Measure blood pressure

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When measuring blood pressure, the doctor determines the pressure in the arteries. This depends on various factors: the flow properties of the blood, the pumping capacity of the heart and the properties of the blood vessel walls. The measurement is a safe routine diagnostic measure. Read everything about blood pressure measurement, when it is carried out and how you can measure your blood pressure correctly yourself.

What is blood pressure measurement?

Blood pressure measurement is a standard examination used to determine the pressure in the arteries (arteries). This is primarily dependent on the tension of the vascular muscles, the elasticity of the vascular wall and the amount of blood that the heart pumps into the main artery per minute. In patient files or doctor's letters, blood pressure is often referred to as "RR". This abbreviation stands for the surname of the inventor of the blood pressure cuff, Scipione Riva-Rocci.

If the doctor measures the blood pressure, he receives two values, the upper (systolic) and the lower (diastolic) blood pressure value. The systolic value arises when the heart muscle is tensed, the diastolic value when blood flows into the heart chambers again after the “heartbeat” (filling phase). The doctor gives the determined values ​​in the unit millimeter of mercury (mmHg).

Further information: blood pressure values

You can read which values ​​are normal in the various age groups in the article Blood pressure values.

When do you measure blood pressure?

Blood pressure measurement is a routine examination that is standard in a thorough medical examination. The measurement is of particular importance in patients who have an underlying disease with high blood pressure, for example hyperthyroidism, kidney disease or type 2 diabetes. Of course, the doctor regularly checks the blood pressure values ​​of heart patients.

What do you do when measuring your blood pressure?

There are two methods for measuring blood pressure:

• The indirect (bloodless) measurement of blood pressure using a blood pressure cuff
• The direct (bloody or invasive) blood pressure measurement via a catheter in an artery

When to measure blood pressure with the direct method depends on the patient's situation. The direct method allows a continuous measurement, as it is only necessary in the case of serious illnesses or injuries (intensive care unit), during operations (general anesthesia) or special diagnostic questions.

Measure blood pressure using the indirect method

In order to measure the blood pressure indirectly according to Riva-Rocci, the doctor puts an empty blood pressure cuff around the patient's upper arm and inflates it. The pressure of the cuff is ultimately greater than the arterial pressure, so the artery is squeezed and the doctor cannot hear any flow noises in the crook of the elbow with the stethoscope. Now he slowly lets the air out of the cuff and looks at the pressure indicator.

As soon as the cuff pressure falls below the arterial pressure, blood can flow through the artery again. Since the artery only widens slowly when the pressure is released, blood flow noises occur when the artery is still narrowed (Krotokow noises). The beginning of these noises marks the systolic blood pressure. If the noises disappear again when you continue to deflate, this indicates the diastolic value.

Alternatively, the doctor or nurse can measure the blood pressure with a battery-operated device. This is usually an oscillometric blood pressure measurement. The measuring device automatically inflates the cuff, releases the air and registers the vibrations of the pulsating artery. The calculated values ​​are then displayed on a small monitor. Household devices often perform this measurement on the wrist as well.

Measure blood pressure by the direct method

The doctor sticks a cannula into an artery, usually on the arm or in the groin. He connects this to a tube filled with saline solution. The blood pressure wave is passed on to a device (pressure transducer) via the fluid in the tube and the mechanical signal is converted into an electrical one. A monitor then shows both systolic and diastolic blood pressure. At the same time, the course of each individual pulse wave is displayed, which allows further conclusions to be drawn about the cardiovascular function or the fluid balance.

24-hour blood pressure measurement (long-term blood pressure measurement)

The 24-hour blood pressure measurement is not a routine examination. It is carried out when the doctor suspects blood pressure values ​​fluctuating over the course of the day and night (blood pressure usually drops slightly at night). It can also be used to determine the necessity and effectiveness of drug therapy for high blood pressure. The measurement is carried out with a portable blood pressure monitor, so the patient does not have to stay in the hospital. Usually over 24 hours, the cuff inflates itself again and again at regular intervals and measures the respective blood pressure. The recorded values ​​are saved in the device so that the doctor can evaluate them the following day.

With the 24-hour blood pressure measurement, it makes sense to document special occurrences or activities in everyday life. It is best to write down whether and when you were particularly stressed, exercised or slept. This makes it easier for your doctor to evaluate the blood pressure values.

How can I properly measure my blood pressure myself?

Many patients also have to regularly measure their blood pressure themselves at home as a check-up. This is quite easy with the usual blood pressure cuffs. It is best to have your family doctor show you the correct procedure.

You should consider the following when measuring your blood pressure:

• As standard, blood pressure is measured while sitting.
• Do not take the measurement stressed and in a hurry.
• You should sit calmly and relaxed at least five minutes beforehand.
• Make sure the cuff is deflated and apply it at heart level.
• If you are taking the measurement on your wrist, keep your wrist at the level of your heart.
• When measuring on the hanging upper arm, the cuff is automatically at the level of the heart. However, the arm should be slightly bent. It is usually sufficient to rest your arm relaxed on the table.
• Do not make any major movements during the measurement as this can falsify the values.
• Make sure you have the correct size cuff. Cuffs that are too narrow measure incorrectly high values, too wide incorrectly low values. It is best to measure the circumference of your upper arm. Half of that is a good measure of the cuff width.
• For better follow-up control, it is advisable to carefully write down the values ​​determined by measuring your blood pressure in a notebook and take it with you when you visit a doctor.

Most devices also measure the pulse. You should also note this down. Some devices also detect an irregular heartbeat. If you do not know this or if the heart is beating significantly faster than usual, you should consult a doctor immediately (especially if you have any further symptoms). Before doing this, however, you should measure again, for example feeling the pulse with your hand, in order to rule out incorrect measurements.

How do I find the right measuring device?

Unfortunately, many commercially available measuring devices only provide unreliable values ​​that do not allow optimal control of blood pressure. The German Hypertension League therefore regularly tests various models and awards official seals of approval for their measurement accuracy. A list of recommended measuring devices with which you can reliably measure your blood pressure can be found on the website of the German Hypertension League.

Measure blood pressure without a device?

Blood pressure cannot be measured without the aid of special devices. So if you don't have a measuring device, only the pulse provides information about the patient's circulatory situation. The blood pressure cannot be calculated or estimated in this way, because a patient with a low pulse can also have high blood pressure and vice versa.

What are the risks of measuring blood pressure?

The indirect measurement method is completely harmless and does not involve any risks for the patient. The arterial blood pressure measurement via a catheter, on the other hand, is a minimal but invasive measure. The patient should therefore be informed about the following risks of this procedure:

• Artery occlusion with insufficient supply of the tissue
• Bleeding from the cannula
• Bleeding from the puncture site after removing the catheter
• Infections

What do I have to consider after measuring my blood pressure?

If you or the doctor use the indirect method to measure blood pressure, there are no special precautions to be followed. After all, it is a completely safe routine examination.

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