Blood pressure, its types. The maximum arterial blood pressure occurs in the aorta Relationship between high blood pressure and vascular conditions
Blood (arterial) pressure is the pressure of the blood on the walls of the blood (arterial) vessels of the body. Measured in mm Hg. Art. In different parts of the vascular bed, blood pressure is not the same: in the arterial system it is higher, in the venous system it is lower. So, for example, in the aorta, the blood pressure is 130-140 mm Hg. Art., in the pulmonary trunk - 20-30 mm Hg. Art., in the large arteries of the great circle - 120-130 mm Hg. Art., in small arteries and arterioles - 60-70 mm Hg. Art., in the arterial and venous ends of the capillaries of the body - 30 and 15 mm Hg. Art., in small veins - 10-20 mm Hg. Art., and in large veins it can even be negative, i.e. at 2-5 mm Hg. Art. below atmospheric. The sharp decrease in blood pressure in the arteries and capillaries is due to the large resistance; the cross section of all capillaries is 3200 cm2, the length is about 100,000 km, while the cross section of the aorta is 8 cm2 with a length of several centimeters.
The amount of blood pressure depends on three main factors:
1) frequency and strength of heart contractions;
2) the magnitude of the peripheral resistance, i.e. tone of the walls of blood vessels, mainly arterioles and capillaries;
3) volume of circulating blood.
There are systolic, diastolic, pulse and average dynamic pressure.
Systolic (maximum) pressure is the pressure reflecting the state of the myocardium of the left ventricle. It is 100-130 mm Hg. Art. Diastolic (minimum) pressure- pressure characterizing the degree of tone of the arterial walls. Equal to an average of 60-80 mm Hg. Art. Pulse pressure is the difference between systolic and diastolic pressure. Pulse pressure is necessary to open the semilunar valves of the aorta and pulmonary trunk during ventricular systole. Equal to 35-55 mm Hg. Art. The average dynamic pressure is the sum of the minimum and one third of the pulse pressure. It expresses the energy of the continuous movement of blood and is a constant value for a given vessel and organism.
BP can be measured by two methods: direct and indirect. When measuring by a direct, or bloody, method, a glass cannula or needle is inserted into the central end of the artery and fixed, which is connected to the measuring device with a rubber tube. In this way, blood pressure is recorded during major operations, for example, on the heart, when constant monitoring of pressure is necessary. In medical practice, blood pressure is usually measured by an indirect, or indirect (sound) method.
N.S. Korotkov (1905) using a tonometer (mercury sphygmomanometer D. Riva-Rocci, membrane blood pressure meter for general use, etc.).
The value of blood pressure is influenced by various factors: age, body position, time of day, place of measurement (right or left hand), body condition, physical and emotional stress, etc. There are no universally accepted standards for blood pressure for people of different ages, although it is known that with age in healthy individuals, blood pressure rises slightly. However, back in the 1960s, Z.M. Volynsky and his staff, as a result of a survey of 109 thousand people of all age groups, established these standards, which have received wide recognition in our country and abroad. Normal blood pressure values should be considered:
maximum - at the age of 18-90 years in the range from 90 to 150 mm Hg. Art., and up to 45 years - no more than 140 mm Hg. Art.;
the minimum - at the same age (18-90 years) in the range from 50 to 95 mm Hg. Art., and up to 50 years - no more than 90 mm Hg. Art.
The upper limit of normal blood pressure before the age of 50 is 140/90 mm Hg. Art., aged over 50 years - 150/95 mm Hg. Art.
The lower limit of normal blood pressure at the age of 25 to 50 years is a pressure of 90/55 mm Hg. Art., up to 25 years - 90/50 mm Hg. Art., over 55 years - 95/60 mm Hg. Art.
To calculate the ideal (proper) blood pressure in a healthy person of any age, the following formula can be used:
Systolic blood pressure = 102 + 0.6 x age;
Diastolic blood pressure = 63 + 0.4 x age.
An increase in blood pressure above normal values is called hypertension, a decrease is called hypotension. Persistent hypertension and hypotension may indicate pathology and the need for medical examination.
6. Arterial pulse, its origin, places where the pulse can be felt
arterial pulse called the rhythmic fluctuations of the arterial wall, due to the systolic increase in pressure in it. The pulsation of the arteries is determined by lightly pressing it against the underlying bone, most often in the region of the lower third of the forearm. The pulse is characterized by the following main features:
1) frequency - the number of beats per minute;
2) rhythm - the correct alternation of pulse beats;
3) filling - the degree of change in the volume of the artery, set by the strength of the pulse beat;
4) tension - is characterized by the force that must be applied to squeeze the artery until the pulse disappears completely.
A pulse wave occurs in the aorta at the moment of expulsion of blood from the left ventricle, when the pressure in the aorta rises and its wall stretches. The wave of increased pressure and the oscillations of the arterial wall caused by this stretching propagate at a speed of 5-7 m/s from the aorta to arterioles and capillaries, exceeding the linear velocity of blood movement by 10-15 times (0.25-0.5 m/s).
The pulse curve recorded on a paper tape or film is called a sphygmogram. On the sphygmogram of the aorta and large arteries, there are:
1) anacrotic rise (anacrota) - due to a systolic increase in pressure and stretching of the arterial wall caused by
this rise;
2) catacrotic descent (katacrotus) - due to a drop in pressure in the ventricle at the end of systole;
3) incizuru - a deep notch - appears at the time of ventricular diastole;
4) dicrotic rise - a secondary wave of increased pressure as a result of the repulsion of blood from the semilunar valves of the aorta.
The pulse can be felt in those places where the artery is close to the bone. Such places are: for the radial artery - the lower third of the anterior surface of the forearm; - inguinal region, for the dorsal artery of the foot - the dorsum of the foot, etc. The pulse has a great diagnostic value in medicine. So, for example, an experienced doctor, pressing on the artery until the pulsation stops completely, can quite accurately determine the value of blood pressure. In diseases of the heart, various types of rhythm disturbances - arrhythmias - can be observed. With thromboangiitis obliterans ("intermittent claudication"), there may be a complete absence of pulsation of the dorsal artery of the foot, etc.
Blood Pressure- blood pressure on the walls of the main arteries. The pressure is highest during systole, when the ventricles contract (systolic pressure), and lowest during diastole, when the ventricles relax and... medical terms
Pressure (blood)- Blood pressure is the pressure that blood exerts on the walls of blood vessels, or, in other words, the excess pressure of the fluid in the circulatory system over atmospheric pressure. The most commonly measured blood pressure; besides him, allocate ... ... Wikipedia
BLOOD PRESSURE- (blood pressure) blood pressure on the walls of the main arteries. The pressure is highest during systole, when the ventricles contract (systolic pressure), and lowest during diastole, when... ... Explanatory Dictionary of Medicine
Blood pressure- I Blood pressure Blood pressure blood pressure on the walls of blood vessels and chambers of the heart; the most important energy parameter of the circulatory system, which ensures the continuity of blood flow in the blood vessels, diffusion of gases and filtration ... Medical Encyclopedia
BLOOD PRESSURE- BLOOD PRESSURE, the pressure that blood exerts on the walls of blood vessels (the so-called lateral blood pressure) and on that column of blood that fills the vessel (the so-called end blood pressure). Depending on the vessel, K. d is measured in krom ... ... Big Medical Encyclopedia
BLOOD PRESSURE- blood pressure, hydrodynamic pressure of blood in the vessels, due to the contraction of the heart, the resistance of the vessel walls and hydrostatic forces. K. d. is not the same in different parts of the vascular system and serves as one of the indicators ... ... Veterinary Encyclopedic Dictionary
Blood pressure- Blood pressure is the pressure that blood exerts on the walls of blood vessels, or, in other words, the excess pressure of the fluid in the circulatory system over atmospheric pressure, one of the important signs of life. Most often under this concept ... ... Wikipedia
blood pressure- hydrodynamic pressure of blood in the vessels, due to the work of the heart and the resistance of the walls of the vessels. Decreases with distance from the heart (greatest in the aorta, much lower in the capillaries, least in the veins). Normal for an adult ... ... encyclopedic Dictionary
Arterial pressure- I Blood pressure is the pressure of the blood on the walls of the arteries. The blood pressure in the blood vessels decreases as they move away from the heart. So, in adults in the aorta, it is 140/90 mm Hg. Art. (the first number indicates systolic, or upper ... Medical Encyclopedia
BLOOD PRESSURE- blood pressure on the walls of blood vessels and chambers of the heart, resulting from the contraction of the heart, pumping blood into the vascular system, and vascular resistance; ensures the continuity of blood flow in the blood vessels. K. d. is located ... Biological encyclopedic dictionary
Answer from Danil Strubin[guru]
What atmospheres? It would break into pieces. Measure with a tonometer..
