RU2107456C1 - Method and system for measuring blood pressure in deep brachial vein - Google Patents

Abstract

FIELD: medicine; medical engineering. SUBSTANCE: method involves recording venous pulse signals emitted by vascular fascicle of brachial plexus under rising pressure in constricting measuring cuff. Contour analysis of the recorded pulsogram is carried out to select outermost points in its diastolic segment which projection upon linear increment plot of the applied pressure corresponds to values of diastolic, lateral and maximum pressure. Measurement system has compression device connected to measuring cuff, pneumatic-to-electric signal converter having scaling amplifier of permanent current. Amplified signals of current pressure values come to one of recorder channels, the second recorder channel receives pulsogram amplified by the scaling amplifier and formed by band-pass filter. EFFECT: non-invasive measurement of pressure in brachial vein. 2 cl, 2 dwg

Description

 The invention relates to medicine, in particular to physiology and cardiology, can be used both in clinical practice and in experimental studies.

 A known method of direct measurement of pressure in the veins of the shoulder. (See, for example, Waldman VA "Venous pressure and venous tone", Medgiz, Leningrad, 1974, p. 34-43). This method is based on the introduction of a needle or catheter into the brachial vein, a water gauge is connected to the catheter with a rubber tube, which measures the average venous pressure in the specified vein. At present, the principle of measuring venous pressure by the direct method has not practically changed; only recording measuring systems have been changed.

 A direct method for measuring venous pressure is traumatic and not always safe for the subject.

 Known indirect plethysmographic method for measuring pressure in the veins of the shoulder, based on an increase in the volume of the distal portion of the arm of the patient being examined in response to the created occlusion of the brachial veins. (See, for example, T. N. Proklova et al. Study of Vein Extensibility in Patients with Hypertension, Cardiology, 1985, N 1 Moscow, pp. 54-57). This method is carried out as follows. The examined patient, who is in a horizontal position, is put on a shoulder with a pinch measuring cuff placed on the shoulder and raised 10 cm below the level of the anterior chest wall, and a mercury-rubber sensor is installed around the perimeter of the forearm of the same arm. Slowly increase the pressure in the pneumatic cuff to about 7-10 mm Hg. and mark the beginning of an increase in the volume of the forearm, considering this moment an indicator of venous pressure.

 The publication does not indicate in which vein pressure is measured and what magnitude of venous pressure is determined, but we can conclude that this is only one indicator, the knowledge of which is clearly insufficient to determine the state of the venous part of the circulatory system.

 The aim of the invention is to provide a method for measuring pressure in the deep vein of the shoulder and a measuring system for its implementation, which would provide an atraumatic and reliable measurement of venous pressure.

 This goal is achieved by the fact that the method of determining pressure in the deep veins of the shoulder using the measuring system according to the invention is that a pinch measuring cuff is applied to the vascular bundle of the patient’s shoulder and, in the process of increasing pressure, the latter records a graph of the linear increase in applied pressure and a pulsating waveform blood flow in the form of a venous arterial pulsogram having a diastolic and systolic region and representing a sequence of waves in venous pulse, reflecting the change in the volume of the lobed vascular bundle of the shoulder over time under the influence of increasing pressure in the pinch measuring cuff, after which extreme points are drawn in the recorded oscillogram, which is a venous-arterial pulsogram, through which straight lines are drawn until they intersect, and the intersection points of these lines are projected onto a graph of a linear increase in the applied pressure, and the ordinates of these points are indicators of pressure in deep vein of the shoulder.

 This makes it possible for the first time to obtain atraumatic and reliable measurements of venous pressure.

It is advisable to register the venous-arterial pulsogram with the horizontal position of the patient being examined, when his venous pressure in the deep vein of the shoulder is higher than atmospheric. The arm of the patient being examined at this moment should be pulled away from the vertical axis of the body by about 70 ^o , which virtually eliminates the possibility of squeezing the vein in the section from the subclavian vein to the deep vein of the shoulder, does not interfere with the transmission of venous waves of blood flow from the right heart and promotes the formation of venous arterial pulsogram.

 To increase the accuracy of determining the pressure indices in the deep vein of the shoulder when analyzing the venous-arterial pulsogram, it is rational to record the latter in the pressure range from about 0 to about 60 mm Hg. Art. in pinch measuring cuff for approximately 40 s.

