Stages of blood pressure measurement. Overview of informative methods for measuring blood pressure

Measurement of blood pressure is an important diagnostic method of examination. Measurement of blood pressure is considered by physicians as the main pre-medical procedure, which, if necessary, it is important to be able to do it yourself at home.

Apparatus for measuring pressure

For these purposes, a special apparatus for measuring pressure, called a tonometer, is used. It consists of the following elements:

Sphygmomanometer;
Pressure gauge.

The main parts of the sphygmomanometer are a rubber cuff for clamping the artery and a balloon (pump) for injecting air. Manometers are spring and mercury.

Usually, tonometers are used to measure blood pressure using a stethoscope (stethoscope, phonendoscope). The measurement is made according to the auditory Korotkov method.

Basic rules for measuring blood pressure

Blood pressure must be measured, observing the following rules:

1. The room should be warm;

2. The patient should sit comfortably or lie on his back. Before measuring pressure, a person should rest for 10 to 15 minutes. It should be noted that in the supine position, the pressure is usually 5-10 mm lower than when measured in a sitting position;

3. Directly during the measurement of blood pressure, the patient must remain calm: do not talk and do not look at the pressure measuring device itself;

4. The patient's arm should be completely bare, the palm should look up and be located comfortably at the level of the heart. The raised sleeve of clothing should not put pressure on the veins. The patient's muscles must be absolutely relaxed;

5. The rest of the air is carefully expelled from the cuff of the pressure measuring device;

6. Tightly put the cuff on the arm, while not tightening it too much. The lower edge of the cuff should be located 2 - 3 cm above the bend in the elbow. Then the cuff is tightened or connected with Velcro;

7. A stethoscope is attached to the inner dimple on the elbow, tightly, but without pressure. It is best if it is with 2 ears and rubber (polyvinyl chloride) tubes;

8. In complete silence, with the help of a balloon of the device for measuring pressure, air is gradually pumped into the cuff, while the pressure in it is recorded by a manometer;

9. Air is pumped until the tones or noises in the ulnar artery stop, after which the pressure in the cuff is slightly increased by about 30 mm;

10. Now the air injection is stopped. Slowly opens a small tap at the cylinder. The air starts to come out gradually;

11. The height of the mercury column (the value of the upper pressure) is fixed, at which a clear noise is heard for the first time. It is at this point that the air pressure in the pressure monitor decreases compared to the pressure level in the artery, and therefore a wave of blood can enter the vessel. Thanks to this, a tone is called (by sound it resembles a loud pulsation, a heartbeat). This value of the upper pressure, the first indicator, is an indicator of the maximum (systolic) pressure;

12. As the air pressure in the cuff decreases further, vague noises appear, and then tones are heard again. These tones gradually increase, then become clearer and more resonant, but then suddenly weaken and completely stop. The disappearance of tones (sounds of the heartbeat) indicates an indicator of the minimum (diastolic) pressure;

13. An additional indicator detected when using pressure measurement methods is the magnitude of the pulse pressure amplitude or pulse pressure. This indicator is calculated by subtracting from the maximum value (systolic pressure) the minimum value (diastolic pressure). Pulse pressure is an important criterion for assessing the state of the human cardiovascular system;

14. The indicators obtained using pressure measurement methods are recorded as a fraction separated by a slash. The top number is the systolic pressure, the bottom number is the diastolic pressure.

Features of pressure measurement

When measuring blood pressure several times in a row, you need to pay attention to some features of the body. Thus, the values of indicators during the subsequent measurement, as a rule, turn out to be slightly lower than during the first measurement. Excess of indicators at the first measurement can be caused by the following reasons:

Some mental excitement;
Mechanical irritation of the nervous network of blood vessels.

In this regard, it is recommended to repeat the measurement of blood pressure without removing the cuff from the arm after the first measurement. Thus, applying pressure measurement methods several times, as a result, average indicators are recorded.

The pressure in the right and left hand is often different. Its value may differ by 10 - 20 mm. Therefore, doctors recommend using methods for measuring pressure on both hands, and fixing the average values. Measurement of blood pressure is carried out sequentially on the right and left hands, several times, and the obtained values are then used to calculate the arithmetic mean. To do this, the values of each indicator (separately the upper pressure and separately the lower one) are added and divided by the number of times the measurement was made.

If a person has unstable blood pressure, measurement should be done regularly. Thus, it is possible to catch the connection of changes in its level due to the influence of various factors (sleep, overwork, food, work, rest). All this must be taken into account when applying pressure measurement methods.

Normal values, when using any method of measuring pressure, are pressure indicators at the level of 100/60 - 140/90 mm Hg. Art.

Possible mistakes

It must be borne in mind that sometimes between the upper and lower pressure, the intensity of the tones can weaken, at times significantly. And then this moment can be mistaken for too high pressure. If you continue to release air from the device for measuring pressure, the volume of the tones increases, and they stop at the level of the present lower (diastolic) pressure. If the pressure in the cuff is not raised enough, it is easy to make a mistake in the value of the systolic pressure. So, in order to avoid mistakes, you need to use the methods of measuring pressure correctly: raise the pressure level in the cuff high enough to “press”, but releasing air, you need to continue listening to the tones until the pressure drops completely to zero.

Another error is also possible. If you strongly press the brachial artery with a phonendoscope, in some people the tones are heard to zero. Therefore, you should not press the head of the phonendoscope directly on the artery, and the value of the lower, diastolic pressure, must be fixed by a sharp decrease in the intensity of tones.

