Method for the diagnosis of blood flow in the brain
The invention relates to medicine, cardiology. Determine the number of microvessels, their length, diameter. According to the data obtained, calculate the exchange surface and the capacity of the microvasculature. Define systemic arterial pressure and relate it to normal levels. Choose stereological reconstruction of the desired object. Calculate the volumetric rate of blood flow in certain parts of microvessels, linear blood flow velocity in each of the microvessels, General and specific volumetric blood flow velocity. Determine the level of blood circulation in selected brain structures and diagnostic criteria of circulatory disorders of the brain in this local area. The method allows to estimate the level of blood supply of micro tissues with significant differences in the level of metabolic activity. 1 Il.
The invention relates to biology, and specifically to medicine and veterinary medicine, and is intended to assess the level of blood supply of micro tissues with significant differences in the level of metabolic activity.
A known method for studying the microcirculation of tissues (ed. mon. The USSR №1703060, And 61 In 5/02, 10/00) based on the methods of the I, that he, by showing the level of circulatory tissue in accordance with the size of the sensor and the wavelength of the used radiation, does not represent the state of blood flow in individual cells and microvascular. In addition, the method does not take into account the specific characteristics of the structure of the studied object. At the same time, it is known that close to the average value of the microcirculation may accompany a completely different features of the distribution of microvessels, and micro-sites with a high level of blood supply can coexist with itemizedoverlay areas.
The closest in technical essence of the present invention is a method for assessment of tissue blood supply of the brain, described in the book of Folkow B., Neal E. Circulation, M., 1976, S. 346-350.
The method described Folk B. and Neal E., is that the subject is breathing a gas mixture containing N2O. Then determine the arteriovenous difference N2Oh, I hope the inclusion of a substance per unit mass of brain tissue, and then use the principle of Fika to measure the mean cerebral blood flow per unit volume of the brain (specific volume of blood flow velocity). Using information on the number of vessels in the white and gray matter is este prototype is that it considers only the average circulation without considering its qualitative features (arrangement of arterioles, venules, precapillaries and postcapillary). The prototype also does not define the features of the spatial organization of the various elements of the system of microcirculation, which is necessary, for example, in the assessment of trophic security complex in structure and degree of metabolism structures (nerves, muscles, some internal organs).
The objective of the invention is to determine the parameters (indicators) of microcirculation in microsections of the internal organs, which makes it impossible or extremely difficult to direct in vivo (in vivo) studies of blood circulation, for example in the Central nervous system, heart and some other organs, and determining the level of changes in blood flow, which occurs circulatory disorders.
The technical result is achieved by the fact that according to the method for the diagnosis of blood flow in the brain to determine the number of microvessels and the total volume of the investigated area in the study area determine the efferent and bringing vessels, calculate the total length of microvessels, the surface area of all the juices of the microvessels, General and specific volume of blood flow velocity, the linear velocity of blood flow in each of microvessels by formulas Century I. George, and the coefficient of viscosity is chosen separately for each MicroSCADA depending on its radius and decreasing the linear velocity of blood flow is less than 0.08 mm/s and a specific volume of blood flow velocity less than 4.210-3mm3/mm3) diagnose circulatory disorders of the brain in this local area.
The use of the claimed invention will make it possible to predict compensatory ability of the blood supply to the brain in various physiological and pathological conditions, taking into account changes in systemic arterial pressure in a separate vascular microassay around individual cells or groups. The method does not require significant capital investment and can be applied using existing programs mathematical processing of data, such as Excel, on the basis of personal computers.
The method can be used to forecast the compensatory capacity of the microcirculation in normal and at different levels of the system circulatory disorders of the brain, and complex experimental and the violation of his blood.
The positive effect of the invention is that it allows to determine the distribution of microvessels in the structure of the audited body and simulates the hemodynamics in real objects, tentatively reconstructed by spatial reconstruction. This takes into account the following factors: the distribution of microvessels in the tissues, diagnosis, type of vessel (arteriole, capillary, venule), form capillary loops, the distribution of microvessels in relation to the structures of the body, especially the hemodynamics and the direction of blood flow in microvessels.
The invention is illustrated in the drawing, which shows a three-dimensional reconstruction of micropreparative parts motor nucleus of the trigeminal nerve of the dog. Refer to the following.
The method is implemented as follows.