 This goal is also achieved by the fact that the measuring system for determining pressure in the deep vein of the shoulder contains sequentially interconnected compression device that provides a linear increase in pressure in the pinch measuring cuff, having a device for controlling the calibrated value of the applied pressure; a converter of pneumatic pressure signals taken from the specified pinch measuring cuff into electrical signals, the input of which is connected to the output of the compression device and pinch measuring cuff; a scaling amplifier, the input of which is connected to the output of said pneumatic signal converter; a recorder designed to record the oscillogram of a pulsating blood flow in the form of a venous arterial pulsogram and having at least two channels, one of which is connected to the output of a bandpass filter, according to the invention, this bandpass filter, the input of which is connected to the output of a scaling amplifier of electrical signals, has a linear amplitude conversion characteristic and a linear amplitude-frequency characteristic in the frequency range from about 0.5 to 50 Hz and is intended for venous - an arterial pulsogram from volumetric signals of the venous pulse taken from the pinch measuring cuff during the increasing pressure in the latter, and it also contains an additional scaling DC amplifier of signals of the current pressure values in the pinch measuring cuff, the input of which is connected to the output of the pneumatic signal converter, and output to the input of the second channel of the registrar.

 In FIG. 1 shows a venous-arterial pulsogram recorded from the deep vein of the shoulder of the patient being examined and a graph of increasing pressure in the pinch measuring cuff according to the invention; in FIG. 2 is a block diagram of one embodiment of a measuring system for determining pressure in a deep vein of a shoulder of an examined patient.

 Before starting the measurement of pressure in the deep vein of the shoulder of the patient being examined, calibration of graph 1 of the increasing pressure shown in FIG. 1 in the pinch measuring cuff 2 (Fig. 2) by pulse 3 (Fig. 1), the value of which is equal to the known absolute value of the pressure in the cuff 2 in mm RT. Art. (In this case, the pulse 3 (Fig. 1) of the calibration signal corresponds to the pressure in the measuring system = 50 ml of mercury.).

 Slowly, according to the linear law, the pressure is increased, as shown in graph 1 in the pinch measuring cuff 2 (Fig. 2), volume signals 4 (Fig. 1) of the venous pulse arising under the action of a pulsating blood flow in the vascular bundle of the shoulder are recorded. With the values of atmospheric venous pressure in the examined patient, the signals 4 (Fig. 1) of the venous pulse perceived by cuff 2 (Fig. 1) are formed, which are formed under the action of increasing pressure according to graph 1 (Fig. 1) in cuff 2 (Fig. 2) in the waveform , which is a venous-arterial pulsogram 5 (Fig. 1), which undergoes a series of changes during the registration cycle that carry information about the pressure in the deep veins of the shoulder of the patient being examined.

The formation of the venous-arterial pulsogram 5 (Fig. 1) begins with the beginning of a linear increase in pressure according to graph 1 in pinch measuring cuff 2 (Fig. 2). A pulsating blood tray, perceived by the cuff 2 from the vascular bundle of the shoulder of the patient being examined, is recorded as volumetric signals 4 (Fig. 1) of the venous pulse. At the beginning of the increase in pressure in the cuff 2 (Fig. 2), the signals 4 (Fig. 1) of the venous pulse increase somewhat due to the compression of the arm of the patient being examined by the cuff 2 (Fig. 2). After reaching pressure according to schedule 1 in cuff 2 (Fig. 2) of the minimum venous pressure Pb _min in the deep vein of the patient’s shoulder, the amplitudes of the signals of 4 venous pulses begin to increase intensively due to a change in the volume of veins under the action of increasing pressure according to schedule 1 (Fig. 1) in the cuff 2 (Fig. 2). This increase in time continues until pressure is reached according to graph 1 (Fig. 1) in cuff 2 (Fig. 2), which is equal to the average pressure in the deep vein of the shoulder Pb _cf , and then to pressure 1 (Fig. 1), equal to lateral pressure PB _side, deep vein amplitude patient shoulder 4 venous pulse signals remain substantially unchanged. Further, with an increase in pressure according to schedule 1 (Fig. 1) in the cuff 2 (Fig. 2) from the lateral pressure Рв _side to the maximum pressure Рв _max in the deep vein of the patient’s shoulder, the amplitude of the signals 4 (Fig. 1) of the venous pulse decreases and when pressure is reached according to schedule 1 (Fig. 1) in the cuff 2 (Fig. 2) of the maximum pressure Pv _max in the deep vein of the shoulder, the located vein closes, and the signals 4 (Fig. 1) of the venous pulse on the venous arterial pulsogram 5 (Fig. 1) are transformed in the waveform of signals 6 (Fig. 1) of the arterial pulse.

