Measurement of blood pressure.

In order to diagnose arterial hypertension and monitor the results of treatment, there are only three research options: 

  1. Blood pressure measurement by a doctor or nurse (so-called office blood pressure measurement, as it is carried out in the doctor’s office) 
  2. 24-hour blood pressure monitoring (ABPM). A special device is used, which is attached to the patient and records blood pressure with a predetermined frequency. 
  3. Measuring blood pressure at home, both completely independently and with the help of loved ones 

At present, self-monitoring of blood pressure is, in our opinion, the best method for both diagnosing (!!!) and controlling the treatment of arterial hypertension.

It should be noted that ABPM is just as good at achieving its stated goals, but it has some drawbacks:

  • Cost (the price of daily blood pressure monitoring currently ranges from 1,000 to 3,000 rubles) 
  • Inconvenience. The device measures pressure at a specific frequency, usually twice an hour, including work and night hours. 
  • Availability issues. Not always and not everywhere this method of examination is available to the patient both economically and physically; there may not be a free device on a convenient day for you; in the region of your residence, 24-hour blood pressure monitoring is generally not available. 

Speaking about the disadvantages of ABPM, one cannot but mention its advantages. Your doctor will most likely recommend 24-hour blood pressure monitoring if it suspects one of the following situations:

  • White coat hypertension (more on this below) 
  • so-called masked hypertension – a situation in which normal blood pressure values ​​are recorded at the doctor’s appointment, and with self-control, the patient records an increased blood pressure level. In this case, ABPM allows not only to exclude the patient’s error when measuring blood pressure, but also to document the presence of arterial hypertension. 
  • Episodic and short-term rise in blood pressure. 
  • Nocturnal arterial hypertension. 

Despite the fact that we called home blood pressure measurement the best method, you should know that ABPM is today the gold standard in the diagnosis of hypertension. And here there are no discrepancies, ABPM has an indisputable advantage – it is an independent documenting of research results.

We will talk about office blood pressure measurement below, but for now we will make an important remark:

The superiority of home measurement of blood pressure over other methods of pressure control is possible only if the rules, which, in fact, are devoted to this article, are observed.

About measuring blood pressure at a doctor’s appointment 

God decided to fix things in Russian   medicine and got a job as a doctor in a polyclinic.   The first  paralyzed patient in a wheelchair comes to an appointment   God lays his hands on his head and says: get up and go.   He got up and went. He goes out into the corridor,   there is a line to the street, he is asked:  Well, how’s new?  – Yes, like all of them – I didn’t even measure the pressure. 

Oddly enough, but measuring blood pressure by a doctor at an appointment is far from the best and most accurate method of research, despite the fact that the measurement is carried out by a specialist, most often armed with a professional apparatus.

The first and, perhaps, the most important difficulty is the so-called. white coat hypertension, a situation when a person (who is not yet a patient) registers an increased blood pressure only at a doctor’s appointment. In other situations, high blood pressure is not recorded. A similar phenomenon can be observed in 15% of physician visitors (according to the results of various studies, white coat hypertension occurs in 10-20% of patients whose blood pressure is measured at the reception), which can lead to overdiagnosis and unnecessary treatment. 

Data from Mancia G, Parati G, Pomidossi G, et al. Alerting reaction and rise in blood pressure during measurement by physician and nurse. Hypertension 1987; 9: 209.
The graph shows how the blood pressure changes (the difference in mm Hg from the baseline) during the first and subsequent blood pressure measurements by the doctor and nurse. The difference between the first and third measurements exceeds 10 mm Hg.
The second, no less interesting phenomenon, is the difference between blood pressure measurements depending on who is measuring – a doctor or a nurse. The error is shown in the graphs. It decreases over time. 

The white coat phenomenon decreases in intensity over time, but still persists

Thus, blood pressure measurements at a doctor’s appointment, especially if the measurements were taken at the first appointments, should be rechecked and confirmed by control measurements at home or using a 24-hour blood pressure monitor.

About methods and apparatus for measuring blood pressure 

An apparatus for measuring blood pressure is called a sphygmomanometer or tonometer, a tonometer is a more established name, and we will use it. Modern devices use one of two methods for fixing the blood pressure level.

  • Registration of Korotkov noises 
  • Oscilloscope method 

Tonometers are of the following types:

  • Hand held mercury 
  • Manual blood pressure monitors with aneroid manometer 
  • Semi-automatic tonometers 
  • Automatic blood pressure monitors 

In hand-held tonometers, the method of fixing Korotkov’s noises is used, which is recorded by a person who measures pressure with a phonendoscope, in semi-automatic tonometers, the oscillographic method is used, when automation records the pressure in the arteries by changing (oscillating) the pressure in the tonometer’s cuff.  

Blood pressure monitors use the oscilloscope method to measure blood pressure.

Mercury blood pressure monitors are rare today. They do not have significant advantages, and the risk of mercury leakage and subsequent environmental pollution has led to the fact that in a number of countries they are simply banned.

Modern blood pressure monitors, whether aneroid manometers, semi-automatic or automatic, are comparable in both accuracy and ease of use.