Answer from 2 answers[guru]
Hello! Here is a selection of topics with answers to your question: What is the pressure in the aorta?
Answer from Super Mobi Club[guru]
The maximum systolic pressure is normal - 120–145 mm Hg.
End-diastolic pressure - 70 mm Hg.
Answer from Mechs[guru]
that is - 1/5-1/6 of the atmosphere :))
Answer from AO[guru]
Well, it's already been answered here.
Answer from Foxius[guru]
The magnitude of blood pressure is mainly determined by two conditions: the energy that is reported to the blood by the heart, and the resistance of the arterial vascular system, which has to be overcome by the flow of blood flowing from the aorta.
Thus, the value of blood pressure will be different in different parts of the vascular system. The greatest pressure will be in the aorta and large arteries, in small arteries, capillaries and veins it gradually decreases, in the vena cava the blood pressure is less than atmospheric pressure. The blood pressure will also be different throughout the cardiac cycle - it will be greater at the moment of systole and less at the moment of diastole. Fluctuations in blood pressure during systole and diastole of the heart occurs only in the aorta and arteries. In arterioles and veins, blood pressure is constant throughout the cardiac cycle.
The greatest pressure in the arteries is called systolic, or maximum, the smallest - diastolic, or minimum.
The pressure in different arteries is not the same. It can be different even in arteries with the same diameter (for example, in the right and left brachial arteries). In most people, the value of blood pressure is not the same in the vessels of the upper and lower extremities (usually the pressure in the femoral artery and arteries of the lower leg is greater than in the brachial artery), which is due to differences in the functional state of the vascular walls.
At rest in healthy adults, systolic pressure in the brachial artery, where it is usually measured, is 100-140 mm Hg. Art. (1.3-1.8 atm) In young people, it should not exceed 120-125 mm Hg. Art. Diastolic pressure is 60-80 mm Hg. Art. , and is usually 10 mm higher than half the systolic pressure. A condition in which blood pressure is low (systolic below 100 mm) is called hypotension. A persistent increase in systolic (above 140 mm) and diastolic pressure is called hypertension. The difference between systolic and diastolic pressure is called pulse pressure, usually it is 50 mm Hg. Art.
Blood pressure in children is lower than in adults; in older people, due to a change in the elasticity of the walls of blood vessels, it is higher than in young people. Blood pressure in the same person is not constant. It changes even during the day, for example, it increases when eating, during emotional manifestations, during physical work.
Human blood pressure is usually measured in an indirect way, which was proposed by Riva-Rocci at the end of the 19th century. It is based on determining the amount of pressure required to completely compress an artery and stop blood flow in it. To do this, a cuff is placed on the limb of the subject, connected to a rubber pear, which serves to pump air, and a pressure gauge. When air is forced into the cuff, the artery is squeezed. At the moment when the pressure in the cuff becomes higher than the systolic one, the pulsation at the peripheral end of the artery stops. The appearance of the first pulse impulse when the pressure in the cuff decreases corresponds to the value of the systolic pressure in the artery. With a further decrease in pressure in the cuff, the sounds first increase and then disappear. The disappearance of sounds characterizes the magnitude of diastolic pressure.
The time during which the pressure is measured should not exceed 1 min. , as blood circulation below the cuff application site may be impaired.
In most cases, the clinic uses either the Riva-Rocci apparatus or a tonometer (the only difference is in the manometer - mercury or mechanical). But at home, devices of modern design (usually automatic) are usually used.
However, there are a number of nuances in the interpretation of the measurement results. It is clear that with age, as well as with the occurrence of a number of diseases, the mechanisms of regulation of blood pressure are violated. But we do not think about the issue of the emergence of a relationship between upper and lower pressure.
However, it is worth considering the reasons for the change in the upper and lower pressures separately. Understanding these reasons can make it possible to act in the right direction.
Arterial pressure
The characteristics of blood pressure are two important quantities - upper and lower pressure:
- Upper pressure (systolic).
- Lower pressure (diastolic).
Cardiac cycle
The entire cardiac cycle in a healthy person takes about 1 second. Stroke volume is approximately 60 ml of blood - this is the amount of blood that an adult heart expels in one systole, and approximately 4 liters of blood is pumped by the heart in a minute.
The process of ejection of blood into the ventricles during atrial contraction is called systole. At this time, while the atria are contracting, the ventricles are resting - they are in diastole.
Remembering your visit to the therapist, remember the sensations that come at the moment you start to release air from the tonometer cuff - at some point, pulsations begin. Actually, this device was also called a tonometer for the reason that the doctor listens to the tone (for us, these are pulsations) and measures the number of clicks (Korotkov's tones).
The first blow that the doctor hears (and we feel it as the beginning of pulsations), and the numerical value is recorded by the pressure gauge for this moment, is called the upper pressure, systolic. It corresponds to the systole of the ventricles, which, in comparison with the atria, carry a much greater load. Therefore, the weight of the ventricles is greater, since it is they who pump blood through two circles of blood circulation.
If we briefly characterize the cardiac cycle (the sequence of work of the atria and ventricles), then it looks like this:
- Atrial systole - ventricular diastole.
- Ventricular systole - atrial diastole.
That is, when we talk about systole, we mean exactly ventricular systole (the ventricle works - it pushes blood), and when we talk about diastole, we mean ventricular diastole (the ventricle rests).
Coordinated and well-coordinated work of the heart and all its 4 chambers allows each other to rest. This is achieved by the fact that during the work of the atria the ventricles of the heart rest, and vice versa.
If you specify the stages of such a process in turn, it will look like this:
- From the whole body, venous blood through the systemic circulation enters the right atrium.
So the heart ensures the promotion of blood rich in various nutrients for cells and oxygen through the systemic and pulmonary circulation.
Pressure rises and falls
In the case of hypertension, the blood puts pressure on the walls of blood vessels above normal. Vessels, in turn, resist the flow of blood. In this case, both upper and lower pressure can increase. This resistance depends on a number of reasons:
- Preservation of the lumen (patency) of the vessels. The higher the tone of the vessel, the lower the capacity of the blood.
- The length of the bloodstream.
- Blood viscosity.
Here, according to the laws of physics, everything is explained very simply - the smaller the lumen of the vessel, the more it will resist the advancing blood. The same will happen with an increase in blood viscosity.
In the practice of cardiologists, such a phenomenon as arterial hypotension is quite common - a decrease in pressure below 90/60 mm Hg. From the presented figures it is clear that in this case there is a decrease in the upper and lower pressure.
Low lower pressure can be within 50 mm Hg. Art. and below. This is a dangerous situation and requires the provision of emergency medical care, since with a diastolic pressure of 40 mm Hg. Art. Severely reversible and poorly controlled processes develop in the human body.
Top pressure
If any arterial vessels do not have time to adapt and expand to the desired caliber in a timely manner, or there is an obstacle in the way of blood flow (atherosclerotic plaque), then the outcome of this will be increased systolic pressure.
There are a number of parameters on which the upper pressure indicator directly depends:
- Force of contraction of the heart muscle.
- The tone of the blood vessels and their resistance.
- Heart rate in a certain period of time.
Optimal systolic pressure mm Hg. Art. But, for example, when classifying arterial hypertension, there is a certain scale at which the indicator is 139 mm Hg. Art. classified as normal high. This is already a harbinger of hypertension.
Even in a healthy person, systolic pressure can fluctuate during the day, which can be caused by:
- Alcohol.
- Smoking.
- Reception of a large amount of salty food, coffee, tea.
- mental overload.
