Your doctor may ask you to start taking your blood pressure at home and recording it. Doing so will give both you and your doctor a more complete understanding of how much your blood pressure varies during the day, and how well your medication is working to control your con- dition. It also eliminates the “white-coat hypertension” factor (see page
39), which can complicate the process of diagnosis. Self-measurement is never a substitute for having your blood pressure checked by a health- care professional; it complements and con?rms the measurements taken at your doctor’s of?ce. If there is a large discrepancy between readings at home and in the doctor’s of?ce, bring in your home blood pressure monitor for your doctor or nurse to check for you.

You will need to purchase a blood pressure monitor (see below) that you feel comfortable using at home. You can ?nd a selection of these devices at any pharmacy or medical supply store. You may wish to learn more about them by reading a consumer review magazine, and your doctor can help you decide which one will work best for you. You can choose between two basic types: a digital monitor or an aneroid monitor.

Digital Monitors

A digital, or automatic, monitor is the most popular blood pressure measuring device because it is easy to use. The gauge and the stetho- scope are in one unit, the digital screen is easy to read, and the de?ation is automatic. You can choose between an automatic or a manual in?a- tion device. The chance of human error is much less than it is when using an aneroid monitor. To use a digital monitor, follow these steps:
1. Place the cuff around your upper arm. Turn on the machine.
2. Push the button to activate the in?ation device, or squeeze the hand bulb on a semiautomatic model. After the cuff is in?ated, the instrument will automatically start to de?ate.
3. Look at the digital screen to see your reading. Both your systolic and diastolic measurements will appear. Write the numbers down, with the systolic reading over the diastolic reading.
4. Press the exhaust button to fully de?ate the cuff.
5. If you want to repeat the measurement, wait 2 or 3 minutes.
A drawback of the digital monitor is that it is highly sensitive, and body movements or an irregular heartbeat can affect its accuracy. Be careful about the placement of your arm and application of the cuff. The device requires batteries and needs factory repair or readjustment when problems arise. Digital monitors are somewhat more expensive than aneroid devices, depending on what model you choose. A fully automatic model may be twice the cost of an aneroid device, and the most expensive ones can be several hundred dollars.

Aneroid Monitors

An aneroid, sometimes called a spring gauge, monitor is relatively inexpensive, lightweight, and portable. (Aneroid means “containing

no liquid.”) Some cuffs have a built-in stethoscope, which is easy to work with. The gauge has a round dial that indicates the amount of pressure in the cuff, and you can read it easily in just about any posi- tion, as long as you are looking directly at it. Some models have a large, easy-to-read gauge, a cuff with a ring closure for one-handed use, and a de?ation valve that works automatically. To use an aneroid monitor, follow these steps:
1. Put the earpieces for the stethoscope into your ears, with the ear- pieces facing forward.
2. Extend your arm at about the level of your heart on a table or a chair arm, and wrap the cuff snugly around your upper arm, with the lower edge of the cuff about an inch above your elbow. Place the dial where you can see it clearly.
3. Place the stethoscope disk on the inner side of your elbow crease
(over the pulse).
4. Rapidly in?ate the cuff by squeezing the rubber hand bulb to a reading 20 or 30 points above your last systolic (top) measure- ment. (In?ating the cuff a little at a time gives an inaccurate read- ing.) When you stop pumping, you will not hear any pulse sound because the cuff is temporarily stopping the ?ow of blood through your artery.
5. De?ate the cuff slowly (about 2 or 3 mm Hg per second on the dial). Keep your eye on the dial and listen carefully for the ?rst sound of the blood ?ow returning. Write down the number the pointer is on; that is your systolic blood pressure.
6. Continue de?ating the cuff. Listen until you no longer hear your heartbeat, and note the reading. This number is your diastolic blood pressure.
7. Record the numbers with the systolic reading over the diastolic reading (for example, 140/80).
8. If you want to repeat the procedure to con?rm your reading, wait
2 or 3 minutes before you rein?ate the cuff.
There are some disadvantages to using an aneroid monitor. It is a fairly delicate, complex device that can be easily damaged. You will need to have it checked for accuracy at your doctor’s of?ce or pharmacy at least once a year, or if you drop it or bump it. If it is damaged, it will need factory repair. It may be dif?cult to use if your hearing or sight is impaired, or if you have dif?culty squeezing the hand bulb.

Other Types of Monitors

You may see mercury monitors, which are considered the standard for blood pressure measurement. The mechanism is simple and works by gravity, giving consistent, accurate readings. However, a mercury monitor is generally not recommended for home use because of the danger of mercury spills. The device has a long glass or plastic mercury tube that must be carefully protected against breakage. The device is bulky and must be kept upright, and the gauge must be read at eye level. It is dif?cult to use if you have a hearing or vision impairment.
You may see ?nger or wrist monitors that look convenient. These devices are not very accurate, however. They are highly sensitive to position and body temperature and are usually significantly more expensive than other types of monitors.
You can also buy portable devices that continuously monitor and record your blood pressure day and night. For some people, this method is the most effective way to get a clear picture of blood pressure variances and the effect of medications. Your doctor will tell you whether you require this type of monitoring.

Take your time making your choice about what kind of home moni- tor to buy. Talk to your doctor about which kind is most suitable for you. As you shop, consider these features:
• Cuff size. Cuffs come in different sizes—including children’s models—and the right size is very important for accurate meas- urement. Your doctor’s of?ce or pharmacy can tell you what size you will need. If you need a size that is not standard, it can be ordered for you.
• Readable numbers. Be sure that the numbers on the gauge are easy for you to read.
• Cost. Do not assume that the most expensive is the best. You have many models to choose from and a wide price range. The most important consideration is accuracy.
• Care and storage. Some models may require storage in a certain position, protection from bumps, or protection from heat.
After you have bought a device, take it to your doctor’s of?ce and have it tested for accuracy. Ask a health-care professional to show you exactly how to use it and what to do if you get an elevated reading. Find out how to get your device checked and recalibrated periodically.