Blood pressure measurement
Measurement of arterial( blood pressure) belongs to the category of those very important diagnostic methods of examination, the skills of which should be for every civilized person.
Violation of blood pressure can be a symptom of serious diseases, timely diagnosis of which is able to provide at the current level of medical development or complete cure of patients, or reliably stop the progression of the pathological process, prolong the patient's life, prevent severe disorders and disability. This makes it necessary to consider the method of measuring blood pressure as a pre-medical procedure, which, if necessary, should be carried out directly at home. Therefore, in every family where there are patients with hypertensive disease or suffering from other blood pressure disorders, it is advisable to have a device for measuring blood pressure and be able to use it.
The blood pressure measurement is performed by special devices - sphygmomanometers, the main parts of which are a rubber cuff( for clamping the artery), a pump or a balloon( for air injection) and a mercury or spring pressure gauge( for pressure measurement).Read here how to choose the optimal tonometer for a home. In everyday practice, measurement of blood pressure is made in the brachial artery by a conventional tonometer according to the auditory method of NS.Korotkova using a stethophonendoscope.
The
Stethoscopescope The principle of measuring blood pressure by this method is as follows. On the shoulder( between the shoulder and elbow joints) is put a hollow rubber cuff in which the air is pumped up to the disappearance of the pulse on the radial artery( determined 2-3 cm above the wrist joint along the inside of the forearm), i.e., until the moment when the pressurein the cuff will exceed the pressure in the brachial artery. With the gradual release of air from the cuff and listening at the same time to the artery below the cuff, the first appearance of tones indicates that the pressure in the cuff is equal to the systolic( at the time of contraction of the heart) pressure in the brachial artery and blood during cardiac contraction begins to flow through the compressed artery. In the future, a sharp weakening( or disappearance) of the tones shows that the artery became passable during cardiac relaxation( diastole), that is, the pressure in the cuff is equal to the diastolic pressure in the artery.
The device consists of: a) from the fields of a rubber cuff in the width of 12 to 14 cm, which is inserted into the cover of inelastic matter;on it are fastened fasteners or other devices for fixing the cuff on the forearm;b) a mercury or spring pressure gauge with a scale of up to 300 mm or higher;c) from the air-injecting cylinder. All three main parts are connected to the common system by rubber tubes using a T-shaped plastic or metal tube. To release excess air around the cylinder there is a tap. Arterial pressure is measured when the following rules are observed.
1. The room should be warm enough.
2. The patient sits or lies on his back on the couch or bed and rests for 10-15 minutes. During the measurement of pressure the patient should lie or sit perfectly calmly, do not talk and do not follow the measurement. It should be borne in mind that in a recumbent position, blood pressure is usually 5-10 mm lower than in a sitting one.
3. From the cuff carefully evacuate the rest of the air;impose it tightly, but not tightening, on the shoulder, so that the lower edge of the cuff is a few centimeters above the elbow, and fastened to buckles, Velcro or hooks;the hand should be completely naked, turned palm up, conveniently located at the heart level;the sleeve of the shirt, if not removed, should not press on the hand;musculature should be relaxed.
4. To the ulnar fovea is attached tightly, but without pressure stethoscope - it is best to use a bicuspid with rubber or polyvinylchloride tubes.
5. With complete silence in the room, the balloon( "pear") starts to gradually inject air into the cuff, the pressure in which is recorded by a manometer.
6. The injection is performed until the tones or noises appear in the ulnar artery and then the pressure in the cuff is raised by another 30 mm.
7. The injection is then stopped. Slowly open the small cock at the cylinder. At the same time, the air starts to leave gradually.
8. Note the height of the mercury column at which the first clear noise is heard. At this point, the air pressure in the cuff and pressure gauge becomes slightly less than the maximum pressure in the artery, so that the blood wave can get into the peripheral section of the vessel and cause a tone.
The digit indicated on the scale of the manometer and is taken as the maximum( systolic) pressure indicator.
9. With further reduction of air pressure in the cuff, usually after the phase of tones in the artery, noises appear and then tones again. These "final" tones are gradually amplified, becoming more and more sonorous and then suddenly and sharply weaken and quickly stop.
The minimum( diastolic) pressure corresponds to the disappearance of tones.
10. By subtracting the maximum pressure from the obtained digit, the minimum pressure digits receive the value of the pulse pressure amplitude( pulse pressure), which is an important criterion for evaluating the cardiovascular system.
11. Due to some mental excitement, and perhaps even a direct mechanical stimulation of the nervous network of the blood vessels, the arterial pressure in the first measurement in most cases is slightly higher than in the subsequent measurements. Therefore, the measurement is necessarily repeated without removing the cuff from which the air is completely discharged, 1-2 times at intervals of several minutes, and taking the smallest values as arterial pressure indicators.