Upper pressure increase
There are also pathological causes that lead to an increase in upper pressure:
- Kidney pathology.
- Heredity.
- Vascular spasm.
- Changes in the hormonal background of any origin.
- Overweight.
- Excessive fluid and/or salt intake.
- Atherosclerosis.
- Aortic valve lesions.
- Age features and changes.
Patients suffering from persistent arterial hypertension with predominant rises in upper pressure, even without measuring it, know that it is elevated, as they experience such symptoms:
- Headache, most often in the occipital region.
- Vertigo.
- Nausea.
- Labored breathing.
- Flashing flies before the eyes, blurred vision.
Upper pressure reduction
- Physical exercise.
- Change in climatic conditions.
- Weather change.
- Pregnancy (first trimester).
- Fatigue.
- Professional activities that are associated with lack of sleep, work in a hot climate, increased sweating.
But there are also a number of pathologies in which a persistent decrease in upper pressure develops:
- Bradycardia.
- Pathology of the valvular apparatus.
- Intoxication.
- Brain injury.
- Diabetes.
- Vegetative-vascular dystonia.
- neuroses.
- Blood loss.
- Injuries of the cervical spine.
- Cardiogenic shock, shock - arrhythmogenic, hemorrhagic, anaphylactic, septic, hypovolemic.
- Starvation.
- Consequence of uncontrolled intake of antihypertensive drugs.
A person who has lowered upper pressure feels:
- Fatigue.
- Prostration.
- Bad mood.
- Apathy.
- Drowsiness.
- Irritability.
- Increased sweating.
- Decreased memory.
- Decreased ability to concentrate on anything.
In any case, regardless of whether high or low upper pressure, it is necessary to monitor your body, diagnose and treat if necessary.
What does low pressure mean
The indicators of this value depend on such factors:
- Elasticity of the walls of the aorta and arteries.
- Pulse rate.
- The total volume of blood.
If it happens that when measuring pressure, diastolic is elevated in rare cases, then this is not considered a pathology. Such a reaction of our cardiovascular system can be caused by:
- Psycho-emotional overload.
- Expressed physical activity.
- Meteorological dependence.
The same can be said about a decrease in diastolic pressure, but in most cases, low lower pressure and its causes must be carefully diagnosed,
Increasing the lower pressure
You can talk about hypertension in cases where diastolic pressure is persistently elevated. Low pressure is high in the following situations:
- Kidney diseases.
- Renal hypertension.
- Pathology of the spine.
- Dysfunction of the thyroid gland, adrenal glands.
The most common symptoms of high blood pressure are:
- Pain in the chest area.
- Vertigo.
- Labored breathing.
- Visual impairment (with a long process).
Lower pressure reduction
- Tuberculosis.
- Allergy.
- aortic dysfunction.
- Dehydration.
- Pregnancy.
When low pressure is lowered, a person may experience the following symptoms:
- Lethargy.
- Brokenness.
- Weakness.
- Drowsiness.
- Pain in various parts of the head and dizziness.
- Poor appetite or lack of it.
Pressure rate
At systolic pressure, the norm can vary from a maximum of 110 to 139 mm Hg. Art., and for diastolic pressure, the norm is not less than 70 and not more than 89 mm Hg. Art.
In a healthy state of the body, the optimal blood pressure is 120/80 millimeters of mercury (mm Hg).
The pressure in the cardiovascular system is created by the coordinated work of the heart and blood vessels, and therefore each of the pressure indicators characterizes a certain stage of the heart's activity:
- Upper (systolic) pressure - shows the level of pressure during systole - the maximum contraction of the heart.
In addition to the norm of indicators such as upper and lower pressure, the difference between them is also taken into account, which is also an important figure.
Since the normal pressure in humans is 120/80 mm Hg. Art., it is clear that the normal difference between systolic and diastolic pressure is 40 mm Hg. Art. This difference is called pulse pressure. If there is an increase or decrease in such a difference, then we are talking about the pathology of not only the cardiovascular system, but also a large number of other diseases.
The level of pulse pressure is primarily affected by the distensibility of the aorta and those vessels that are located nearby.
The aorta has a high ability to stretch. The older a person becomes, the more its elastic properties decrease due to tissue wear. Over time, the elastic fibers in the aorta are replaced by connective tissue - collagen fibers, which are no longer so extensible, but are more rigid.
In addition, the aging of the human body leads to the fact that cholesterol, lipids, calcium salts and other substances begin to be deposited on the walls of blood vessels, which interfere and prevent the aorta from fully realizing its functions.
That is why, with a large value of pulse pressure in the elderly, it is recommended to follow medical recommendations, as this indicates a high risk of stroke and other cardiovascular complications.
How to measure correctly
Pressure is measured in millimeters of mercury. The devices that are currently used to determine blood pressure are quite simple to use. This allows everyone to control the numbers of their pressure at any time of the day, even on a walk.
Nevertheless, there are rules that must be followed in order to correctly measure the upper and lower pressure:
- Before measuring pressure, you need to rest for 5-10 minutes.
- When measuring pressure, you must sit, your back should rest on the back of the chair, and the arm on which the pressure is measured should be comfortably and motionless on the table from the elbow to the fingers.
- The shoulder should not be squeezed by clothing.
- The blood pressure cuff should be worn with the center of the inflatable bag directly over the brachial artery.
- The lower edge of the cuff should be fixed 2-3 cm above the elbow.
- The inflatable bag itself should be at the level of the heart when measuring pressure.
- The legs should be kept bent and the feet should be flat on the floor.
- The bladder must be emptied.
The above rules relate to the procedure for measuring pressure with a tonometer. But the rules for measuring with automatic devices for home use are prescribed in the instructions for the device. However, the basic provisions in these instructions are the same, with the exception of the position of the device itself and the position of the hand with the device.
If these conditions are not met, the real pressure figures are distorted and the difference will approximately be as follows:
- After smoking - 6/5 mm Hg. Art.
- After taking coffee, strong tea - by 11/5 mm Hg. Art.
- After alcohol - 8/8 mm Hg. Art.
- With a full bladder - 15/10 mm Hg. Art.
- Lack of support for the arm - 7/11 mm Hg. Art.
- Lack of support for the back - fluctuations in systolic pressure by 6-10 mHg. Art.
Options for the ratio of upper and lower pressures
In different situations, the picture of blood pressure may be different:
- The upper pressure is high, the lower one is lowered / normal - this phenomenon is typical for isolated arterial hypertension. Such hypertension is primary and secondary. The primary process occurs due to age-related vascular changes, more common in older patients.
Treatment
Treatment of an imbalance of upper and lower pressure must begin with a thorough diagnosis, because there are a lot of reasons for their change. It is not always possible to completely return the pressure to normal, but it is possible to reliably control it with the help of antihypertensive drugs and other means.
Forecast
A decrease in upper and lower pressure can also lead to unpleasant consequences - strokes, cardiogenic shock, collapse, loss of consciousness.
With hypotension, the body, heart and blood vessels are completely rebuilt, which leads to the development of a special form of hypertension, which is very difficult to treat.
It must be remembered that any fluctuation of the upper or lower pressure should be a reason to see a doctor.
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Arterial pressure
Blood pressure in the cavities of the heart and blood vessels
Blood pressure is one of the leading parameters of hemodynamics, which characterizes the force exerted by the blood flow on the walls of blood vessels.
Blood pressure depends on the amount of blood ejected by the heart into the arteries and on the total peripheral resistance that blood encounters as it flows through the arteries, arterioles, and capillaries.
To determine the value of blood pressure in humans, use the method proposed by N.S. Korotkov. For this purpose, a Riva-Rocci sphygmomanometer is used. In humans, the value of blood pressure in the brachial artery is usually determined. To do this, a cuff is placed on the shoulder and air is forced into it until the arteries are completely compressed, an indicator of which may be the cessation of the pulse.