Blood pressure is considered an important indicator of the functioning of the circulatory system. This term refers to the pressure that is formed by the pressure of blood on the walls of blood vessels. There are different methods for measuring blood pressure. All of them have certain advantages and disadvantages. Which method is better to use, the doctor must decide, depending on the individual characteristics of the organism.

Conditions for correct measurement

To correctly assess blood pressure, you need to follow a number of recommendations:

Measurements should be taken in a calm state. This is best done at room temperature.
Smoking, alcohol and caffeine must be stopped 1 hour before the procedure. Also, do not play sports.
The measurement is carried out after the person rests for 5 minutes. If before the procedure the patient was subjected to emotional or physical overload, this interval is increased to half an hour.
Pressure can be measured at different times of the day. Feet should be placed on the floor, and hands should be relaxed. They should be placed on the same level as the heart.

Ways to assess pressure

The main ways to measure blood pressure include:

Direct - usually used in surgical practice. He needs vascular catheterization and the use of special solutions.
Indirect - is divided into auscultatory and palpatory. There is also an oscillometric method. Such techniques involve the use of special devices - tonometers.

Typically, pressure is assessed in the brachial artery by inserting a catheter into it. They can also place a phonendoscope in the fossa of the elbow. A person must relax in order to achieve accurate parameters.

The pulse is heard due to the vibration of the walls of blood vessels. This manifests itself in the form of blows. The procedure must be performed several times, taking a break of 2-3 minutes.

If a person has vascular abnormalities, pressure is measured on the arteries of the thigh. In such a situation, the patient is placed on the stomach, and the device is placed in the area of the popliteal fossa.

Invasive way

This is a direct way to evaluate indicators. For its implementation, a cannula is placed in the lumen of the vessel. You can also use a catheter for this purpose. The procedure is used when there is a need for continuous evaluation of blood parameters.

When choosing a vessel for measurement, consider the following factors:

the area must be easily accessible;
body secretions should not fall into this area;
vessel and cannula must match each other in diameter;
There must be sufficient blood flow in the artery to avoid blockage of the artery.

The radial artery is usually chosen for invasive blood pressure measurement. This vessel is easily palpable, does not affect the level of movement of the patient and is located on the surface.

To determine the condition of the artery and evaluate the blood circulation in it, an Allen test is performed. For this, arteries are compressed in the cubital fossa. Then they ask the person to clench his fist until his hand turns pale.

After that, the arteries are released and it is determined over what time interval the color of the hand returns to normal:

5-7 seconds - indicates normal blood flow in the artery;
7-15 seconds - is considered an indicator of circulatory disorders;
more than 15 seconds - is the basis for refusing the procedure.

The manipulation must be carried out under conditions of complete sterility. First you need to treat the system with saline, adding 5000 IU of heparin to it.

Auscultatory method

Indirect methods for determining pressure are quite simple and do not require special skills. This method is considered the most common and can be used at home.

For the procedure, a manual tonometer is used, which includes a cuff and a phonendoscope. It is important that the cuff covers the arm freely enough - a finger must pass through it. Before taking measurements, it is recommended to bare the forearm. You can also measure blood pressure through a thin tissue.

The phonendoscope is placed in the cubital fossa. An artery is located in this area, which causes a strong pulsation. It is she who is heard when using a phonendoscope.

To take measurements, the device should be inserted into the ears, close the valve on the pear and squeeze it intensively. This is required to inflate the cuff. This must be done until the pulse disappears. Then you need to perform a few more squeezes to raise the arrow by 20 points.

After that, you can gradually release the air. It is recommended to do this very slowly, unscrewing the valve on the pear. At this time, you need to be especially attentive to hear the first and last blows. At the first knock, the upper pressure is fixed, the last knock shows the lower pressure.

If it was not possible to hear the blows or there are doubts about the correctness of the procedure, it must be repeated. A person must make several movements with his hand, after which you can return to the measurements.

In an adult, the normal blood pressure is 120/80 mm Hg. Art. Small deviations are also allowed. Systolic pressure can be in the range of 110-139, diastolic - 60-89.

Palpation method

This method of measuring blood pressure also involves the use of a pneumatic cuff, but the procedure is not carried out using a phonendoscope, but by determining the pulse.

To do this, you must perform the following steps:

Place the cuff on your forearm just above the crease of your arm and inflate it with air.
Press the radial artery with your fingers.
When the first contraction occurs, it is worth fixing the indicator - it indicates the upper pressure. The last ripple indicates the lower parameter.

This technique is usually used for young children when it is not possible to use the auscultatory method. In the same way, you can determine the indicator on the femoral artery.

To do this, the cuff is put on the thigh, filled with air, and then slowly lowered. The pulse should be felt in the region of the popliteal artery. This will help determine the top pressure. It should be borne in mind that the upper pressure indicator when assessed by this method will be 5-10 points lower than when using the auscultatory technique.

Oscillometric method

This method can be easily applied at home. To do this, you need to familiarize yourself with the rules for using the device. The oscillometric method involves the use of an automatic or semi-automatic device. He will independently determine the indicator and display it on the monitor.

Depending on the method of air injection, such tonometers can be mechanical and automatic. In the first case, the patient must independently pump air. When using an automatic device, the air inflates the cuff on its own.

This technique has certain features. When it is applied, the blood pressure in the cuff does not fall smoothly, but in steps. At the time of stops, the device determines the pressure and pulse.

Determination of pressure in different groups of patients

The procedure for measuring pressure is determined by the individual characteristics of the patient's body. This must be taken into account when choosing a particular technique.