The disadvantage of manual blood pressure monitors with aneroid manometer is the human factor, because the researcher records the level of blood pressure by ear, manually lowering the pressure in the cuff. It must be remembered that aneroid manometers require technical control every six months.

The disadvantage of semi-automatic and automatic blood pressure monitors is the increased error of results in arrhythmias, for example, with extrasystole or atrial fibrillation. Also, the disadvantages of automatic systems include their relatively high cost.

In semi-automatic blood pressure monitors, as well as in manual blood pressure monitors using the auscultatory method of fixing blood pressure, there is a potential additional error of 5-10 mm Hg. gives manual inflation of the cuff.

How to choose a tonometer 

The complexity of choosing a tonometer is determined, perhaps, only by a wide selection of different devices with a range of prices from several hundred rubles to several tens (!!!) thousands.

We’ll start our advice with the types of devices that we DO NOT RECOMMEND to purchase and use:

  • Mercury tonometers. Damage to the tonometer is accompanied by the risk of mercury leakage and environmental pollution (in this case, the environment is not an abstract concept, but your apartment). Considering the common human tradition to vacuum spilled mercury (which is CATEGORALLY IMPOSSIBLE to do), the acquisition of a mercury tonometer seems unreasonable. Thus, we support the rejection of the use of mercury blood pressure monitors. 
  • Finger tonometers. There are devices on the market that measure blood pressure on a finger. We cannot recommend them for use, because to date, none of the devices of this type has demonstrated the required accuracy and reliability in monitoring blood pressure 
  • Tonometers watches, tonometers-fitness bracelets
  • Not blood pressure monitors, but Currently, a number of programs for mobile devices declare the ability to measure and control pressure. None of the applications can be recommended for this purpose. 

So, we DO NOT RECOMMEND to use mercury blood pressure monitors, blood pressure monitors, various applications for gadgets.

We have decided which blood pressure monitors are best not to use, but now, from the rest, we will choose those that suit us the most. When choosing a tonometer, we suggest focusing on the following factors:

  • Economic. As noted above, the cost of blood pressure monitors on the market ranges from several hundred rubles to several thousand, there are models of cost and several tens of thousands. 
  • Social. Do you have an assistant, or, mainly, will you measure your blood pressure yourself? 
  • The presence of concomitant pathology that limits the measurement of pressure on the shoulder. 

If everything is more or less clear with the economic factor, additional explanations are not required here, then we will try to figure out the rest.

If you plan to measure pressure on your own, without outside help, then automatic or semiautomatic tonometers are the best choice. This choice is due to the fact that when self-measuring pressure by the auscultatory method, the average error is 10 mm Hg. The error, not at first glance, is small, but, considering all possible other errors, it may turn out to be significant.

The best choice for self-monitoring is automatic blood pressure monitors , the cuff of which is placed on the shoulder, but in some cases this is impossible or difficult (for example, due to surgery for breast cancer or severe obesity that does not allow choosing the optimal cuff size). In this case, there are automatic blood pressure monitors that measure blood pressure at the wrist.

Tonometers that measure pressure on the wrist are very popular, but you should be aware that the measurement error of this type of tonometer exceeds the error of conventional devices with a cuff worn on the shoulder. Also, these devices require very careful adherence to the instructions for measuring blood pressure, which, as practice shows, is not always achievable.

Accuracy! Accuracy is an option of primary interest to patients. Today automatic blood pressure monitors have the best accuracy.

Here professional associations came to the rescue, which compiled a list of blood pressure monitors recommended for home use. Let’s not reinvent the wheel and agree with these respected organizations. You can download the corresponding lists in the annex to the article.

List of devices from best to worst 

  • Automatic tonometer with a cuff on the shoulder (we buy machines that measure pressure on the wrist only when it is impossible to use a conventional device) 
  • Semi-automatic tonometer 
  • Tonometer with aneroid manometer and phonendoscope. 

When choosing specific blood pressure monitors of specific brands and models, we focus on the recommendations of professional associations (see appendix below)

Selection (selection) of the cuff 

You can get the best blood pressure monitor available, but if you choose the wrong cuff, you will get an erroneous result. Unfortunately, as practice shows, unacceptably little attention is paid to this essential component of pressure measuring devices. It is not only the length that is important, but also the width. The size of the cuff chamber should be at least 80% of the circumference of the upper arm and at least 40% of the width in length. Everything is simple here – we measure the circumference of the shoulder and select the cuff corresponding to the length.

  • Shoulder circumference from 22 to 26 cm, cuff size 12 x 22 cm (small adult cuff) 
  • Shoulder circumference from 27 to 34 cm, cuff size 16 x 30 cm (adult cuff) 
  • Shoulder circumference 35 to 44 cm, cuff size 16 x 36 cm (large adult cuff) 
  • Shoulder circumference 45 to 52 cm, cuff size 16 x 42 cm (thigh cuff) 

An error in the choice of the cuff is an error of 10 to 50 mm Hg. when measuring blood pressure. When purchasing a tonometer, do not forget to choose the correct cuff!