12. Often the arterial pressure, measured separately on the left and right hand, is not the same and differs by 10,15, and in some cases by 20 mm. Therefore, a consistent measurement of blood pressure is performed on both hands and the arithmetic mean is calculated.
Significant quantitative differences( more than 40-50 mm) of arterial pressure on different arms are evidence of serious pathological disorders and require immediate consultation of the patient with the therapist.
13. Repeated blood pressure measurements are necessary. In patients with unstable blood pressure, it is advisable to measure it several times a day to catch the influence of sleep, food, rest and work.
14. The figures obtained in the measurement of blood pressure are usually written in the form of a fraction, in which the numerator corresponds to the systolic pressure, and the denominator to the diastolic.
Distinguish:
• systolic( maximum) pressure;
• diastolic( minimal);
• pulse pressure.
Arterial pressure ( AD) is the pressure that blood exerts on the walls of arteries, and depends primarily on the strength of the cardiac contractions( cardiac output) and the tone of the arterial wall.
Systolic pressure is the pressure during the heart systole, when it reaches the greatest value during the cardiac cycle. Diastolic pressure is the pressure toward the end of the diastole of the heart, when it reaches the minimum value during the cardiac cycle( during rest period).The systolic pressure reflects the work of the heart, the diastolic pressure is the state( magnitude) of the tone of the peripheral vessels.
The difference between systolic and diastolic pressure is called pulse pressure.
Arterial pressure is most often determined by the auscultative method suggested by NS.Korotkovym( from the Latin auscultatio - "listening").To do this, use special devices - tonometers. The tonometer consists of a cuff with textile fasteners, a rubber pear and a manometer( mercury or membrane).Recently, electronic pressure gauges have been widely used.
Measurement is carried out in the position of the patient lying down or sitting after a 10- to 15-minute rest. The amount of blood pressure is determined in millimeters of mercury.
Procedure:
1. Apply the cuff over the naked shoulder of the patient 2-3 cm above the elbow fold. Clothes should not squeeze the shoulder above the cuff. Secure the cuff so that only one finger passes between it and the shoulder.
2. Place the patient's arm in the unfolded position with the palm facing up, the muscles should be relaxed. If the patient is sitting, then for a better extension of the limb, ask him to put a hand, compressed into a fist, under the elbow.
3. Connect the manometer to the cuff. Check the position of the manometer needle relative to the zero mark.
4. To feel the pulse on the brachial artery in the region of the ulnar fossa and put a phonendoscope on this place.
5. Close the valve on the pear and pump air into the cuff. The air must be pumped until the pressure in the cuff, according to the gauge readings, exceeds approximately 30 mm Hg. Art.the level at which the pulsation of the radial artery ceases to be determined.
6. Open the valve and let the air out of the cuff slowly, at a speed of no more than 20 mm Hg. At the same time, listen to the phonendoscope on the tones on the brachial artery and follow the indicators of the scale of the manometer.
7. When the first sounds( called Korotkov tones) appear above the brachial artery, note the level of systolic pressure.
8. At the moment of sharp weakening or complete disappearance of tones on the brachial artery, note the magnitude of diastolic pressure.
9. The blood pressure measurement data, rounded to 0 or 5, should be recorded as a fraction: in the numerator - systolic pressure, in the denominator - diastolic pressure. For example: 120/75 mm Hg. Art. In addition to digital recording of blood pressure in the form of a fraction, the measurement data are recorded in a temperature sheet in the form of a column, the upper limit of which means systolic, and the lower one - diastolic pressure.
Measure arterial pressure usually 2-3 times at intervals of 1-2 minutes, while the air from the cuff should be completely discharged.
It should be borne in mind that in some cases in the interval between systolic and diastolic pressure the intensity of the tones begins to weaken, sometimes significantly. This point can be mistaken for very high diastolic pressure. If you continue to release air from the cuff, then the volume of the tones will increase, and they will break at the level of the true diastolic pressure. If the pressure in the cuff is raised only to the level of "intermediate attenuation of tones," one can make a mistake in determining the systolic pressure. In order to avoid mistakes in blood pressure measurement, the pressure in the cuff should be raised sufficiently high, with a "reserve", and letting air out, continue listening to the total pressure drop in the cuff to zero.
Another error is possible. With a strong pressure of the phonendoscope on the brachial artery, tones in some patients are heard to zero. In these cases, the head of the phonendoscope should not be pressed against the artery, and the diastolic pressure should be noted but the sharp decrease in the intensity of the tones.
Normal blood pressure is between 140/90 and 100/60 mm Hg. Art. With age, blood pressure slightly increases. Physical stress, emotional excitement cause an increase in blood pressure. There are also daily fluctuations - in the morning the pressure is lower, in the evening - higher, during sleep the pressure is the lowest. After eating, the systolic pressure rises.