 In FIG. 1 shows the basic principles for determining venous pressure indicators on a venous-arterial pulsogram 5. Subject to the requirement of a linear increase in pressure according to graph 1 (Fig. 1) in pinch measuring cuff 2 (Fig. 2), all extreme points of signals 4 of venous pulse in systolic and diastolic areas on venous arterial pulsogram 5 lie on straight lines of LK; KM; MN; NO; OP and AB; BC; CD DE; EF respectively. The largest change in the amplitude ratios of the signals 4 of the venous pulse on the venous-arterial pulsogram 5 occurs in the diastolic region bounded by straight lines AB; BC; CD DE and EF, EF are already in the waveform region of signals 6 (Fig. 1) of the arterial pulse.

 Objectively, venous pressure indices are determined after tracing the extreme points of the signals of 4 venous pulses in the diastolic region from left to right by the indicated straight lines AB; BC; CD DE and with and after their transformation into signals of 6 arterial pulses by the EF line.

 Points B: C: D: E of the intersection of these lines are indicators of venous pressure in the deep vein of the shoulder: B - minimum; C - medium; D - lateral and E - maximum pressure.

 The found points B: C: D: E of the venous pressure indicators are projected onto graph 1 of the increasing pressure in the pinch measuring cuff 2 (Fig. 2), at points b; c; d; e projections of the specified graph 1 (Fig. 1) pressure measure the absolute value of pressure in the deep vein of the shoulder of the patient being examined.

 In some cases, to determine the pressure in the deep vein of the shoulder (most often in the presence of strong respiratory waves) by straight lines LK; KM; MN; NO and OP also circle the systolic region of the venous arterial pulsogram 5 and at points K; L; M; N of their intersection find further information about their whereabouts.

 Below is described one of the embodiments of the measuring system for measuring pressure in the deep vein of the shoulder, carried out according to the claimed method.

 The main requirement for a measuring system for registering a venous-arterial pulsogram 5 is the requirement for the linearity of its amplitude-frequency characteristics throughout the path of conversion, amplification and registration of signals 4 of the venous pulse under the influence of increasing pressure according to schedule 1 (Fig. 1) in pinch measuring cuff 2 At the same time, its amplitude-frequency characteristic should be rectilinear horizontal in the frequency range from about 0.5 to 50 Hz, which allows you to register venous arteries cial pulsogram 5 (FIG. 1) with minimum distortion associated with minor movements and respiratory waves of the subject patient.

 Another important requirement for the aforementioned measuring system is a linear characteristic of the conversion of signals 4 of the venous pulse throughout the path of conversion, amplification and registration in the entire range of changes in the amplitudes of the venous-arterial pulsogram 5.

 In a measuring system designed to implement the method for determining venous pressure in the deep veins of the shoulder, it is advisable to increase the linear pressure set according to graph 1 (Fig. 1) in pinch measuring cuff 2 (Fig. 2) from approximately 0 to 60 mmHg. Art. for about 40 s.

 A block diagram of one embodiment of a measuring system for implementing the described method is shown in FIG. 2.

 The measuring system for recording the venous-arterial pulsogram 5 (Fig. 1) contains sequentially interconnected compression device 7 (Fig. 2), equipped with a system (not shown in Fig. 2) for calibrating and controlling the set and pressure relief in the pinch measuring cuff 2; converter 8 pneumatic signals into electric, the first scaled amplifier 9 of the signals 4 (Fig. 1) of the venous pulse and the second scaled amplifier 10 (Fig. 2) of the signals of the current values of increasing pressure according to schedule 1 (Fig. 1) in the cuff 2 (Fig. 2) ), a band-pass filter 11 of signals 4 (Fig. 1) of the venous pulse of the venous-arterial pulsogram 5 and at least a two-channel recorder 12 (Fig. 2).

 The proposed measuring system uses a standard pinch cuff 2. As a compression device 7, one of the widely known microcompressors can be used. The pressure increase mode according to schedule 1 (Fig. 1) in cuff 2 (Fig. 2) can be carried out directly from such a microcompressor, or by pre-pumping the receiver (not shown in Fig. 2 to a pressure whose value exceeds approximately 2-3 times the maximum the pressure in the deep vein of the shoulder of the patient being examined, and then compress the cuff 2. In this case, the pressure set 1 (Fig. 1) in the cuff 2 (Fig. 2) will be almost linear. The operation of the microcompressor should not cause pneumatic and electrical interference to signals 4 ( Fig. 1) veins znogo pulse signals 6 and arterial pulse, removed from the cuff 2 (FIG. 2).