Before slaughtering the animal provide measurements of systemic blood pressure by measurement of the brachial artery. Relate it to the norm. When lowering blood pressure correlated decrease to the mean arterial pressure (for example, when the measured pressure is 70/40 mm RT.article the average pressure was 55 mm RT.art., and the average boundary is 130/30 mm RT.art., that is 80 mm RT is selected indicators 1.45 times. As a result, the pressure at the arteriolar end of the capillary reduce 1.45 and received instead of 35 mm RT.article at the arterial end of the capillary in the norm metric, equal to 24.1 mm RT.article In case of an increase in blood pressure, taking into account the resistivity of blood vessels figure in the arterial end we consider the same.
Carry out histological sampling. The basic material requirements is the safety of microarchitectures vascular bed. The most adequate, for example, for small animals is the decapitation anesthetized animals, or transcardially introduction of drugs that cause acute cardiac arrest (2% aqueous solution of glutaric aldehyde). However, depending on the research objectives will be different methods of fixation or staining. If the leading is to identify active microvessels, then carry out the benzidine staining method or lifetime impose some intravital dyes (e.g., Evans blue pre-bound to albumin). To determine the maximum content of all microvessels spend their spirits ink or colloid at a gauge pressure control, with which the ordinary slices were the same thickness. Drugs Domracheva with hematoxylin, methylene or toluidine blue. After making serial sections and staining of the drug is chosen, which the researcher is interested region. Conduct spatial reconstruction of the selected area is the nerve center using the drawing apparatus RO-2 or program automated image processing. The resulting reconstruction is divided into sections (for example, volume 1, 27, 125 μm3). In the reconstructed area determine the efferent and bringing vessels. For a more precise definition set MicroSCADA find out the degree of development of the muscular layer, especially the branching vessel. After clarifying accessories MicroSCADA and direction of blood flow it is possible to determine the absolute and relative measure of the microcirculation in the considered structure. To determine the linear and volumetric blood flow velocity using the formula described. For consistently lying microvessels use the laws of parallel-serial connections. The coefficient of viscosity of the blood used in this formula, enter separately for each MicroSCADA. For vessels with a radius of from 2 to 10 μm, the coefficient of viscosity is injected according to the Faraday effect is giving brain. L:. Science, S. 89). The radius of each of the microvessels describe through the average.
The dynamics of differences in partial pressure, the degree of expansion of the blood vessels is in close connection with the change of the pulse wave that is most pronounced in bringing vessels, but at the level of the microcirculation these differences are not so significant, and in the simulation of blood flow in the system were not taken into account. Indicators of hydrostatic pressure in arterioles and venules are introduced according to known physiological constants. The gradient of pressure between microvessels be dealt with in accordance with the input of the extreme values and the level of resistance to blood flow, dependent blood viscosity, length MicroSCADA and the radius of its cross-section. After finding volumetric blood flow velocity in individual microvessels to determine the specific volumetric rate of blood flow in microvessels spatial reconstruction, calculate the linear velocity of blood flow in each of the vessels and by reducing the linear velocity of blood flow in the capillaries is less than 0.08 mm/s and a specific volume of blood flow velocity less than 4.210-3mm3/mm3) diagna dog 3 years mongrel, the weight of 5.2 kg Front face of the dog measured blood pressure in the brachial artery, which was 135/35 mm RT.art., approaching the average rate. In the result, we believe the level of hydrostatic pressure at the arterial end of the capillary is equal to 35 mm RT.article.
The slaughter was carried out under hypentelium anesthesia. Intracardiac introduced 5 ml of 1% glutaric aldehyde, which caused the cardiac arrest. After this vascular bed was washed with saline, warmed to 38C. After saline was injected heated to the same temperature a solution of carcasses with 10% solution of gelatin (1:1). The animal was deceptional. Allocated motor nucleus of the trigeminal nerve. The piece with the interests of the area was subjected to impregnation by Golgi modification Bubanee. The obtained preparations were placed in paraffin. Made serial sections with a thickness of 10 μm. Slices were dobrasil methylene blue (for the most complete identification of neurons). Under the microscope selected area for stereological reconstruction. Using the drawing apparatus RO-2 conducted a spatial reconstruction of the selected area. This identified the type of each MicroSCADA. This was followed up by a course of the drug, especially muscle wall and oodlighting nucleus of the trigeminal nerve (the drawing), which identified the following structures: n - body neurons, AST - body and appendages protoplasmatic astrocyte and arteriolar end MicroSCADA, in - venular end MicroSCADA to(1,2,3,4)- areas consistent system of microvessels, which in the example considered linear and volumetric blood flow velocity. In the proposed model the blood is sent from the arterioles to venules.