If the pressure in the cuff is raised above the level of systolic blood pressure, then the cuff completely blocks the lumen of the artery and blood flow in it stops. There are no sounds. If we now gradually release air from the cuff, then at the moment when the pressure in it becomes slightly lower than the systolic arterial level, the blood during systole overcomes the squeezed area. A blow against the wall of the artery of a portion of blood moving with great speed and kinetic energy through the squeezed area generates a sound heard below the cuff. The pressure in the cuff at which the first sounds appear in the artery corresponds to the maximum, or systolic, pressure. With a further decrease in pressure in the cuff, there comes a moment when it becomes lower than diastolic, blood begins to pass through the artery both during systole and during diastole. At this point, the sound in the artery below the cuff disappears. The value of the pressure in the cuff at the time of the disappearance of sounds in the artery is judged on the value of the minimum, or diastolic, pressure.
The maximum pressure in the brachial artery in an adult healthy person is on average equal to mm Hg. Art., and the minimum is mm Hg. Art. An increase in blood pressure leads to the development of hypertension, a decrease - to hypotension.
Normal blood pressure values depending on age
The difference between the maximum and minimum pressure is called pulse pressure.
Arterial blood pressure rises under the influence of various factors: when performing physical work, in various emotional states (fear, anger, fright, etc.); it also depends on age.
Rice. 1. The value of systolic and diastolic pressure depending on age
Blood pressure in the chambers of the heart
The blood pressure in the cavities of the heart depends on a number of factors. Among them, the force of contraction and the degree of relaxation of the myocardium, the volume of blood filling the cavities of the heart, the blood pressure in the vessels from which blood flows during diastole and into which blood is expelled during systole. Blood pressure in the left atrium ranges from 4 mm Hg. Art. in diastole up to 12 mm Hg. Art. in systole, and in the right - from 0 to 8 mm Hg. Art. Blood pressure in the left ventricle at the end of diastole is 4-12 mm Hg. Art., and at the end of systole -mm Hg. Art. In the right ventricle, it is at the end of diastole 0-8 mm Hg. Art., and at the end of systole -mm Hg. Art. Thus, the range of fluctuations in blood pressure in the left ventricle is mm Hg. Art., and in the right - 0-28 mm Hg. Art. Blood pressure in the cavities of the heart is measured during sounding of the heart using pressure sensors. Its values are important for assessing the state of the myocardium. In particular, the rate of increase in blood pressure during ventricular systole is one of the most important characteristics of their myocardial contractility.
Rice. 2. Graph of changes in blood pressure in various parts of the cardiovascular system
Blood pressure in arteries
Blood pressure in the arterial vessels, or blood pressure, is one of the most important indicators of hemodynamics. It arises as a result of the action of two oppositely directed forces on the blood. One of them is the force of the contracting myocardium, the action of which is aimed at promoting blood in the vessels, and the second is the force of resistance to blood flow, due to the properties of the vessels, the mass and properties of blood in the vascular bed. Blood pressure in the arterial vessels depends on three main components of the cardiovascular system: the work of the heart, the condition of the vessels, the volume and properties of the blood circulating in them.
Factors that determine blood pressure:
- blood pressure is calculated by the formula:
BP = IOC OPSS, where BP is blood pressure; IOC - minute volume of blood; OPSS - total peripheral vascular resistance;
Factors that determine venous pressure:
- residual driving force of heart contractions;
- vein tone and their general resistance;
- volume of circulating blood;
- contraction of skeletal muscles;
- respiratory movements of the chest;
- suction action of the heart;
- change in hydrostatic pressure at various positions of the body;
- the presence of regulatory factors that reduce or increase the lumen of the veins
The magnitude of blood pressure in the aorta and large arteries predetermines the gradient of blood pressure in the vessels of the entire systemic circulation and the magnitude of the volumetric and linear blood flow velocities. The blood pressure in the pulmonary artery determines the nature of the blood flow in the vessels of the pulmonary circulation. The value of arterial blood pressure is one of the vital constants of the body, which is regulated by complex, multi-circuit mechanisms.
Methods for determining blood pressure
Due to the importance of this indicator for the life of the body, blood pressure is one of the most frequently assessed indicators of blood circulation. This is also due to the relative availability and simplicity of methods for determining blood pressure. Its measurement is a mandatory medical procedure when examining sick and healthy people. When significant deviations of blood pressure from normal values are detected, methods of its correction are used, based on knowledge of the physiological mechanisms of blood pressure regulation.
Pressure Measurement Methods
- Direct invasive pressure measurement
- Non-invasive methods:
- Riva-Rocci method;
- auscultatory method with registration of tones N.S. Korotkov;
- oscillography;
- tachooscillography;
- angiotensiotonography according to N.I. Arinchin;
- electrosphygmomanometry;
- ambulatory blood pressure monitoring
Arterial blood pressure is determined by two methods: direct (bloody) and indirect.
With the direct method of measuring blood pressure, a hollow needle or glass cannula is inserted into the artery, connected to a manometer by a tube with rigid walls. The direct method of determining blood pressure is the most accurate, but it requires surgical intervention and is therefore not used in practice.
Later, to determine the systolic and diastolic pressure, N.S. Korotkov developed an auscultatory method. He suggested listening to vascular tones (sound phenomena) that occur in the artery below the cuff. Korotkov showed that in an uncompressed artery, sounds are usually absent during the movement of blood. If the pressure in the cuff is raised above the systolic pressure, then the blood flow in the clamped brachial artery stops and there are also no sounds. If you gradually release air from the cuff, then at the moment when the pressure in it becomes slightly lower than systolic, the blood overcomes the squeezed area, hits the wall of the artery and this sound is picked up when listening below the cuff. The indication of the manometer at the appearance of the first sounds in the artery corresponds to the systolic pressure. As the pressure in the cuff decreases further, the sounds first increase and then disappear. Thus, the pressure gauge reading at this moment corresponds to the minimum - diastolic - pressure.
The external indicators of the beneficial result of the tonic activity of the vessels are: arterial pulse, venous pressure, venous pulse.
Arterial pulse - rhythmic oscillations of the arterial wall caused by a systolic increase in pressure in the arteries. A pulse wave occurs in the aorta at the moment of expulsion of blood from the ventricle, when the pressure in the aorta rises sharply and its wall grows in writing. The wave of increased pressure and the oscillation of the vascular wall caused by this stretching propagate at a certain speed from the aorta to the arterioles and capillaries, where the pulse wave goes out. The pulse curve registered on a paper tape is called a sphygmogram.
On the sphygmograms of the aorta and large arteries, two main parts are distinguished: the rise of the curve - anacrota and the decline of the curve - catacrota. Anacrota is caused by a systolic increase in pressure and stretching of the arterial wall by blood ejected from the heart at the beginning of the exile phase. Catacrot occurs at the end of the systole of the ventricle, when the pressure in it begins to fall and the pulse curve declines. At the moment when the ventricle begins to relax and the pressure in its cavity becomes lower than in the aorta, the blood ejected into the arterial system rushes back to the ventricle. During this period, the pressure in the arteries drops sharply and a deep notch appears on the pulse curve - an incisura. The movement of blood back to the heart encounters an obstacle, since the semilunar valves close under the influence of the reverse flow of blood and prevent its entry into the left ventricle. The blood wave reflects off the valves and creates a secondary pressure wave called dicrotic rise.
Rice. 3. Arterial sphygmogram
The pulse is characterized by frequency, filling, amplitude and rhythm of tension. Pulse of good quality - full, fast, full, rhythmic.
The venous pulse is noted in large veins near the heart. It is caused by obstruction of blood flow from the veins to the heart during atrial and ventricular systole. A graphical recording of a venous pulse is called a phlebogram.
Daily monitoring of blood pressure - measurement of blood pressure for 24 hours in automatic mode, followed by decoding of the record. Blood pressure parameters vary throughout the day. In a healthy person, blood pressure begins to increase at 6.00, reaches its maximum values by 14.00-16.00, decreases after 21.00 and becomes minimal during night sleep.
Rice. 4. Daily fluctuations in blood pressure
Systolic, diastolic, pulse and mean hemodynamic pressure
The pressure exerted on the wall of an artery by the blood in it is called blood pressure. Its value is determined by the strength of heart contractions, blood flow into the arterial system, cardiac output, elasticity of vessel walls, blood viscosity and a number of other factors. Distinguish between systolic and diastolic blood pressure.
Systolic blood pressure is the maximum pressure that occurs at the time of a heartbeat.