In the elderly

Age-related changes lead to instability of pressure indicators. This is due to a violation of the blood flow regulation system, a decrease in the elasticity of blood vessels, and the development of atherosclerosis. Therefore, older people need to perform a whole series of measurements and calculate the average.

In addition, they need to take measurements in a standing and sitting position. This is due to a sharp decrease in pressure at the time of a change in posture - for example, when getting up in bed.

In children

Children should measure their blood pressure with a mechanical sphygmomanometer or an electronic semi-automatic device. In this case, it is worth using a children's cuff. Before carrying out the procedure on your own, you need to consult a pediatrician.

In pregnant women

Blood pressure indicates the nature of the course of pregnancy. Expectant mothers need to constantly monitor this indicator. This will help to start therapy in a timely manner and prevent the development of complications.

During pregnancy, the pressure is measured in a reclining state. If the indicator is more than normal or significantly lower, you should immediately consult a doctor.

Common Mistakes

Many people make a number of mistakes when assessing blood pressure. These include the following:

insufficient period of adaptation to hospital conditions;
incorrect position of the hand;
the use of a cuff that does not match the size of the shoulder;
high rates of air deflation from the cuff;
lack of assessment of the asymmetry of indicators.

There are quite a few methods for measuring pressure. Each of them has certain advantages and disadvantages. To choose the optimal procedure, you need to take into account the patient's state of health and the individual characteristics of his body.

The work of the heart and the movement of blood through the vessels are accompanied by rhythmic changes in the volume of arterial vessels and the level of blood pressure. Therefore, knowledge of the level of blood pressure, its pulse fluctuations is very important for assessing the functional state of the circulatory apparatus. For the first time, the measurement of blood pressure in animals was carried out by Gales in 1733. For this purpose, he tied a brass tube into the artery, connected by a rubber hose to a vertically mounted glass tube. The horse's blood rose 8-9 feet, the dog's 4 feet. Poiseuille, assuming that Thales' data was incorrect, used a U-shaped mercury manometer connected to the artery with a rubber hose to measure blood pressure. Since then, blood pressure has been expressed in millimeters of mercury.

For a pressure of 1 mm Hg. Art./cm2 in honor of Torricelli adopted the symbol "torr". Poiseuille found that the blood pressure in a horse is 159 Torr, in a dog 151 Torr (or mm Hg/cm2).

Fig.1.

With the help of a Poiseuille manometer, Febvre in 1856 first measured the blood pressure in a person during amputation of the thigh and found it to be 120 Torr (mm Hg / cm2).

In 1876, Marey (Mareu) proposed an indirect method for determining blood pressure in humans. He placed the subject's forearm in a plethysmograph filled with warm water (Fig. 1). The plethysmograph O was connected to the tank P, suspended on block B and filled with water, and to a mercury manometer M with a float and a scribbler, with the help of which the change in pressure in the plethysmograph was recorded on the smoked tape of the kymograph K.

When the pressure in the oncometer reaches a value corresponding to the minimum pressure, the oscillation amplitude increases and continues to grow. At the so-called average dynamic pressure, the oscillations reach a maximum. Then they begin to gradually decrease until the moment corresponding to the systolic value. At this moment, the amplitude decreases abruptly (Fig. 2a).

Rice. 2 (a and b).
Designations: Mn - minimum, Cp - average, Ks - final systolic pressure; the numbers indicate the pressure in torr, other designations in the text

Marey's method required complex and fragile equipment, but nevertheless at first it seemed promising, since it made it possible to determine the value of the average dynamic pressure. However, the imperfections of the methodology limited the possibilities of using this method, and soon interest in it significantly weakened. The reason was that the method of reading, or decoding, waveforms proposed by Marey gave unsatisfactory results. On fig. Figure 2a shows a typical (according to Marey) oscillogram shape, which, according to Gley and Gomez (1931), was obtained only in 25% of all cases, and in fig. 2b - the most frequently obtained oscillogram, occurring in 75% of cases. It was not possible to decipher the last curve.

A fundamentally new technique for determining blood pressure was proposed by Riva-Rocci (Riva-Rossi, 1896). It consisted in compressing the brachial artery with a special rubber cuff 4-5 cm wide and 40 cm long, enclosed in a silk fabric case. The cuff was connected to a mercury manometer of the original design, and air was injected into it using a balloon. The magnitude of blood pressure was judged by the moment of disappearance and then the appearance of a pulse on the radial artery, respectively, during the rise and fall of pressure in the cuff, taking the average from these readings. As shown by numerous studies, the Riva-Rocci blood pressure values significantly exceeded its true value. According to Recklinghausen (Recklinghausen, 1901), errors in pressure determination decrease with increasing cuff width, and the best results can be obtained with a cuff width of at least 12 cm. According to Riva-Rocci, only systolic pressure was determined. In 1905 N.S. Korotkov, at an interdepartmental meeting of the Military Medical Academy, reported on the sound phenomenon he had discovered that occurs when the brachial artery is squeezed by the cuff. M.V. Yanovsky correctly assessed the practical significance of N.S. Korotkov and subjected him to a comprehensive study.

Thanks to the works of M.V. Yanovsky method N.S. Korotkov received universal recognition and firmly established in clinical practice around the world. The advantage of the sonic method is its simplicity and accessibility, it allows you to determine the value of not only the maximum, but also the minimum pressure.

The works of M.V. Yanovsky et al found that if the pressure in the cuff is raised above the systolic one and then gradually reduced, then at the moment of falling to a value approximately equal to or slightly less than systolic, tones appear in the distal segment of the artery - the first phase of the Korotkov phenomenon. With a further decrease in pressure in the cuff, the tones are replaced by noises - the second phase of "Korotkov" sounds. In the future, loud tones appear again - the third phase of the phenomenon, then their intensity decreases - the fourth phase, and, finally, the sounds disappear - the fifth phase.