In the result of the calculation obtained: total (absolute) length of microvessels in the reconstruction amounted to 29 mm, the absolute area of the contact surface of all vessels was 5,6410-3mm2absolute blood volume in the body made up 1.2710-3mm3. Total reconstruction of 0.08 mm3. Thus, the ratios obtained by dividing the absolute figures on the volume of the reconstructed object, respectively, 3,6210-2mm/mm3, 7,0510-2mm2/mm3, 1,5910-2mm3/mm3.
The hydrostatic pressure at the arteriolar end included in the structure model of the vessel is assumed to be 35 mm RT.) - Rev. giving the brain. L:. Science, S. 91).
Let us further consider the flow in a sequential system microvessels, indicated in the drawing by the letter Ki. In the specified sequential system vessels have a first vessel (cut precapillary)1radius of 3.510-3mm and a length of 310-2mm; capillary (second vessel)2with an average radius of 2.610-3mm has a length in the model 7,210-1mm; third segment to3connecting two capillary with an average radius of 3.810-3mm and a length of 2.410-1mm, the fourth vessel to4after merging MicroSCADA with a new capillary has an average radius of 4.510-3mm at a length of 3.410-1mm Resistance at each of the sites described by the formula (Ivanov, K. P., Kislyakov Y. Y. Energy demand and oxygen supply to brain. L:. Science, S. 89):
where Rkthe resistance of the blood in microcode, PA/mm2;
hk- the ratio of the apparent viscosity of blood in microcode, PAhk=0,001(1,4+0,045rk), (2)
where rkin this formula is given in microns. Thus, the coefficient of viscosity in the first plot is 1,5610-3Ns/m2on the second - 1,5210-3Ns/m2third - 1,5710-3Ns/m2and on fourth - 1,610-3Ns/m2. Factors translate into mm RT.art./m2(which multiply their 133).
The total resistance R in the course of successive microvessels having a resistance Riis:
Hence, the volumetric rate of blood circulation in the system of the microvascular1...to4will be (George C. I. Physiology of agriculture shall - the pressure gradient between the arterial and venous ends of the microvessels (Part-Rveins)=35-20=15 mm RT.article Thus, the volumetric rate of blood flow in the terminal area of the system considered parallel vessels (section K2) is 2.8610-5mm3/s
Volumetric blood flow velocity W in the first microcode equal to the sum of the volumetric velocity emerging from it microvessels. In merging the microvasculature of the volumetric rate of flow is equal to the sum of the merging of the microvasculature. Thus, in microvessels, which is not a terminal, the volumetric rate of flow will be described as follows:
where Wivolumetric blood flow velocity in each of the considered terminal capillaries,
k - the number of merges or splits into the area of the capillaries.
In our model, these areas were considered separately between zones two newly formed microvessels or merging microvessels. If the ends of the capillaries do not fall within the considered reconstruction, according to the data given in (Ivanov, K. P., Kislyakov Y. Y. Energy demand and oxygen supply of the brain ub>', (6)
where W2volumetric blood flow velocity in the formula (4), W1was 5,8810-5mm3/c.
W2'is the volumetric rate of flow in the system microvessels formed by the vessel To a2'.
where W2"is the volumetric rate of flow in the system microvessels formed To2". W3=6,2510-5mm3/s
where W2"is the volumetric rate of flow in the system microvessels formed To2". W4=9,5810-5mm3/s
The linear speed in the second microvessels calculated by the formula (George C. I. Physiology of farm animals. M: Agropromizdat, S. 219):
Thus, the linear blood flow velocity was V1=1,53 mm/s, V2=1,34 mm/s, V3=1,38 mm/s, V4=1,51 mm/s
The volumetric rate of flow in General accordance with the proposed spatial reconstruction $ 1.6910-4mm3/s, and the specific volume flow 8,4410-3mm3/(mm3), which is consistent with data which tell the brain. L:. Science, S. 83) and more boundary values, so changes in the hemodynamics of the brain is not installed.
Because the found linear blood flow velocity and specific volume blood flow velocity exceeds the cutoff value of 0.08 mm/s and 4.210-3mm3/(mm3), diagnosed that violations of blood circulation to the brain no (consider that in this local area blood supply to the brain is not broken).