Diastolic pressure is the lowest pressure in the arteries when the heart relaxes.
The difference between systolic and diastolic pressure is called pulse pressure.
Mean dynamic pressure is the pressure at which, in the absence of pulse fluctuations, the same hemodynamic effect is observed as with natural fluctuating blood pressure. The pressure in the arteries during ventricular diastole does not drop to zero, it is maintained due to the elasticity of the arterial walls, stretched during systole.
Rice. 5. Factors that determine mean arterial pressure
Systolic and diastolic pressure
Systolic (maximum) blood pressure is the highest amount of pressure exerted by blood on the wall of the arteries during ventricular systole. The value of systolic blood pressure depends mainly on the work of the heart, but its value is influenced by the volume and properties of circulating blood, as well as the state of vascular tone.
Diastolic (.minimum) blood pressure is called its lowest level, to which the blood pressure in large arteries decreases during ventricular diastole. The value of diastolic blood pressure depends mainly on the state of vascular tone. However, an increase in diastolic blood pressure can be observed against the background of high values of the IOC and heart rate with normal or even reduced total peripheral resistance to blood flow.
The normal level of systolic pressure in the brachial artery for an adult is usually in the range of mm Hg. Art. The normal range for diastolic pressure in the brachial artery is mm Hg. Art.
Cardiologists distinguish the concept of the optimal level of blood pressure when the systolic pressure is slightly less than 120 mm Hg. Art., and diastolic less than 80 mm Hg. Art.; normal - systolic less than 130 mm Hg. Art. and diastolic less than 85 mm Hg. Art.; high normal level at systolic pressure mm Hg. Art. and diastolic mm Hg. Art. Despite the fact that with age, especially in people over 50 years old, blood pressure usually increases gradually, it is currently not customary to talk about the age-related increase in blood pressure. With an increase in systolic pressure above 140 mm Hg. Art., and diastolic above 90 mm Hg. Art. it is recommended to take measures to reduce it to normal values.
Table 1. Normal values of arterial pressure depending on age
Arterial pressure, mm Hg Art.
An increase in blood pressure above a high normal level (above 140 mm Hg systolic and above 90 mm Hg diastolic) is called hypertension (from Latin tensio - tension, stretching of the vessel wall), and a decrease in pressure beyond the lower limit ( below 110 mm Hg for systolic and 60 mm Hg for diastolic) - hypotension. Also denote the most common diseases of the cardiovascular system. Often these diseases are called the terms hypertension and hypotension, which emphasize that the most common causes of an increase or decrease in blood pressure is an increase or decrease in the tone of smooth myocytes in the walls of muscular arterial vessels. There are cases of an isolated increase in only systolic blood pressure and, if this increase exceeded 140 mm Hg. Art. (with diastolic pressure less than 90 mm Hg), it is customary to speak of isolated systolic hypertension.
An increase in predominantly systolic blood pressure is a natural physiological response of the cardiovascular system to exercise, associated with the need to increase the volumetric and linear blood flow rates in the body. Therefore, one of the requirements for the correct measurement of blood pressure in humans is its measurement at rest.
Table 2. Types of blood pressure
Rise in pressure to a maximum during systole
Decrease in pressure to a minimum during diastole
The amplitude of pressure fluctuations throughout the cardiac cycle
Pressure averaged over the time of the cardiac cycle, i.e. such pressure that would be in the vascular system without rise in systole, decline in diastole and the work of the heart in the form of a constant pump
The force with which blood acts on the vessel wall
The sum of potential and kinetic energies possessed by blood moving in a certain section of the vascular bed
Difference between end and side pressure
Pulse pressure
The difference between the values of systolic (BP syst) and diastolic (BP diast) blood pressure is called pulse pressure.
The most important factors influencing the value of pulse pressure are the stroke volume (SV) of the blood expelled by the left ventricle and the extensibility (C) of the aortic and arterial wall. This reflects the expression P p = UO / C, showing that the pulse pressure is directly proportional to the stroke volume and inversely proportional to the extensibility of the vessels.
It follows from the above expression that with a decrease in the extensibility of the aorta and arteries, even under conditions of a constant stroke volume of blood, the pulse pressure will increase. This is exactly what happens in older people due to sclerosis of the aorta and arteries and a decrease in their elasticity and extensibility.
The value of pulse pressure can change both under normal conditions and in diseases of the cardiovascular system. For example, during exercise in a healthy person, pulse pressure increases, but this can also occur with isolated systolic hypertension, mentioned above. A decrease in pulse blood pressure in patients with heart disease may be a sign of a deterioration in its pumping function and the development of heart failure.
Average dynamic pressure
Mean hemodynamic pressure (BP sgd). The value of blood pressure changes during the cardiac cycle from the maximum during systole to the minimum during diastole. For most of the duration of the cardiac cycle, the heart is in diastole and the BP value is closer to the diastolic BP. Thus, blood pressure during the cardiac cycle can be expressed as an average value, or blood pressure sg, which provides a volumetric blood flow equal to the blood flow created by changing blood pressure from systolic to diastolic. The blood pressure gradient is the main driving force of blood flow and its magnitude changes during the cardiac cycle, so the blood flow in the arterial vessels is pulsatile. It accelerates in systole and slows down in diastole. The value of blood pressure sgd for large central arteries is determined by the formula
According to this formula, the mean hemodynamic pressure is equal to the sum of the diastolic pressure and half the pulse pressure. For peripheral arteries, BP sgp is calculated by adding diast to the BP indicator by a third of the pulse pressure value:
The use of the BP indicator is convenient for analyzing the factors affecting the level of blood pressure in the vessels and identifying the reasons for its deviation from the norm. To do this, we must recall the formula of the basic equation of hemodynamics that we previously considered:
Transforming it, we get:
From this formula it follows that the main factors on which the value of arterial blood pressure depends, and the reasons for its change are the minute volume of blood ejected by the left ventricle into the aorta (i.e., the state of the pumping function of the heart), and the value of the OPS to the blood flow.
A person of middle age and body weight for the normal functioning of the body in a state of physiological and psychological rest needs an IOC of about 5 l / min. If at the same time the OPS is 20 mm Hg. Art. / l / min, then to ensure the IOC 5 l / min, it is necessary that an average hemodynamic pressure of 100 mm Hg be maintained in the aorta. Art. (5 * 20 = 100). If in such a person OPS increases (this can occur due to narrowing of resistive vessels as a result of an increase in the tone of smooth muscle fibers, narrowing of arterial vessels as a result of their sclerosis), for example, up to 30 mm Hg. Art. / l / min, then to ensure sufficient IOC (5 l / min), an increase in blood pressure sgd to 150 mm Hg will be required. Art. (5 * 30 = 150). To achieve higher blood pressure, sgp must be higher systolic and diastolic blood pressure.
To restore the normal level of blood pressure in this case, a person will be shown taking drugs that reduce the OPS (vasodilating, lowering blood viscosity, preventing vascular sclerosis).
To understand the mechanisms and correct diagnosis of circulatory disorders, it is important to know not only the magnitude of systolic, diastolic, pulse and mean hemodynamic pressure, but also their relationship, as well as factors affecting them. So, with a rapid increase in blood pressure, to lower it, the use of not only vasodilators is shown, but also a complex effect on the causal factors on which the magnitude of blood pressure depends (heart function, volume and properties of circulating blood, vascular condition). Since IOC \u003d UO * HR, it is possible to reduce it and blood pressure by using drugs that block β1-adrenergic receptors and (or) calcium channels of cardiomyocytes. At the same time, both heart rate and SV decrease. In addition, the use of calcium channel blockers is accompanied by relaxation of smooth myocytes of the vascular wall, vasodilation and a decrease in OPS, which contribute to a drop in blood pressure. To reduce BCC, as another powerful factor influencing the magnitude of blood pressure, they resort to the use of diuretics. The use of an integrated approach to the correction of blood pressure will usually give the best results.