A typical alternation of sound phenomena is not always observed. The noise phase is often absent. With high blood pressure, it is often possible to observe the appearance of tones of the first phase, which then disappear and reappear when the pressure in the cuff decreases by another 10-20 mm Hg. Art. - the phenomenon of "failure". In the future, the sounds change in the usual way.

The sound phenomenon is especially atypical if the pressure in the cuff is gradually increased. Often, a sound, sometimes very faint, appears only at the moment when the pressure in the cuff reaches systolic. If you raise the pressure higher and then lower it, then all phases of the N.S. Korotkov’s sounds can be distinct, i.e., in the same subject, the sound phenomenon may be absent during compression and be well expressed during decompression.

The time during which the measurement of pressure according to N.S. Korotkov, should not be long - no more than one minute.

A large number of experimental and clinical works are devoted to clarifying the question: to what extent is the pressure determined by N.S. Korotkov, corresponds to the true values of blood pressure (Frank, 1930; Bonsdorff and Wolf, 1933; G. I. Kositsky, 1958; Kenner and Gauer, 1962). These studies consisted in comparing the data obtained by the method of direct direct measurement of blood pressure (arteriopuncture), with the data obtained by measuring arterial pressure by the sound method. It should be considered that when determining arterial pressure at rest, the appearance of the “Korotkovsky” sound during decompression quite accurately coincides with the value of the final systolic pressure, exceeding the value of the lateral systolic pressure by 10–15 mm Hg. Art. (torr). With regard to diastolic pressure, the question is still being discussed - whether the true value of diastolic pressure corresponds to the fourth phase of the "Korotkov" sounds, i.e. the moment of transition of loud sounds to quieter ones or the fifth phase, i.e. the disappearance of sounds. The American Heart Association believes that when diastolic pressure is determined at rest, by the moment when loud sounds turn into soft sounds, values \u200b\u200bare obtained that are 7-10 Torr (mm Hg) higher than diastolic pressure. When determined by the moment of disappearance of "Korotkov" sounds, the readings coincide with those obtained by the direct method.

The determination of blood pressure according to Korotkov-Yanovsky requires strict adherence to certain conditions. It should be carried out at rest, in a comfortable position for the study (lying or sitting). The arm should be slightly bent and placed at the level of the heart. Since 1925, the attention of researchers, especially in France and Germany, to the oscillography method proposed by Marey (Frank, 1930; Bromser, 1928; A.I. Yarotsky, 1932) has again increased. However, the imperfection of the technique limited the possibility of using oscillography. Subsequently, all oscilloscopes designed to determine blood pressure were built using the principle of a differential pressure gauge, but they were distinguished by a low natural frequency of the recording system and low sensitivity. The quality factor of the recording system has been significantly improved by using optical recording of mechanical movements. The optical method made it possible to significantly increase the sensitivity of the instrument.

In 1935 N.N. Savitsky, together with the staff of the Leningrad Institute of Fine Mechanics and Optics, developed a new type of very sensitive optical differential pressure gauge. The merit of N. N. Savitsky is that he developed in detail and scientifically substantiated a completely new method for reading oscillograms. He called the differential oscillogram obtained with the help of the device he created a tachooscillogram (tachus - fast, fast; oscillum - swing, oscillation; gramma - record) to emphasize that it is the first time derivative of the volumetric one. The tachooscillographic method for determining blood pressure differs from other oscillographic methods in that it is not changes in the volume of the vessel located under the cuff that are optically recorded, but the rate of these volumetric changes. In addition, the used optical registration significantly exceeds the sensitivity of other devices available.

The method of tachooscillography has become firmly established in clinical practice. It became available to determine not only diastolic, average dynamic pressure, but also true systolic (or lateral) pressure.

As you know, when measuring blood pressure, we get two values: systolic (upper) and diastolic (lower). The ideal pressure, which, unfortunately, is quite rare among ordinary people, is considered to be 120 over 70 or 80. However, it is acceptable to increase the parameter to 140/90 or decrease to 100/60. If the indicators go beyond these values, the condition is regarded as a pathology - hypertension or hypotension.

It is desirable for a healthy person to control the level of blood pressure at least once every six months. This should be done to diagnose a pathological change in pressure, usually hypertension. Often, this disease can only be determined by measuring pressure, since the initial stage is characterized by an asymptomatic course. This is what hypertension has earned the nickname of the "silent killer", because it is not uncommon for a person to not even know about his condition. Without taking therapeutic measures, the disorder progresses, and painful symptoms appear even when.

If a person suffers from hypertension, he needs to measure his pressure twice daily - in the morning, shortly after waking up, and in the evening, before going to bed. Constant monitoring of the indicator is recommended for people with heart disease, kidney disease, cerebrovascular accident, endocrine and hormonal disorders.

Let's find out what the pressure measuring apparatus is called, how to use it, and get acquainted in detail with the methods and rules for carrying out the measurement procedure.

What devices are used to measure blood pressure

The device for measuring blood pressure is called a tonometer and is well known to all of us. All of its varieties that exist today have one common ancestor - the Riva-Rocci device developed by the Italian. At the beginning of the last century, the well-known surgeon Korotkov in Russia improved this device and created the so-called sphygmomanometer, on the mechanism of which the modern mechanical tonometer is based.

