere with sleep and that is why the measurement interval is usually programmed longer at night.