Arterial pressure. Systolic and diastolic blood pressure
/ Hemodynamic parameters
Hemodynamic parameters. The ratio of the main parameters of systemic hemodynamics. Parameters of systemic hemodynamics - systemic arterial pressure, peripheral vascular resistance, cardiac output, heart function, venous return, central venous pressure, circulating blood volume - are in complex, finely regulated relationships, which allows the system to perform its functions. Thus, a decrease in pressure in the carotid sinus zone causes an increase in systemic arterial pressure, an increase in heart rate, an increase in total peripheral vascular resistance, heart function and venous return of blood to the heart. Minute and systolic volume of blood can change in this case ambiguously. An increase in pressure in the carotid sinus zone causes a decrease in systemic arterial pressure, a slowdown in heart rate, a decrease in total vascular resistance and venous return, and a decrease in heart work. Changes in cardiac output are pronounced, but ambiguous in direction. The transition from a horizontal position of a person to a vertical position is accompanied by the consistent development of characteristic changes in systemic hemodynamics. These shifts include both primary and secondary compensatory changes in the circulatory system, which are schematically presented in Table. 9.5. It is important to maintain a constant ratio between the volume of blood contained in the systemic circulation and the volume of blood in the chest organs (lungs, heart cavities). The vessels of the lungs contain up to 15%, and in the cavities of the heart (in the diastole phase) - up to 10% of the total blood mass; Based on the foregoing, the central (intrathoracic) blood volume can be up to 25% of the total amount of blood in the body.
The extensibility of the vessels of the small circle, especially the pulmonary veins, allows the accumulation of a significant volume of blood in this area with an increase in venous return to the right half of the heart. Accumulation of blood in a small circle occurs in people during the transition of the body from a vertical to a horizontal position, while up to 600 ml of blood can move into the vessels of the chest cavity from the lower extremities, of which about half accumulates in the lungs. On the contrary, when the body moves to a vertical position, this volume of blood passes into the vessels of the lower extremities. The lung blood reserve is used when urgent mobilization of additional blood is needed to maintain proper cardiac output. This is especially important at the beginning of intensive muscular work, when, despite the activation of the muscle pump, the venous return to the heart does not yet reach a level that ensures cardiac output in accordance with the oxygen demand of the body.
One of the sources that provide a reserve of cardiac output is also the residual volume of blood in the cavity of the ventricles. In the horizontal position of a person, the residual volume of the left ventricle is on average 100 ml, and in the vertical position - 45 ml. Close to these values are typical for the right ventricle. The increase in stroke volume observed during muscular work or the action of catecholamines, which is not accompanied by an increase in the size of the heart, occurs due to the mobilization, mainly, of a part of the residual blood volume in the cavity of the ventricles. Thus, along with changes in venous return to the heart, the factors that determine the dynamics of cardiac output include: the volume of blood in the pulmonary reservoir, the reactivity of the vessels of the lungs, and the residual volume of blood in the ventricles of the heart.
Blood pressure is the pressure that blood exerts on the walls of blood vessels, or, in other words, the excess pressure of the fluid in the circulatory system over atmospheric pressure, one of the important signs of life. Most often, this concept means blood pressure. In addition to it, the following types of blood pressure are distinguished: intracardiac, capillary, venous. With each heartbeat, blood pressure fluctuates between the lowest (diastolic) and highest (systolic)
Blood pressure is one of the most important parameters characterizing the work of the circulatory system. Blood pressure is determined by the volume of blood pumped per unit time by the heart and the resistance of the vascular bed. Since the blood moves under the influence of the pressure gradient in the vessels created by the heart, the highest blood pressure will be at the outlet of the blood from the heart (in the left ventricle), a slightly lower pressure will be in the arteries, even lower in the capillaries, and the lowest in the veins and at the entrance heart (in the right atrium). The pressure at the exit from the heart, in the aorta and in large arteries differs slightly (by 5-10 mm Hg), because due to the large diameter of these vessels, their hydrodynamic resistance is small. In the same way, the pressure in the large veins and in the right atrium differs slightly. The greatest drop in blood pressure occurs in small vessels: arterioles, capillaries and venules.
Top number - systolic blood pressure, shows the pressure in the arteries at the moment when the heart contracts and pushes blood into the arteries, it depends on the strength of the contraction of the heart, the resistance exerted by the walls of the blood vessels, and the number of contractions per unit of time.
Bottom number - diastolic blood pressure, shows the pressure in the arteries at the moment of relaxation of the heart muscle. This is the minimum pressure in the arteries, it reflects the resistance of the peripheral vessels. As blood moves along the vascular bed, the amplitude of blood pressure fluctuations decreases, venous and capillary pressure are little dependent on the phase of the cardiac cycle.
Typical healthy human arterial blood pressure (systolic/diastolic) = 120 and 80 mm Hg. Art., pressure in large veins by a few mm. rt. Art. below zero (below atmospheric). The difference between systolic blood pressure and diastolic (pulse pressure) is normally 30-40 mm Hg. Art.
The most easy to measure blood pressure. It can be measured using a sphygmomanometer (tonometer). That is what is usually meant by blood pressure.
Modern digital semi-automatic tonometers allow you to limit yourself to only a set of pressure (up to a sound signal), further pressure relief, registration of systolic and diastolic pressure, sometimes - pulsaiarrhythmia, the device performs itself.
Automatic blood pressure monitors themselves pump air into the cuff, sometimes they can give out data in digital form, for transmission to a computer or other devices.
Factors that determine the value of blood pressure: the amount of blood, the elasticity of the vascular wall and the total value of the lumen of the vessels. With an increase in the amount of blood in the vascular system, the pressure increases. With a constant amount of blood, the expansion of blood vessels (arterioles) leads to a decrease in pressure, and their narrowing leads to an increase.
There are no pulse fluctuations in blood pressure in small and medium sized veins. In the large veins near the heart, pulse fluctuations are noted - the venous pulse, which is due to the difficulty in the outflow of blood to the heart during atrial and ventricular systole. With the contraction of these parts of the heart, the pressure inside the veins increases and their walls oscillate. It is most convenient to record the pulse of the jugular vein (v. jugularis).
On the jugular vein pulse curve - a jugular phlebogram - of a healthy adult, each cardiac cycle is represented by three positive (a, c, v) and two negative (x, y) waves (Fig.), Reflecting mainly the work of the right atrium.
The prong "a" (from the Latin atrium - atrium) coincides with the systole of the right atrium. It is caused by the fact that at the moment of atrial systole, the mouths of the hollow veins flowing into it are clamped by a ring of muscle fibers, as a result of which the outflow of blood from the veins into the atria is temporarily suspended. Therefore, with each atrial systole, there is a short-term stagnation of blood in large veins, which causes stretching of their walls.
The "c" wave (from Latin carotis - carotid [artery]) is caused by the push of the pulsating carotid artery, which lies near the jugular vein. Occurs at the beginning of the systole of the right ventricle when the tricuspid valve closes and coincides with the beginning of the rise of the carotid sphygmogram (systolic wave of the carotid pulse).
During atrial diastole, blood access to them again becomes free and at this time the venous pulse curve drops steeply, a negative “x” wave (systolic collapse wave) occurs, which reflects the accelerated outflow of blood from the central veins into the relaxing atrium during ventricular systole. The deepest point of this wave coincides in time with the closing of the semilunar valves.
Sometimes, on the lower part of the "x" wave, a notch "z" is determined, corresponding to the moment of closing the valves of the pulmonary artery and coinciding in time with the II tone of the FCG.
The "v" wave (from Latin ventriculus - ventricle) is due to an increase in pressure in the veins and the difficulty of outflow of blood from them into the atria at the time of maximum filling of the atria. The apex of the "v" wave coincides with the opening of the tricuspid valve.
The subsequent rapid flow of blood from the right atrium into the ventricle during the diastole of the heart manifests itself in the form of a negative wave of the phlebogram, which is called the wave of diastolic collapse and is indicated by the symbol "y" - rapid emptying of the atria. The deepest negative point of the "y" wave coincides with the third tone of the FCG.
The most striking element on the jugular phlebogram is the wave of systolic collapse "x", which gave grounds to call the venous pulse negative.