Now done with:

Mechanical tonometer- this device is considered the most accurate, but has a number of disadvantages. Firstly, it is quite difficult to use and is not suitable for self-monitoring of the parameter in the case of the elderly. In addition, the results are influenced by extraneous noise, the position and ability to use the phonendoscope, close contact of the cuff with the skin.
- to measure blood pressure, you just need to put a cuff on your arm and press the button located on the instrument panel. In this case, the device determines not only the pressure, but also the pulse rate. There are electronic blood pressure monitors with a shoulder cuff, as in a mechanical one, and there are varieties in which the cuff is worn on the wrist.

Thanks to advances and innovations in medical technology, pressure measurement is no longer a complex procedure that requires special training. Electronic blood pressure monitors make it possible to determine this indicator by simply putting on the cuff and pressing the button.

What are the ways to measure blood pressure

The procedure is performed on the inside of the arm, just above the elbow, or on the wrist. The methods differ in how pressure is measured, and on the principles of operation of these devices.

The auscultatory method - it was Korotkov who proposed it about a hundred years ago. In order to determine the level of pressure, it is necessary to pinch the brachial arterial vessel with a cuff and listen to the tones that appear when the compression is gradually weakened. The device consists of a manometer, a cuff with a balloon for injecting air and a phonendoscope for listening to tones.

This technique for measuring blood pressure involves applying a cuff to the inside of the arm, just above the elbow, and pumping air into it until the pressure level is above systolic. In this case, the artery is completely clamped, the blood stops passing through it, and the tones subside. When the air is slowly released from the cuff, the pressure becomes less, at some point the external and systolic pressures equalize, the blood flow is restored, and the noise reappears. It is these noises, which are called Korotkoff's tones, that are heard with the help of a phonendoscope. on the device at the time of the appearance of noise. When the tones cease to be heard, which indicates equal indicators of external and arterial pressures, the indicator, which at this moment is determined on the pressure gauge, corresponds to the diastolic value.

Oscillometric method - the procedure is carried out with an electronic tonometer. The principle of operation of the device is based on the fact that it itself captures the pulsation felt in the cuff, which appears when the blood flow passes through the compressed segment of the artery. The advantages of this method are, first of all, that the procedure does not require any preparation, the cuff can be worn not on a bare arm, but on a thin tissue. True, when measuring the parameter, one should not forget that the hand on which the procedure is performed should not make sudden movements.

Experts do not recommend purchasing a carpal electronic tonometer. Multiple tests show that there is a sufficient difference between the results obtained when determining the parameter with similar devices and a mechanical tonometer.

Rules for the procedure

There are a number of rules that must be followed in order to obtain accurate results:

At the time of measuring blood pressure, a person should be as calm as possible.
Two hours before the measurement, you can not eat.
You can drink caffeinated drinks, smoke, take drugs aimed at narrowing blood vessels no later than an hour before measuring blood pressure.
For two hours before the procedure, physical activity is prohibited.
When measuring, do not talk or move.

How pressure is measured

Correct measurement of blood pressure level provides for a certain algorithm of actions:

Sit the patient on a chair, invite him to lean on the back.
Release your hand from the sleeve of your clothes, put it on the table with your palm up, placing a roller folded from a towel under your elbow.
Apply a cuff a couple of centimeters above the elbow and place the arm at the same level as the heart.
Press the phonendoscope slightly to the place on the cubital fossa where the pulse is heard.
Using a pear, pump air into the cuff until the readings on the pressure gauge are two to three dozen units above the estimated upper blood pressure.
Having slightly opened the valve on the pear, begin to gradually release air from the cuff, listening to the noises in the phonendoscope.
When the Korotkoff sounds appear, the readings of the manometer correspond to the upper blood pressure, and when the tones disappear, the device shows the lower pressure.
Deflate the cuff completely.
After two minutes, re-measure blood pressure.

How to measure blood pressure with an electronic tonometer

Release your hand from clothing, put on a cuff on your forearm or wrist. In the case of a semi-automatic device, air is blown by a pear, the automatic one does everything by itself - you just need to press a button on the control panel. The result can be seen on the screen. It is also allowed to wear a cuff on a sleeve made of thin fabric.

If you use a wrist pressure gauge, be sure to remove any bracelets or watches before taking blood pressure. The hand with the cuff worn on the wrist should be placed palm down on the opposite shoulder, and the elbow rested on the free hand.

Arterial blood pressure is the pressure that blood exerts on the walls of arteries. The height of blood pressure depends on: the amount of blood entering the vascular system per unit of time; the magnitude of the outflow of blood through the precapillary bed; capacity of the vascular system; tension of the walls of arterial vessels; blood viscosity.

During the cardiac cycle, the level of blood pressure in the arteries fluctuates rhythmically, reaching a maximum at the moment when a new portion of blood enters the given section of the artery from the overlying section, which corresponds to the moment the pulse wave passes through this section. After the blood from this area has gone further to the periphery, the pressure in it decreases, reaching its minimum just before the next pulse wave passes through this area. Therefore, they distinguish:

Minimum, or diastolic, pressure - the smallest value of blood pressure in the artery at the end of the diastolic period. Its height mainly depends on the degree of permeability of the precapillary bed and the amount of blood outflow through it. The greater the resistance of the precapillary system (the greater the tone of the arterioles), the higher the minimum pressure should be. To a lesser extent, the level of the minimum pressure depends on the heart rate and the elastic state of large arterial vessels. The slower the heart rate, the longer the diastolic period and the more blood flows from the arterial system into the venous system. In this case, the minimum pressure level is reduced. The lower the elastic-viscous state of the walls of large arteries, the greater the capacity of the arterial system and the higher the minimum pressure.