At what age and who needs to measure blood pressure? 
There are three indications for measuring blood pressure:

  • Screening, i.e. detection of the disease in healthy people without suspicion of arterial hypertension 
  • As part of the diagnosis of arterial hypertension 
  • To control the treatment of hypertension 

Screening start age 18 years. From this age onwards, blood pressure should be measured once a year. If you have additional risk factors, such as:

  • Obesity 
  • Hypodynamia 
  • Family history 
  • Previously recorded blood pressure above 120 mm Hg. 

measurements are made twice a year.

As part of the diagnosis and / or monitoring of blood pressure treatment, it is recommended to measure blood pressure 12-14 times a week (i.e. approximately twice a day), for two weeks, unless your doctor has recommended otherwise. Such measurements are taken every three months.

Blood pressure measurement 

What is the best time to measure blood pressure 
One of the most frequent questions from patients: at what time of day to measure pressure? There is no strict regulation on this issue. Usually, in terms of diagnosis and monitoring of treatment, your doctor may recommend 2-4 times blood pressure measurements per day. Distribute the number of measurements taking into account your daily routine, for example, one measurement in the afternoon, the second in the evening, or two measurements in the morning, two in the second. This decision will not be wrong. You will make it easier for your doctor (and therefore for yourself) if you keep a diary where you indicate the time and measurement results. 

So, if the doctor has not suggested you otherwise, then measure the pressure by distributing the measurements over the waking time.

Environmental conditions and other factors affecting the measurement result 

You should measure pressure as part of self-monitoring in a familiar environment, in a warm and quiet room.

  • Measurement in a cold room results in an upward error. For example, in one of the studies it was shown that in a cold room the error in measuring the pressure reached an average of 8-15 mm Hg. 
  • Smoking. A recently smoked cigarette can increase blood pressure by 10-20 mm Hg. If you smoke, the time from the last cigarette to the blood pressure measurement should be at least 30 minutes. The dependence of blood pressure on cigarettes is shown in the graph. 

Data from Gropelli, A, Giorgi, DM, Omboni, S, et al, J Hypertens 1992; 10: 495.

  • Bladder. A full bladder, the urge to urinate can increase blood pressure up to 20 mm Hg 
  • Extraneous noises and conversations. The room in which the research is carried out should not be noisy, the noise, the conversation of both the researcher and the subject can lead to an increase in pressure by 10 mm Hg. 
  • If you have consumed caffeinated beverages (such as tea), you should measure your blood pressure no earlier than one hour later. 
  • Also, the hour interval should be maintained after eating. 
  • Do not measure blood pressure under stress or other forms of emotional stress 
  • Refrain from physical activity before taking blood pressure measurements. 

Position in which to measure pressure 
In most studies, pressure is measured while sitting in a chair with a back. The absence of a back in the chair (or if the patient does not lean on it) can overestimate blood pressure by 10 mm Hg. The leg-to-leg position gives an error of another 5-10 mm Hg. If the forearm of the hand on which blood pressure is measured is not placed on a support (for example, on a table), then the blood pressure indicator may be overestimated by 5-15 mm Hg. Especially if the hand is tense.

Sit comfortably according to the recommendations given and sit for 5 minutes before proceeding with the measurement.

When putting on the cuff, pay attention to its positioning on the shoulder. Incorrectly worn cuff is an error in measurement reaching 20 mm Hg. The layout of the cuff on the shoulder is usually applied by the manufacturer to the cuff itself. If there is no such scheme, carefully study the instructions for the tonometer.

Which arm should be used to measure blood pressure? 
If you are measuring blood pressure for the first time in your life, then you should take a measurement on both hands. When the discrepancy between the indicators is within 10 mm Hg. in the future, blood pressure is measured on the arm on which the pressure was higher.

If the discrepancy is greater, please inform your doctor.

IMPORTANT: The hand on which the pressure is measured must be free of clothing. Sleeve should not be rolled up as this can lead to clamping of the brachial artery and significant measurement error. If you are wearing a shirt made of very thin fabric, then it is permissible to measure blood pressure by placing a cuff over it. But we strongly recommend that you free your hand from clothing. 

IMPORTANT # 2: When starting to measure pressure after a long break, measure the pressure three times in a row at intervals of one minute. Record ALL THREE recorded values ​​in your blood pressure diary.

IMPORTANT # 3: if you use semi-automatic or manual blood pressure monitors, pump air into the cuff smoothly, if you pump air very quickly or abruptly, then the error in pressure measurement can reach 20-40 mm Hg

IMPORTANT # 4: if you place the head of the phonendoscope UNDER the cuff, it will lead to an error of 3-12 mm Hg.

The arm with the cuff applied to it is at the level of the heart. Air is rapidly pumped into the cuff until the systolic blood pressure is exceeded. The achievement of this goal can be judged by the disappearance of the pulse on the arm. Then air is released from the cuff at a speed of 3-4 mm Hg per second and the moments of appearance and disappearance of Korotkoff’s noises are recorded. Too high a rate of decrease in pressure in the cuff can lead to a distortion of the result by 5-10 mm Hg.

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