Pathological changes in the venous pulse
with bradycardia, the amplitude of the "a" and "v" waves increases, another positive "d" wave can be registered
with tachycardia, the "y" wave decreases and flattens
in case of insufficiency of the tricuspid valve, a positive venous pulse or a ventricular form of the venous pulse is recorded, when an additional positive wave i is recorded between waves "a" and "c", which is due to regurgitation of blood through an open valve. The severity of wave i correlates with the degree of insufficiency.
with mitral stenosis, there is an increase in the amplitude of the "a" wave and a decrease in the amplitude of the "v" wave
with adhesive pericarditis, a double negative wave of the venous pulse is observed - an increased amplitude of the "a" and "v" waves and a deepening of the "x" and "y" waves
with atrial fibrillation and flutter - a significant decrease in the amplitude of the "a" wave and an increase in its duration
with an atrioventricular form of paroxysmal tachycardia, waves "a" and "c" merge, forming one big wave
with an atrial septal defect - an increase in the amplitude of the "a" wave, and when blood is discharged from left to right, its bifurcation
circulatory failure - change in waves "a", "v", "y"
stenosis of the aortic mouth - a decrease in the amplitude of the "c" wave
aortic valve insufficiency, open ductus arteriosus - an increase in the amplitude of the "c" wave, etc.
Rhythmic oscillations of the arterial wall, caused by a systolic increase in pressure in the arteries, are called the arterial pulse. The pulsation of the arteries can be easily detected by touching any palpable artery: radial, femoral, digital artery of the foot.
A pulse wave, in other words, a wave of pressure increase, occurs in the aorta at the moment of expulsion of blood from the ventricles, when the pressure in the aorta rises sharply and its wall is stretched as a result. The wave of increased pressure and the resulting fluctuation of the arterial wall propagates at a certain speed from the aorta to the arterioles and capillaries, where the pulse wave goes out.
The speed of propagation of the pulse wave does not depend on the speed of the blood flow. The maximum linear velocity of blood flow through the arteries does not exceed 0.3-0.5 m/s, and the propagation velocity of the pulse wave in young and middle-aged people with normal blood pressure and normal elasticity of blood vessels is 5.5-8.0 m in the aorta / sec, and in the peripheral arteries - 6-9.5 m / sec. With age, as the elasticity of the vessels decreases, the speed of propagation of the pulse wave, especially in the aorta, increases.
A detailed analysis of arterial pulse fluctuations is performed on the basis of a sphygmogram.
In the pulse curve (sphygmogram) of the aorta and large arteries, two main parts are distinguished:
anacrota, or rising curve
catacrot, or descent of a curve
The anacrotic rise reflects the flow of blood into the artery ejected from the heart at the beginning of the ejection phase, which leads to an increase in blood pressure and the resulting stretching that the walls of the arteries undergo. The top of this wave at the end of the systole of the ventricle, when the pressure in it begins to fall, passes into the descent of the curve - catacrot. The latter corresponds in time to the phase of slow expulsion, when the outflow of blood from the stretched elastic arteries begins to predominate over the inflow.
The end of the systole of the ventricle and the beginning of its relaxation leads to the fact that the pressure in its cavity becomes lower than in the aorta; blood ejected into the arterial system rushes back to the ventricle; the pressure in the arteries drops sharply, and a deep recess appears on the pulse curve of the large arteries - an incisura. The lowest point of the incisura corresponds to the complete closure of the aortic semilunar valves, which prevent the return of blood to the ventricle.
The wave of blood is reflected from the valves and creates a secondary wave of pressure increase, causing the arterial walls to stretch again. As a result, a secondary, or dicrotic, rise appears on the sphygmogram - stretching of the aortic walls due to the reflection of a blood wave from closed semilunar valves. The subsequent smooth descent of the curve corresponds to a uniform outflow of blood from the central vessels to the distal ones during diastole.
The forms of the pulse curve of the aorta and the large vessels extending directly from it, the so-called central pulse, and the pulse curve of the peripheral arteries are somewhat different (Fig.).
Study of the arterial pulse
By simple palpation of the pulse of the superficial arteries (for example, the radial artery in the hand), important preliminary information about the functional state of the cardiovascular system can be obtained. In this case, a number of pulse properties are evaluated (pulse quality):
Pulse rate per minute - characterizes the heart rate (normal or fast pulse). When assessing the pulse rate, it should be remembered that children have a faster resting pulse than adults. Athletes have a slow heart rate. The acceleration of the pulse is observed with emotional arousal and physical work; at maximum load in young people, the heart rate can increase to 200/min or more.
Rhythm (rhythmic or arrhythmic pulse). The pulse rate may fluctuate in accordance with the rhythm of breathing. When you inhale, it increases, and when you exhale, it decreases. This "respiratory arrhythmia" is observed normally, and it becomes more pronounced with deep breathing. Respiratory arrhythmia is more common in young people and in individuals with a labile autonomic nervous system. Accurate diagnosis of other types of arrhythmias (extrasystoles, atrial fibrillation, etc.) can only be made using an ECG.
Height - pulse amplitude - the amount of fluctuation of the arterial wall during a pulse impulse (high or low pulse). The amplitude of the pulse depends primarily on the magnitude of the stroke volume and the volumetric blood flow velocity in diastole. It is also affected by the elasticity of shock-absorbing vessels: with the same stroke volume, the smaller the pulse amplitude, the greater the elasticity of these vessels, and vice versa.
The speed of the pulse is the rate at which the pressure in the artery rises at the time of anacrosis and decreases again at the time of catacrosis (fast or slow pulse). The steepness of the rise of the pulse wave depends on the rate of pressure change. With the same heart rate, rapid changes in pressure are accompanied by a high pulse, and less rapid changes are accompanied by a low one.
A fast pulse occurs with aortic valve insufficiency, when an increased amount of blood is ejected from the ventricles, some of which quickly returns through the valve defect to the ventricle. A slow pulse occurs when the aortic orifice narrows, when blood is expelled more slowly than normal into the aorta.
The tension of the pulse or its hardness (hard or soft pulse). The voltage of the pulse depends mainly on the mean arterial pressure, since this characteristic of the pulse is determined by the amount of effort that must be applied so that the pulse in the distal (located below the clamping point) part of the vessel disappears, and this effort changes with fluctuations in the mean arterial pressure. By the voltage of the pulse, one can approximately judge the systolic pressure.
The shape of the pulse wave can be examined using relatively simple techniques. The most common method in the clinic is to place sensors on the skin that record either changes in pressure (sphygmography) or changes in volume (plethysmography).
Pathological changes in the arterial pulse
Having determined the shape of the pulse wave, it is possible to draw important diagnostic conclusions about the hemodynamic shifts occurring in the arteries as a result of changes in stroke volume, vascular elasticity and peripheral resistance.
On fig. the pulse curves of the subclavian and radial arteries are shown. Normally, a rise is recorded on the recording of the pulse wave during almost the entire systole. With increased peripheral resistance, such a rise is also observed; with a decrease in resistance, a primary peak is recorded, followed by a lower systolic rise; then the amplitude of the wave falls rapidly and passes into a relatively flat diastolic region.
A decrease in stroke volume (for example, as a result of blood loss) is accompanied by a decrease and rounding of the systolic peak and a slowdown in the rate of decrease in the wave amplitude in diastole.
Decrease in aortic distensibility (for example, in atherosclerosis) is characterized by a steep and high leading edge, a high location of the incisura, and a gentle diastolic decline.
With aortic defects, changes in the pulse wave correspond to hemodynamic shifts: with aortic stenosis, a slow gentle systolic rise is observed, and with aortic valve insufficiency, a steep and high rise; with a severe degree of insufficiency - the disappearance of the incisura.
The shift in time of the pulse curves recorded simultaneously at different points (the slope of the dashed straight lines in the figure) reflects the propagation velocity of the pulse wave. The smaller this shift (i.e., the greater the slope of the dashed lines), the higher the pulse wave propagation velocity, and vice versa.
Practically important data for judging cardiac activity in some of its disorders can be obtained by simultaneously recording an electrocardiogram and a sphygmogram on the same film.
Sometimes there is a so-called pulse deficit, when not every wave of excitation of the ventricles is accompanied by the release of blood into the vascular system and a pulse impulse. Some ventricular systoles are so weak due to a small systolic ejection that they do not cause a pulse wave reaching the peripheral arteries. In this case, the pulse becomes irregular (pulse arrhythmia).