The average dynamic pressure is the result of all those pressure variables that occur during one cardiac cycle. This type of pressure is not the arithmetic mean of the maximum and minimum pressure values, but lies closer to the minimum. Mathematically, this is an integral or average of infinitesimal changes in pressure during one cardiac cycle (N. N. Savitsky). While other types of pressure are temporary levels of pressure in the artery, the average dynamic arterial pressure is somewhat constant. The movement of blood through arterioles and capillaries occurs under the influence of mean arterial pressure, i.e., mean pressure expresses the energy of the continuous movement of blood from the arterial system to the venous one.

Lateral (true systolic) pressure is the pressure exerted on the lateral wall of the artery during ventricular systole.

Maximum, or systolic, pressure is a value that expresses the entire energy reserve of a moving blood column during systole. The maximum pressure is the sum of the lateral and impact pressure, i.e., the pressure that is created when an obstacle appears in front of the blood flow moving in the artery (for example, when the artery is squeezed by a cuff). Shock pressure, or hemodynamic shock, expresses the kinetic energy of a moving blood stream.

The difference between the maximum and minimum pressure is called pulse pressure. However, the true pulse pressure should be considered the difference between the lateral and minimum pressure values.

Sphygmomanometry - instrumental determination of the height of blood pressure. The most common methods of sphygmomanometric determination of the height of arterial pressure are as follows: palpation, auscultation and oscillatory. The palpation method allows you to determine only the maximum pressure, auscultatory and partly oscillatory - both maximum and minimum.

The principle underlying all these methods is that the air pumped into the hollow cuff put on the arm compresses the brachial artery until its lumen is completely closed and, consequently, blood flow stops; then gradually the air is released until the first thin trickle of blood begins to pass through the artery. Naturally, this happens when the gradually decreasing pressure on the artery becomes slightly lower than the pressure that occurs in the artery at the time of the passage of the pulse wave (maximum pressure). The height of the external pressure on the artery at this moment is determined by the indication of a mercury or spring pressure gauge attached to the cuff. The passage of the first jet of blood through the compressed brachial artery is determined by the palpation method by the appearance of a pulse in the radial artery, by the auscultatory method by the appearance of certain sounds and the artery heard below the place of compression, by the oscillatory method by the appearance of oscillations of the arrow of the spring pressure gauge.

The sphygmomanometer, most commonly used to measure blood pressure, consists of a cuff, a mercury manometer, and a system of rubber tubes connecting the manometer to the cuff. The cuff is a hollow rubber bag 12 cm wide and 30 cm long. The bag is enclosed in a cover made of unyielding dense fabric, which is necessary so that when air is pumped into the rubber bag, it squeezes the shoulder on which the cuff is applied, and does not stretch the outer wall of the bag. At one end, a rubber tube is inserted into the rubber bag. The free end of this tube is equipped with a T-shaped glass tube, one end of which is connected to the rubber tube of a hollow rubber bag, the opposite end is connected to a rubber tube leading to a pressure gauge, and the third, extending at right angles to the first two, is connected by a rubber tube to a cylinder for pumping air.

The manometer is a vessel with mercury, into which a thin glass tube is lowered at the lower end. A scale with millimeter divisions from 0 to 300 is attached to the tube, with the upper level of mercury set to zero. At the place where the rubber tube leaves the cylinder, there is a valve that allows you to either separate the cylinder and the pressure gauge and thereby keep the mercury in the manometric tube at the level reached by it after pumping air, or, conversely, connect them and thereby allow the air to exit the pressure gauge to the desired level.

In other devices, a spring manometer is used instead of a mercury manometer. Most spring gauges lose accuracy after a while. Therefore, they must be checked frequently by comparing their readings with those of a mercury manometer. The difference found between these readings must be taken into account in the further use of the spring pressure gauge.

The arterial pressure measurement technique is as follows. The cuff is put on the subject's bare shoulder as high as possible and so tightly that only one finger can be inserted between it and the skin. The edge of the cuff, into which the rubber tube is embedded, must be turned downwards. The cuff is fastened tightly on the arm or bandaged to it with ribbons. It is necessary to ensure that the zero level of mercury in the manometer cup, the artery in which the pressure is measured and the heart of the subject are at the same level. The subject's hand should be in such a position that the muscles are completely relaxed. Use a balloon to pump air into the system, which, having reached the T-shaped tube, then flows further simultaneously into the cuff and into the manometer cup. Under air pressure, the mercury in the pressure gauge rises into a hollow glass tube. The number on the scale indicates the height of the pressure in the cuff, i.e. the force with which the artery is squeezed through the soft tissues, where the pressure is measured.

When using the palpation method, simultaneously with pumping air into the system, the pulse of the radial artery is felt on the same arm of the subject. The pumping of air continues until the brachial artery is compressed through the soft tissues to complete obstruction, which is recognized by the disappearance of the pulse. Having slightly opened the valve at the place where the rubber tube leaves the balloon, they begin to gradually release air from the system, due to which the pressure on the brachial artery gradually decreases. As long as the pressure in the cuff is at least a few millimeters greater than the maximum pressure in the artery above its compression, blood cannot pass through the compressed artery, and there is no pulse in the radial artery. As soon as the pressure in the cuff falls below the maximum pressure in the artery above the place of its compression, the blood begins to flow into the opening lumen of the artery, which is recognized by the appearance of the first weak pulse beat. The level of mercury at this moment indicates the height of maximum pressure in millimeters of mercury. (In fact, this level is slightly lower than the true height of maximum pressure, but this negligible difference can be ignored). The minimum pressure is not determined by this method.

