Monitoring blood pressure and heart rate is the most affordable and convenient way to determine the status of the cardiovascular system. And about how to properly measure pressure with a mechanical tonometer, medical workers repeatedly say. However, patients still make mistakes, on the basis of which they make decisions about taking medications.
Sequence of measurement steps
How to properly measure pressure with a mechanical tonometer does not depend on the patient’s emotional mood, conditions and location. This is a set of rules, the violation of which directly affects the result. Before measuring, you need to rest from any load for 10-30 minutes and take a sitting position, stretching your legs forward and relaxing them, straightening your neck.
The cuff is superimposed on the middle third of the forearm on a straight relaxed limb, laid on the table with the palm up. The forearm extends forward so that the ulnar fossa is at the level of the heart. From this moment, the hand should not move anywhere, but lie relaxed in this position.
A stethoscope is put directly on the ears (not on the neck), and a pear is pumped up with a free hand with tracking pulsation on the wrist. After its termination, an additional 20 mmHg is injected and air is vented, a tone is determined that will indicate the level of systolic pressure. As the air is slowly bleeding, tones, that is, pulsation of the brachial artery, will increase and later subside.
The moment of termination of tones is the level of diastolic pressure (DBP). In the case of the phenomenon of infinite tones, the moment of the DBP is taken to be a significant decrease in the 3rd tone, which occurs immediately after the increase in noise that arose after the appearance of the loudest pop — the 1st tone. It is necessary to fulfill all these conditions, since measuring the pressure correctly with a mechanical tonometer means determining the average levels necessary for the selection and monitoring of the treatment regimen.
Cuff discharge limit
Despite the extreme simplicity of the actions performed, a huge number of errors are made when measuring blood pressure by patients. They affect the audibility of tones and the actual determination of pressure, and may cause discomfort when measuring. Most often, patients are mistaken in choosing the upper limit to which the cuff should be inflated.
According to WHO recommendations, it should be determined by the presence of a pulse on the wrist. As soon as the cuff pulsation on the radial artery stopped when the cuff was inflated, another 20 mmHg should be pumped into the cuff, after which the air should be vented and tones determined.
On the question of how to correctly measure pressure with a mechanical tonometer, the photo clearly demonstrates the correct approach. Most patients try to measure on the same principle as electronic devices. They inflate the cuff to high values, which affects the result due to the development of compensatory hypertension with prolonged and excessively strong compression of the large artery.
Pumping up to high values also affects measurement comfort. The patient may have a headache due to developing reflexes, dizziness may develop, shoulder pain and numbness of fingers on the side of compression may appear. These effects should be remembered, because measuring blood pressure with a mechanical tonometer helps to avoid them. And using common and cheap electronic blood pressure monitors, the patient is forced to put up with discomfort when measuring pressure and frequent errors in the development of arrhythmia.
Air bleed rate
The second common mistake made by patients is the high rate of cuff air bleeding. It leads to an incorrect definition of the first tone or its omission. The result is an incorrect determination of systolic pressure and a large difference between the values of adjacent measurements. How to measure the pressure with a mechanical tonometer yourself, at what speed to bleed air from the cuff?
Having pumped it to the level of cessation of pulsation in the radial artery, it is necessary to pump another 20 mmHg. If you can’t hear tones in the stethoscope, you can begin to bleed air. If there are tones, pump air until the pulsation in the stethoscope ceases to be audible and add another 20 mmHg.
Air bleeding should be slow - 3-4 mmHg per second until the first loud tone appears. Do not bleed air at a speed faster than 5 mmHg, as this can introduce an error of 10-15%. Given that the heart rate is more than 1 time per second, the minimum error at high speed is 5 mmHg, and the maximum, especially with an irregular heartbeat or bradycardia, is 20 mmHg.
This is the explanation why many people have too much variation between the measurement results. In addition, the high rate of air bleeding leads to another mistake that patients love - to blame the high value of diastolic pressure due to missing the last tone at a high rate of air discharge from the cuff.
Other errors
Without the control of the health worker, the patient is prone to arbitrariness and some sort of experimentation, some of which are designed to refute one or another doctor’s recommendation. And the patient was repeatedly explained how to correctly measure the pressure with a mechanical tonometer to himself. But it is precisely without the control of the doctor and proper discipline at home that he is inclined to do as he is comfortable, or as he is used to, even if it is wrong. This is confirmed by the following list of measurement errors, which are extremely common.
Preparation
The first mistake is the lack of preparation for measuring pressure. Forgetting the main recommendation on how to correctly measure blood pressure with a mechanical blood pressure monitor, patients often use devices, including electronic ones, without resting from the previous load. The correct pressure value will be that which was measured at rest or after 10-30 minutes of rest after the cessation of physical activity. And immediately after its termination, the pressure indicators will be 20-30% higher than the average for this patient.
Hand movements
The second mistake is anxiety and hand movements when measuring pressure. Moving your shoulder or turning your forearm is prohibited when measuring pressure. The arm should lie on the table in a relaxed position, palm up, and the cuff is located at heart level. The head of the stethoscope on the lower border of the cuff. In this case, you can not pump up the arm with the cuff attached, which is why tonometers are better suited for independent measurement, in which the stethoscope is built into the cuff or does not require holding.
Awkward posture
The third mistake is the conscious or unintentional squeezing of large arteries. In the protocol of the Ministry of Health, where the rules are written on how to correctly measure pressure with a mechanical tonometer, there are a number of requirements. It is indicated that the patient should sit relaxed, leaning slightly back, and look in front of him. Feet should also be relaxed, stretched out in front of you, not crossed. In this position, crushing of the vertebral and femoral arteries is excluded, which increases the value of mainly diastolic pressure. It is necessary to comply with these requirements, otherwise the patient will often see inadequate pressure figures.