Sphygmography is a method of graphic registration of the arterial pulse. There are two types of methods for recording pulse curves, which V. L. Kariman (1963) proposed to call direct and volumetric sphygmography. A straight, or ordinary, sphygmogram characterizes the degree of deformation of the vascular wall in a given limited area of an arterial vessel, which occurs under the influence of alternating blood pressure throughout the cardiac cycle (Savitsky N. N., 1956). The sphygmogram is usually recorded using pilot sensors or receivers, as well as funnels with air transmission, superimposed on places where vascular pulsation is usually well palpated.
In case of occlusive and stenosing lesions of the arteries of the extremities, it is advisable to use volumetric sphygmography, which registers the total fluctuations of the vascular wall, converted into fluctuations in the volume of the studied area of the limb, and creates a general idea of the collateral and main blood supply to the limb at the studied level. Volumetric sphygmography allows you to register blood flow and pulsation at any level of the limb, and direct sphygmography - pulse fluctuations only at certain points of the arm and leg. Volumetric sphygmography is a highly informative method that allows obtaining data on the nature of the lesion of the arterial system of the extremities throughout its entire length and choosing a method of treating the patient (conservative, operative), as well as evaluating the effectiveness of the treatment.
Phlebography (from Greek phléps, genitive phlebós - vein and graphy), 1) a method of X-ray examination of veins by introducing radiopaque agents into them (see also Angiography); used for varicose veins and other diseases. 2) The method of studying the blood circulation of humans and animals by graphic registration of pulse oscillations of the walls of the veins (venous pulse) - phlebosphymography. Recording curves (phlebograms) on paper, usually with the help of a mirror phlebosphygmograph, is performed mainly from the external jugular vein. There are several waves, reflecting primarily the cessation of blood flow from the vena cava to the right atrium during its contraction, the transfer of the carotid pulsation to the adjacent jugular vein during the systole of the ventricles and the filling of the right ventricle and large veins with blood during the diastole of the ventricles. F. allows you to determine the duration of cardiac phases and the tone of the right atrium; used in the diagnosis of heart defects, increased pressure in the pulmonary circulation, etc.
Rheography (from the Greek rhéos - flow, flow and graphy), a method of studying the blood filling of any part of the body by graphic registration of fluctuations in its electrical resistance. It is used in physiology and medicine. The method is based on the fact that when an alternating current of sound or supersonic frequency (16-300 kHz) is passed through a part of the body, the body's liquid media, primarily blood in large vessels, play the role of a current conductor; this makes it possible to judge the state of blood circulation in a certain area of the body or organ (for example, limbs, brain, heart, liver, lungs). Blood supply is affected by vascular tone and the total amount of blood, so R. gives an indirect idea of the peripheral resistance to blood flow in the vessels and the volume of circulating blood. The rheogram is recorded using a rheograph, consisting of a power supply, a high-frequency current generator, an amplifier, a recording device and electrodes. In medicine, R. is used as one of the diagnostic methods for diseases of the heart and blood vessels, other internal organs, as well as for blood loss and shock.
Plethysmography - registration of changes in the volume of an organ or part of the body, usually used to assess the dynamics of their blood supply. It is used to study vascular tone and its regulation.
Blood pressure (BP) is the pressure of blood in the large arteries of a person. There are two indicators of blood pressure: systolic (upper) blood pressure is the level of blood pressure at the moment of maximum contraction of the heart, diastolic (lower) blood pressure is the level of blood pressure at the time of maximum relaxation of the heart. Blood pressure is measured in millimeters of mercury and is denoted by “mm Hg. Art. It is with the measurement of blood pressure (tonometry) that it is necessary to begin the search for the cause of such frequent symptoms as headache, weakness, dizziness. In many cases, constant monitoring of blood pressure is necessary, and measurements should be taken several times a day.
Assessment of the level of blood pressure (BP)
To assess the level of blood pressure, the classification of the World Health Organization (WHO) is used.
Classification of arterial hypertension according to the level of blood pressure
Systolic blood pressure (mm Hg)
Diastolic BP (mm Hg)
Elevated normal BP
1st degree ("soft")
2nd degree (moderate)
3rd degree (severe)
* If systolic BP and diastolic BP are in different categories, the higher category is assigned.
** The risk of developing cardiovascular complications and mortality is the lowest.
The terms "mild", "borderline", "severe", "moderate", given in the classification, characterize only the level of blood pressure, and not the severity of the disease itself.
How blood pressure (BP) is measured
Two methods are used to measure blood pressure.
Korotkov method developed by the Russian surgeon N. S. Korotkov in 1905 and involves the use of a simple device consisting of a mechanical pressure gauge, a cuff with a pear and a phonendoscope. The method is based on the complete clamping of the brachial artery by the cuff and listening to the tones that occur when air is slowly released from the cuff.
Oscillometric method is based on the registration by a special electronic device of air pressure pulsations that occur in the cuff when blood passes through the compressed section of the artery.
The level of blood pressure is not a constant value, it continuously fluctuates depending on the state of the body and the action of various factors on it. Fluctuations in blood pressure in patients with arterial hypertension are significantly higher than in people without this disease. Blood pressure can be measured at rest, during physical or psycho-emotional stress, as well as in the intervals between different types of activity. Most often, blood pressure is measured in a sitting position, but in some cases it is necessary to measure it in a lying or standing position.
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The magnitude of blood pressure is mainly determined by two conditions: the energy that is reported to the blood by the heart, and the resistance of the arterial vascular system, which has to be overcome by the flow of blood flowing from the aorta. Thus, the value of blood pressure will be different in different parts of the vascular system. The greatest pressure will be in the aorta and large arteries, in small arteries, capillaries and veins it gradually decreases, in the vena cava the blood pressure is less than atmospheric pressure. The blood pressure will also be different throughout the cardiac cycle - it will be greater at the moment of systole and less at the moment of diastole. Fluctuations in blood pressure during systole and diastole of the heart occurs only in the aorta and arteries. In arterioles and veins, blood pressure is constant throughout the cardiac cycle. The greatest pressure in the arteries is called systolic, or maximum, the smallest - diastolic, or minimum. The pressure in different arteries is not the same. It can be different even in arteries with the same diameter (for example, in the right and left brachial arteries). In most people, the value of blood pressure is not the same in the vessels of the upper and lower extremities (usually the pressure in the femoral artery and arteries of the lower leg is greater than in the brachial artery), which is due to differences in the functional state of the vascular walls. At rest in healthy adults, systolic pressure in the brachial artery, where it is usually measured, is 100-140 mm Hg. Art. (1.3-1.8 atm) In young people, it should not exceed 120-125 mm Hg. Art. Diastolic pressure is 60-80 mm Hg. Art. , and is usually 10 mm higher than half the systolic pressure. A condition in which blood pressure is low (systolic below 100 mm) is called hypotension. A persistent increase in systolic (above 140 mm) and diastolic pressure is called hypertension. The difference between systolic and diastolic pressure is called pulse pressure, usually it is 50 mm Hg. Art. Blood pressure in children is lower than in adults; in older people, due to a change in the elasticity of the walls of blood vessels, it is higher than in young people. Blood pressure in the same person is not constant. It changes even during the day, for example, it increases when eating, during emotional manifestations, during physical work. Human blood pressure is usually measured in an indirect way, which was proposed by Riva-Rocci at the end of the 19th century. It is based on determining the amount of pressure required to completely compress an artery and stop blood flow in it. To do this, a cuff is placed on the limb of the subject, connected to a rubber pear, which serves to pump air, and a pressure gauge. When air is forced into the cuff, the artery is squeezed. At the moment when the pressure in the cuff becomes higher than the systolic one, the pulsation at the peripheral end of the artery stops. The appearance of the first pulse impulse when the pressure in the cuff decreases corresponds to the value of the systolic pressure in the artery. With a further decrease in pressure in the cuff, the sounds first increase and then disappear. The disappearance of sounds characterizes the magnitude of diastolic pressure. The time during which the pressure is measured should not exceed 1 min. , as blood circulation below the cuff application site may be impaired.