The most commonly used method at present, which makes it possible to determine both the maximum and minimum pressure, is the Korotkov auscultatory method (Korotkov's sound method). After applying the cuff to the shoulder of the subject below it in the area of the elbow bend, they look for the pulsation of the brachial artery and put a phonendoscope to this place without pressure (in the absence of it, a stethoscope can also be used, although it is short and inconvenient for listening to the brachial artery). By inflating the cuff, increase the pressure in it to a level that is higher than the expected maximum pressure. During inflation, you can listen to various sounds through the phonendoscope, which, however, disappear after the pressure in the cuff exceeds the maximum pressure in the artery. The height of the maximum pressure in each particular case is not known in advance; therefore, it is the disappearance of sounds that is an indicator that the pressure in the cuff has been raised to a sufficient height. If we now carefully release air from the cuff, then at a certain height of pressure, tones synchronous with heart contractions begin to be heard through the phonendoscope. At this point, the manometer indicates the height of the maximum blood pressure. With a further decrease in pressure in the cuff, tones that last a short time are replaced by short noises. Then they say that the first phase has ended - the initial tones - and the second phase has begun - the noise. Sometimes some noises are heard, in other cases, tones continue to be heard along with noises. Noises, which are also synchronous with contractions of the heart, at first increase more and more, then gradually weaken and, finally, completely disappear, giving way to the next, so-called third phase of tones, or the phase of final tones. These tones become stronger each time, but then sharply weaken. The manometer at the moment of cessation of tones shows the height of the minimum pressure.

The oscillatory method for determining blood pressure consists in observing the fluctuations of the arrow of a spring pressure gauge attached to the cuff. Just as with the auscultatory method, air is pumped into the cuff until the lumen of the brachial artery lying under the cuff is completely closed and then the pressure is slowly reduced, releasing air from the cuff. At that moment, when the first portions of blood begin to penetrate into the section of the artery under the cuff, the pressure gauge needle begins to oscillate (oscillate).

These fluctuations correspond to the movements of the section of the artery located below the cuff, which, when using the auscultatory method, determine the initial tones of the first Korotkov phase. The fluctuations of the manometer needle, like Korotkov's tones, first increase, and then suddenly weaken. The indication of the manometer at the moment of the appearance of the first oscillations of the arrow corresponds to the maximum pressure, and the indication at the moment of termination of oscillations corresponds to the minimum.

The oscillographic method for determining the level of arterial pressure consists in the graphic registration of the pulsation of the artery using a special apparatus - an arterial oscilloscope. Oscilloscopes of various systems with mechanical, electrical or optical recording of oscillograms are used. In clinical practice, the most commonly used ink-writing oscilloscope with mechanical recording, manufactured by the Krasnogvardeets plant. Oscillograms are recorded on a special form inserted into the cassette of the device. The recording is made when the pressure in the cuff decreases.

On the received oscillogram, three main points are distinguished: Mx - maximum, or systolic, pressure, which is determined by the first most pronounced tooth of the oscillogram; My is the average pressure, which is determined by the highest tooth of the oscillogram; Mn is the minimum, or diastolic, pressure corresponding to the last tooth of the waveform before a sharp decrease in the amplitude of the oscillation at the end of the curve. The magnitude of the greatest oscillation in mm is called the oscillatory index, which characterizes the range of pulse oscillations of the studied artery and, to a certain extent, makes it possible to judge its tone.

With the oscillographic method, typical curves are not always obtained due to the formation of the so-called plateau (oscillations of the same amplitude), which makes it difficult to establish the value of the average pressure. The tachooscillographic method proposed by N.N. Savitsky eliminates this shortcoming.

The tachooscillographic method of recording oscillograms is carried out by a mirror differential manometer, which is an integral part of the mechanocardiograph system of N. N. Savitsky. The high sensitivity of the differential pressure gauge makes it possible to register not only changes in volume, but also the rate of filling and emptying of the segment of the artery located under the cuff, and this registration is carried out at a constantly uniformly increasing pressure in the cuff. Thus, with the help of a differential pressure gauge, when graphing the pressure curve, a graphical decomposition of the rate of change of pressure over time is carried out. N. N. Savitsky developed a method for reading tachooscillograms, based on the determination of typical changes in the lower diastolic segment of the curve, which is characterized by the greatest constancy. With the help of the tachooscillographic method, in addition to the minimum, average and maximum pressure, it is possible to determine the values of the lateral and impact pressure.

It should be noted that the height of blood pressure when using all of these methods is somewhat exaggerated, since some force is expended on squeezing the soft tissues of the hand, through which the artery is compressed.

When measuring blood pressure, it should be borne in mind that in the first study in easily excitable subjects, the pressure may rise for a short time as a result of excitement. Therefore, it is recommended to measure the pressure after the subject has calmed down, or to make successive three-time measurements and derive the arithmetic mean.

Normally, in an adult, the pressure in the brachial artery is: the minimum is 60-70 mm Hg. Art., average - 80-90 mm Hg. Art., lateral - 90-100 mm Hg. Art., maximum - 110-125 mm Hg. Art., shock-10-20 mm Hg. Art., pulse - 30-45 mm Hg. Art. In children, blood pressure is lower than in adults, and in older people it is slightly higher than in young and middle-aged people.

3. M. Volynsky with co-authors deduced a certain mathematical pattern between blood pressure and age. He proposed formulas for calculating the "ideal" value of blood pressure: systolic pressure is 102 + (0.6 X age), diastolic pressure is 63 + (0.4 X age).

An increase in blood pressure compared to the norm is called arterial hypertension, a decrease in it is called arteries. al hypotension.

