Measurement of pressure

Measurement of arterial pressure - an important diagnostic method of inspection. Measurement of arterial pressure is considered by physicians as the main pre-medical procedure which to carry out, as required, important to be able independently at home.

The device for measurement of pressure

For these purposes the special device for measurement of pressure, the called tonometer is used. It consists of such elements:

• Sphygmomanometer;
• Manometer.

The main parts of the sphygmomanometer are a rubber cuff for crossclamping of an artery and a cylinder (pump) for air forcing. Manometers happen spring and mercury.

Usually, tonometers with use of a stetofonendoskop (a stethoscope, a phonendoscope) are applied to measurement of arterial pressure. Measurement is performed by an acoustical method of Korotkov.

Basic rules of measurement of arterial pressure

Arterial pressure needs to be measured, following the following rules:

1. It has to be indoors warm;

2. The patient has to sit or lie conveniently on spin. Before measurement of pressure of people has to have a rest within 10 – 15 minutes. It should be noted that in lying situation pressure, usually, is put 5 - 10 mm lower, than at its measurement in a sitting position;

3. Directly during measurement of arterial pressure the patient has to observe tranquility: not to talk and not to look at the device for measurement of pressure;

4. The hand of the patient has to be absolutely naked, the palm has to look up and conveniently be located at the level of heart. The raised sleeve of clothes should not press on veins. Muscles of the patient have to be absolutely relaxed;

5. From a device cuff for measurement of pressure carefully expel the air rest;

6. Densely impose a cuff on a hand, at the same time, without pulling together it strongly. The bottom edge of a cuff has to be located 2 - 3 cm above a bend in an elbow. Then the cuff is tightened or connected a flypaper;

7. The stethoscope, densely, but without pressure is put to an internal dimple on an elbow. It is the best of all if it is with 2 ears and rubber (polyvinyl chloride) tubes;

8. In complete silence, by means of a device cylinder for measurement of pressure, gradually force air in a cuff, at the same time, pressure in it is registered the manometer;

9. Air is forced until tones or noise in an elbow artery tones then raise pressure in a cuff approximately by 30 mm a little stop;

10. Now forcing of air is stopped. Slowly the small crane at a cylinder opens. Air begins to come out gradually;

11. Height of a mercury column (value of upper pressure) with which clear noise is for the first time heard is fixed. At this moment air pressure in the device for measurement of pressure decreases in comparison with pressure level in an artery in this connection the wave of blood can get into a vessel. Thanks to it tone (on a sound she reminds a loud pulsation, heart beat) is also caused. This size of upper pressure, the first indicator, is an indicator of the maximal (systolic) pressure;

12. In process of further pressure decrease of air in a cuff, there are not clear noise, and then tones are again listened. These tones gradually amplify, then become clearer and sonorous, but then suddenly weaken and completely stop. Disappearance of tones (heart beat sounds) testifies to an indicator of the minimal (diastolic) pressure;

13. The additional indicator revealed when using methods of measurement of pressure - the size of pulse amplitude of pressure or pulse pressure. This indicator is estimated by subtraction from the maximum size (systolic pressure) minimum (diastolic pressure). Pulse pressure – important criterion for assessment of a condition of cardiovascular system of the person;

14. The indicators received using methods of measurement of pressure register in the form of the fraction divided by inclined line. The upper figure means the size of systolic pressure, lower – diastolic.

Features of measurement of pressure

At measurement of arterial pressure several times in a row, it is necessary to pay attention to some features of an organism. So, values of indicators at the subsequent measurement are, as a rule, slightly lower, than at the first measurement. Exceeding of indicators at the first measurement can be caused by the following reasons:

• Some hyperphrenia;
• Mechanical irritation of nervous network of vessels of blood.

In this regard, measurement of arterial pressure is recommended to repeat, without removing at the same time a cuff from a hand after the first measurement. Thus, having applied methods of measurement of pressure several times as the result is fixed by average values.

Pressure in the right and left hand often are various. Its size can differ on 10 – 20 mm. Therefore, physicians recommend to apply methods of measurement of pressure on both hands, and to fix average sizes. Measurement of arterial pressure is performed consistently on the right and left hands, several times, and the received sizes then use for calculation of an arithmetic average of an indicator. For this purpose, sizes of each indicator (separately upper pressure and separately lower) are put and divided into that number of times how many measurement was performed.

If at the person unstable arterial pressure is observed, measurement needs to be performed regularly. Thus, it is possible to catch communication of changes in its level in connection with influence of various factors (a dream, overfatigue, food, work, rest). All this needs to be considered at use of methods of measurement of pressure.

Normal amounts, when using any method of measurement of pressure, are pressure indicators at the level of 100/60 - 140/90 mm of mercury.

Possible mistakes

It must be kept in mind that sometimes between upper and lower pressure intensity of tones can weaken, times considerably. And then this moment can be taken for too high pressure by mistake. If to continue to let out the air from the device for measurement of pressure, the loudness of tones increases, and they will stop at the level of the real lower (diastolic) pressure. If pressure in a cuff is insufficiently lifted, it is possible to be mistaken in value of systolic pressure easily. So, not to make a mistake, it is necessary to use methods of measurement of pressure correctly: to raise pressure level in a cuff rather highly that "pressed", and here letting out the air, it is necessary to continue to listen to tones before full pressure drop to zero.

Also one more mistake is possible. If strongly to press a phonendoscope a humeral artery, at some people tones are listened to zero. Therefore, it is not necessary to press a phonendoscope head directly on an artery, and value of the lower, diastolic pressure, it is necessary to record on sharp decrease in intensity of tones.