Measurement and evaluation of blood pressure in children

Arterial pressure is usually measured with a sphygmomanometer (mercury or aneroid) and a phonendoscope (stethoscope). The scale of the sphygmomanometer scale (mercury or aneroid) should be 2 mm Hg. The mercury manometer reading is evaluated on the upper edge (meniscus) of the mercury column. The determination of blood pressure using a mercury manometer is considered a "gold standard" among all methods of measuring blood pressure using other devices, since it is the most accurate and reliable.

Measurement of blood pressure is carried out no earlier than 1 hour after eating, drinking coffee, stopping physical activity, smoking, staying in the cold. The procedure of measurement should be explained to the patient in order to avoid a protective reaction on his part, which may cause an increase in blood pressure. During the measurement, the patient should sit, resting on the back of the chair, with relaxed, not crossed legs, do not change position and do not talk during the entire procedure of measuring blood pressure. It is necessary to choose the correct cuff corresponding to the circumference of the patient's shoulder - a child, a teenager or an adult. The width of the inner (rubber) chamber of the cuff should be at least. 40% of the circumference of the shoulder, the length of the rubber cuff should cover from 80 to 100% of the circumference of the shoulder. The circumference of the shoulder is measured with a centimeter tape with an accuracy of 0.5 cm at the midpoint of the distance between the elbow and the acromial process of the scapula. The cuff is placed so that the center of the rubber chamber is located above the brachial artery on the inner surface of the shoulder, and the lower edge of the cuff is 2.0-2.5 cm above the elbow fold. The density of the cuff overlap must be such that one finger can be held between the cuff and the shoulder surface of the patient.

Recommended cuff width for children, according to WHO

	Age	Cuff dimensions, cm
Less than 1 year		2.5
1-3 years		5-6
4-7 lay down		8-8.5
8-9 years		9
10-13 years old		10
14-17 years old		13

The injection of air into the cuff to the maximum level (by 30 mm Hg above the level of the SBP, assessed palpation) must be done quickly. Slow air injection into the cuff leads to a violation of venous outflow, increased pain and "blurring" the sound. The air from the cuff is released at a rate of 2 mm Hg drop in the mercury column. Per second, and with the appearance of Korotkov's tones - 2 mm Hg. For each beat of the pulse. If the meniscus of the mercury column at the moment of appearance or disappearance of Korotkov's tones is between two divisions of the pressure gauge scale, the SBP or DBP readings are evaluated at the nearest upper value. In case of poor hearing, you should quickly release air from the cuff, check the position of the stethoscope and repeat the procedure in 2-3 minutes. Knowing the distinctive features of the different phases of Korotkov's tones allows you to determine the level of SBP and DBP most accurately. The accuracy of determining blood pressure also depends on the speed of decompression: the higher the speed, the lower the accuracy of the measurement.

Characteristics of Korotkov's tones by phases

Phase	Characteristics of Korotkov's tones
I (K1)	Sounds weak, tapping with gradually increasing intensity
II (KII)	The sounds are softer and longer, muffled, buzzing
III (KIII)	The sounds again become distinct and loud
IV (KIV)	Sounds soft, muffled, less distinguishable
V (KV)	Complete disappearance of sounds

The SBA level is determined from the beginning of the first phase of Korotkov's tones - according to the first of a series of successive tones, i.e. For the first tone must follow the second. A single tone at the beginning of the phase (when the first tone is followed by silence - auscultative failure) is ignored.

The DB value is determined from the beginning of the V phase of Korotkov's tones - by the silence following the last tone of the IV phase. The last tone at the end of the phase, even if it is single (when the last tone is preceded by an auscultatory failure) is always taken into account. Auscultation should be continued for 20 mm after the disappearance of the last tone, and with a DBP above 90 mm Hg. - over 40 mm. This is due to the fact that after an auscultative failure, tones can resume. Compliance with this rule will avoid the definition of a falsely elevated DBP.

Absence of the V phase, i.e. When Korotkov's tones are heard until the end of the drop in the mercury column ("the phenomenon of infinite tone"), can be observed with a high cardiac output (in children, patients with thyrotoxicosis, fever, aortic insufficiency, pregnant). In these cases, the level of DBP is estimated at the beginning of the IV phase - according to the first of a series of consecutive quieting Korotkov tones.

Diagnosis of arterial hypertension in children and adolescents is carried out using special tables based on the results of population studies. Diagnostics consists of the following stages:

• the definition according to the special tables of the percentile of growth corresponding to the patient's sex and age;
• calculation of mean values of SBP and DBP on the basis of three blood pressure measurements conducted with an interval of 2-3 min;
• comparison of mean values of SBP and DBP of the patient, obtained from the results of three-dimensional measurement of blood pressure at one visit, with 90th and 95th percentiles of blood pressure corresponding to the sex, age and percentile of the patient's growth;
• a comparison of mean values of SBP and DBP recorded at the patient at three visits with an interval between visits of 10-14 days, with 90th and 95th percentiles of blood pressure corresponding to the sex, age and percentile of the patient's growth.

Normal blood pressure is considered when the average levels of SBP and DBP at three visits do not exceed the values of the 90th percentile for a given age, gender and height.

High normal blood pressure - when the mean levels of SBP and / or DBP at three visits are equal to or exceed the values of the 90th percentile, but less than the 95th percentile for a given age, gender and height.

Arterial hypertension - when the average levels of SBP and / or DBP are at three visits equal to or higher than the 95th percentile for a given age, gender and growth.

[1], [2], [3], [4], [5], [6], [7], [8], [9], [10]