Hypertension. An increase in the maximum and minimum pressures, as well as their decrease, does not always go in parallel, so the value of the pulse pressure (i.e., the difference between both pressures) can change in different directions during hyper- and hypotension.

A short-term increase in blood pressure, mainly the maximum, can also be observed in healthy people after a hearty meal, after drinking alcohol, coffee, tea, during a lot of physical or mental work, especially if it is little habitual. As mentioned above, mental arousal can also be accompanied by a short-term increase in blood pressure, and the minimum pressure rises to a greater extent than the maximum.

In pathological conditions, temporary arterial hypertension can be observed with:

severe pain attacks
lead colic,
asphyxia,
tabetic crises,
injection of adrenaline
some brain tumors
sometimes with nicotine poisoning (immoderate smoking),
some people who are very overtired, especially mental work,
with eclampsia in pregnancy,
some tumors of the adrenal gland (pheochromocytoma),
sometimes with inflammatory processes in the area of the gasser node.

Persistent arterial hypertension (and, consequently, a tense pulse) is observed in glomerulonephritis, both acute and chronic. The cause of this so-called renal hypertension is considered to be the entry into the blood of renin produced in the kidneys, due to a decrease in the blood supply to the kidneys during their disease. Since this humoral increase in blood pressure also occurs with a decrease in blood supply to one kidney, the same mechanism explains the sometimes observed arterial hypertension with cystic degeneration of both or one kidney, with amyloidosis of the kidneys, hydronephrosis, pyelonephritis, compression of the ureter by tumors, with prostatic hypertrophy .

Persistent arterial hypertension is noted in hypertension, especially in its later stages. An increase in pressure at the beginning of this disease is associated with an increase in the tone of the arterioles as a result of a centrogenously tonic contraction of their muscles, and in later stages - with hyalinosis and necrosis of the arterioles, leading to difficulty in the outflow of blood from the arterial system to the venous system.

With these diseases, both the maximum and minimum pressure often increase to a high degree. The maximum pressure can, in advanced cases, rise to 250-300 mm Hg. Art., and the minimum - up to 150 and above.

A prolonged increase in maximum pressure leads to hypertrophy of the left ventricular muscle. While the hypertrophied ventricle works satisfactorily, the pulse pressure remains significant (100-120 mm Hg and above). With the weakening of the work of the hypertrophied left ventricle, the maximum pressure decreases, while the minimum pressure, which depends on the state of the lumen of the arterioles, continues to remain high, as a result of which the pulse pressure decreases. However, high maximum and high pulse pressure at a very high minimum pressure still do not say anything about the amount of useful work of the left ventricle, that is, about the amount of blood ejected by it into the aorta. The fact is that with a high minimum pressure and, consequently, with a strong tension of the vascular walls, even a small amount of blood ejected into the arterial system is enough to cause a strong increase in the maximum, and hence the pulse pressure.

With sclerosis of the ascending arch or thoracic aorta, there is an increase in maximum blood pressure with a normal or only slightly increased minimum. At the same time, due to the absence of an increase in the tone of the arterioles, the outflow of blood into the capillaries occurs normally, and therefore the minimum pressure does not increase. The maximum pressure increases, since the sclerosed aorta is not able to sufficiently stretch at the time of emptying the left ventricle, as a result of which the pressure in it, as well as in the entire arterial system, rises above normal at this moment.

Hypotension.

Sudden arterial hypotension occurs when:

shocked
collapse,
profuse bleeding,
myocardial infarction,
spinal anesthesia,
with some intoxications (quinine, chloral hydrate, atropine).

A drop in blood pressure, mostly minimal, is observed in acute infectious diseases as a result of a decrease in the tone of arterioles, which occurs under the influence of toxic inhibition of the vasomotor center, and also due to reduced production of adrenaline by the adrenal glands. The pressure drops even more if the weakness of the heart muscle joins.

Of chronic infectious diseases, tuberculosis, especially pulmonary tuberculosis, is characterized by a drop in blood pressure, both maximum and minimum.

Especially characteristic is the drop in blood pressure for Addison's disease, in which the cause of hypotension is a sharp decrease in adrenal function.

In some people, constantly low blood pressure is established as a result of a violation of higher nervous activity (neurosis) and a change in the nervous regulation of arterial tone as a result. This condition is characterized by certain clinical manifestations (headache, dizziness, general weakness, etc.) and is referred to in the clinic as neurocirculatory (primary) hypotension. Constantly low blood pressure can occur in apparently healthy people, athletes (physiological hypotension).

Known diagnostic value acquires the measurement of blood pressure in certain diseases of the heart. So, in acute myocarditis and with exudative or adhesive pericarditis, a significant decrease in pulse pressure is observed due to a decrease in maximum pressure at a normal or even slightly increased minimum. The first is due to the weakening of the activity of the heart muscle with myocarditis or insufficient diastolic. filling of the ventricles with pericarditis, the second - reflex narrowing of the arterioles.

With a disorder of cardiac activity in persons with heart defects, an increase in the maximum and especially the minimum pressure is sometimes observed (the so-called congestive hypertension). This is due to an increase in the content of CO2 in the blood, and it is known that CO2, acting on the periphery as a vasodilator, excites the vasomotor center and through it causes narrowing of small arteries. If the central action predominates over the peripheral one, then some increase in blood pressure may result, which again decreases with an improvement in the activity of the heart.

Of great diagnostic value is the measurement of blood pressure in aortic valve insufficiency. With this defect, the maximum pressure is either normal or slightly increased, while the minimum is sharply reduced.

Examination of the circulatory organs: