Measurement of blood pressure

I have often seen home blood pressure monitoring machines in high street chemists, but they are pricey. Are they any good?

Some are, but others are not accurate or reliable. Ask your doctor for advice on which one to buy and then get it checked against the doctor's machine. Ask the nurse if you are not sure how to use it - go through a practice run in the surgery. Some doctors can loan you a machine for a couple of days. This is the best option because the most reliable electronic machines are the most expensive - a medical centre can buy one or two and keep an eye on their accuracy by regular checks, making sure the cuff is the right size and the batteries fresh. Digital monitors have a cuff, which inflates and deflates at the touch of a button. The Omron has been approved and validated but, for up-to-date advice, contact the British Hypertension Society (see Appendix 2).

How is blood pressure measured in the clinic?

Our doctor or nurse takes the blood pressure with an instrument called a sphygmomanometer (often abbreviated to sphyg). It is pronounced 's-fig-mo-man-omeater'. The Greek word for pulse is sphygmos and it is the appearance and disappearance of the pulse at the elbow that the doctor or nurse listens for (see Figure 2.5).

While your arm is relaxed and resting on a desk or supported by the doctor or nurse, a rubber cuff is wound round your upper arm just above the elbow. If your arm is large, a big cuff will be used. The cuff is attached to a column of mercury. The cuff is inflated by air being pumped into the cuff; you will feel a squeezing. The pressure in the cuff is increased until the blood flow to your hand is cut off (you may feel a tingling or numbness). Whilst the doctor listens with a stethoscope to the artery at the elbow (the brachial artery, pronounced 'brake-e-al'), the pressure in the cuff is lowered. The level of mercury shown in the column when the blood begins to flow again (felt as a thumping) is measured as the systolic pressure and, when no noises are heard (you don't feel this), it is measured as the diastolic pressure. Always ask what your reading is and keep your own records.

Getting your blood pressure checked in the surgery.

Figure 2.5 Getting your blood pressure checked in the surgery.

The mercury sphyg is being replaced by electronic measuring devices. Your practice may have changed to automatic machines but the cuff will still be put on your arm above the elbow; the wrist devices are not accurate.

How often should my blood pressure be checked?

Once a year if it is normal - try and make a note in your diary to make an appointment for the following year. If it is raised, your doctor will take several readings and keep an eye on it until it is normal. Your blood pressure will then be checked at regular intervals, usually every 3-6 months. Make sure that you ask for this measurement at least twice a year.

An electronic measuring device for blood pressure.

Figure 2.6 An electronic measuring device for blood pressure.

My doctor tells me that my systolic pressure is very high, although the diastolic pressure is normal. Does this matter?

It used to be thought that only the diastolic blood pressure rise was important, but modern research has shown that in people over the age of 45 years, the rise in systolic blood pressure over the normal of 140, and certainly over 160, is an important cause of subsequent heart disease and strokes. Treatment of this rise in systolic blood pressure is an important factor in reducing the risk of these serious complications.

Self-help

My mother had high blood pressure and she suffered a stroke when she was 65. Can I avoid having hypertension myself?

First of all, if someone in your family has had high blood pressure, make sure that you and your relatives have regular check-ups. Although you may feel no benefit now, you may help to prevent illness in the future, so adopt a positive approach: for yourself and those you care about. Other ways of helping yourself include:

• a healthy diet (see Chapter 9);

• exercise (see Chapter 10);

• avoiding getting overweight;

• avoiding excess alcohol;

• avoiding eating excess salt.

I'm 62 and my doctor is making me cut down on salt as she says that I am getting more sensitive to salt. What does this mean?

People over 60 years, African-Caribbeans and American Blacks have been found to have less tolerance to too much salt.

Salt-sensitive people can lower their systolic and diastolic blood pressure by 5-10 mmHg by cutting down on salt. Most, however, get a benefit of up to 4 mmHg, but every little bit helps to lower blood pressure and reduce the need for medication.

My husband has been told that he has a high blood pressure. The doctor gave him a diet sheet. How can a better diet help him?

Our husband should not overeat as, apart from anything else, this will make him put on weight, and being overweight is a major risk factor for and cause of high blood pressure. The single most important thing anybody with high blood pressure can do to help themselves is to lose weight. In some lucky people the raised pressure disappears completely and, in others, fewer tablets may be needed. If your husband is overweight, a reducing diet to get him to an optimum weight is an essential part of treatment. Losing 1 kg in weight could take 2 mmHg off his systolic blood pressure reading, so losing 3 kg (half a stone) can make a borderline pressure normal. However, his pressure will still need watching and will go back up again if the weight is put back on. See Chapter 9 for advice on a healthy diet and how to lose weight.

 
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