Taken the dog is 2.8 years breed, weight 4,8 kg Dog introduced 30 mg of chlorpromazine, which was accompanied 80/25 mm RT.article Mean arterial pressure was 52,5 mm RT.article Do correlate to the average pressure, that is, to 80 mm RT.art., and we find that the level of systemic blood pressure below normal values 1.52 times. As a result, the pressure at the arteriolar end of the capillary divide 1.52 and get instead of 35 mm RT.article at the arterial end of the capillary in the norm metric, equal to 23 mm RT.article The pressure gradient between the parts of a model taking into account venous pressure of 20 mm RT.art., so, is 3 mm RT.article.
Taken as a model for motor nucleus of the trigeminal nerve nucleus is given a shape (spatial reconstruction) tie and vessels (see previous example) volumetric blood flow velocity will be W1=1,1410-5mm3/, W2=0,5710-5mm3/, W1=1,2510-5mm3/, W1=1,9210-5mm3/s
Linear velocity in these areas amounted to V1=0.35 mm/s, V2=0.25 mm/s, V3=0.28 mm/s, V4=0.30 mm/s
Specific volumetric blood flow velocity in the structure of the brain is 1,6910-3mm3/mm3).
Thus, the linear velocity of blood flow in microvessels low, but sufficient to prevent stasis and specific volumetric blood flow velocity significantly lower than normal. This correlates with the fact that at the time of the study pressure the dog was in a state of oppression functions of the Central nervous system (stupor - “oglushennosti”). At the end of the preparation condition of the animal recovered without changes in the nervous system, suggesting reversibility of impaired blood flow.
Taken the dog 3,4 years breed, weight 5,7 kg Dog intravenous introduced Isobaric, which was accompanied by a decrease in blood pressure to 70/25 mm RT.article Mean arterial pressure was the same averages in 1,684 times. As a result, the pressure at the arteriolar end of the capillary divide by the corresponding amount and received instead of 35 mm RT.article at the arterial end of the capillary at the normal rate equal 20,78 mm RT.article The pressure gradient between the two parts of the model obtained within 0,78 mm RT.article.
Taken as a model for motor nucleus of the trigeminal nerve nucleus shows a drawing (spatial reconstruction) in connection with similar body weight and age of the animal, obtained from dogs in the first example. As a result of calculations in similar areas considered parallel vessels (example 1) volumetric blood flow velocity will be W1=0,30610-5mm3/, W2=0,14910-5mm3/, W1=0,32510-5mm3/, W1=0,49810-5mm3/s
Linear velocity in these areas amounted to V1=0,079 mm/s, V2=0,070 mm/s, V3=0,072 mm/s, V4=0,079 mm/s
Specific volumetric rate of blood flow in the brain's structure is equal to 0.4410-3mm3/mm3).
Thus, the linear velocity of blood flow is decreased to the lowest rate Is related to in the time of the study pressure the dog was in a coma caused by a deep collapse. Animals were provided intensive resuscitation, but after its launch from a coma, the animal had evidence of diffuse disorders of the nervous system, suggesting a small damage to the nervous system caused by disturbances of the microcirculation.
Thus, this method allows to diagnose the circulation in the brain at the level of individual microbasins. The threshold level of change in linear velocity of less than 0.08 mm/s and a specific volume of blood flow velocity less than 4.210-3mm3/(mm3) is the boundary of circulatory disorders, leading to reversible or irreversible brain disorders.
As a result, the method allows to predict the degree of circulatory disorders in the local areas of the brain at the level of individual microvessels.
A method for the diagnosis of blood supply to the brain tissues, including determination of the number of microvessels and the total volume of the investigated area, characterized in that in the studied uh vessels, the blood volume in the study area, calculate linear and volumetric blood flow velocity in the separate parts of microvessels, General and specific volume of blood flow velocity, the linear velocity of blood flow in each of microvessels by formulas Century I. George, and the coefficient of viscosity is chosen separately for each MicroSCADA depending on its radius and decreasing the linear velocity of blood flow is less than 0.08 mm/s and a specific volume of blood flow velocity less than 4.210-3mm3/(mm3) diagnose circulatory disorders of the brain in this local area.
SUBSTANCE: method involves recording heart beat rate and systolic arterial blood pressure before and after two-stage exercise stress. The first stage is of 50 W within 3 min and the second one is of 75 W during 2 min. Patient rest pause is available between loading stages to recover initial heart beat rate. Prognostic estimation of cardiopulmonary complications is carried out with mathematical formula applied.
EFFECT: reduced risk of complications in performing tests.