 With the beginning of the pressure measurement cycle in the deep vein of the shoulder of the patient being examined, the signals of increasing pressure according to the graph 1 (Fig. 1) and pneumatic volume signals of the pulsating blood flow in the vascular are perceived by the cuff 2 (Fig. 2) to the pressure transducer 8 of the measuring system the shoulder beam of the patient being examined, where they are converted into electrical signals 4 (Fig. 1) of the venous pulse and signals of the current values of increasing pressure according to graph 1 (Fig. 1) in the cuff 2 (Fig. 2). These signals are amplified separately on two channels by their scaled amplifiers 9 and 10. The signals of the current values of the increasing pressure according to graph 1 (Fig. 1) in pinch measuring cuff 2 (Fig. 2) are sent immediately to one of the channels of recorder 12, and signals 4 (Fig. 1), the venous pulse first passes through a band-pass filter 11 (Fig. 2) and only then is fed to the second channel of the recorder 12. It is advisable to record the signals in rectangular coordinates, for example, on a Siemens-Elema well-known mingograph or on a personal computer a yuter. As a result of one measurement cycle, the venous-arterial pulsogram 5 is recorded on the recorder 12 and synchronously with it the current values of the pressure value according to graph 1 (Fig. 1) in the pinch measuring cuff 2 (Fig. 2), which are further analyzed.

Example. In FIG. 1 examined patient at the age of 35 years old was lying with his arm folded back approximately 85 ^o , on which a standard measuring pinch cuff 2 was applied. Before registration, the measuring channel of increasing pressure according to schedule 1 was calibrated by a rectangular pulse 3, equal to 50 mm Hg. Art. After that, the compression device 7 (Fig. 2) was turned on, which slowly increased the pressure according to schedule 1 (Fig. 1), in the pinch measuring cuff 2 (Fig. 2) and from the signals 4 (Fig. 1) of the venous pulse with an increase in the indicated pressure 1, a venous-arterial pulsogram was formed 5. Next, we proceed to the analysis of the registered venous-arterial pulsogram 5. From left to right in the diastolic region of the venous-arterial pulsogram 5, extreme points are selected on the signals of 4 venous pulses, circled them, approximating by straight lines E AB; DC CD DE and EF. Points B; C; D; E intersections of these lines are, respectively, indicators of the minimum venous pressure Pb _min ; average venous pressure Rv _cf ; lateral venous pressure Rv _side and maximum venous pressure Rv _max in the deep vein of the shoulder. Points B; C; D; E project on the graph of the current values of the ramp pressure 1 and at points b; c; d; e of their projections measure the absolute values of the above pressures in the deep vein of the shoulder. So, in the patient being examined, taking into account the calibration of the increasing pressure according to graph 1, where each linear mm vertically is equal to the pressure of 2 mm Hg, the values of venous pressure in the deep vein of the shoulder are equal: the minimum venous pressure Pb _min = 4 mm Hg .; average venous pressure Rv _cf = 6 mm Hg; lateral venous pressure Rv _side = 9 mm Hg; maximum venous pressure Rv _max = 12 mm Hg

 Thanks to the patented method for measuring pressure in the deep vein of the shoulder and a measuring system for its implementation, it was possible to measure all pressure indicators in the deep vein of the shoulder in a non-invasive way.

 As indicators of pressure values in the deep vein of the shoulder, regular physiological processes are used that take place in a living organism and lead to the formation of the contour of the oscillometric curve, the inflection points of which appear as a result of two oppositely directed along the sign of pressure; intravascular pressure and pressure from the measuring pinch cuff, on the basis of which the measurements are very accurate.

 The simplicity of taking all pressure indicators in the deep vein of the shoulder with just one cuff applied to the located portion of the vascular bundle of the shoulder of the limb of the patient makes it possible to attract unskilled medical personnel for examination or to be examined by the patient himself.

 The measuring system for implementing the proposed method for measuring pressure in the deep vein of the shoulder of the patient being examined is quite simple and consists of blocks that are known and widely used in medical technology.

 Currently, medicine does not have simple and reliable indirect methods for obtaining indicators of the state of venous circulation in various types of human diseases and their relationship with other indicators of blood circulation.

 The invention makes this possible for the first time.

 The patented method will expand the understanding of the nature of the diseases of the examined patients, select drugs individually for each of them, and take preventive measures in time.

 In addition, the venous-arterial pulsogram of almost every examined patient is individual in character, and can be used as a characteristic of the state of his individual circulatory system.

 The shape of the venous-arterial pulsogram allows you to automate the processing of measurement data of pressure indicators in the deep vein of the patient being examined.

 In addition, the measuring system for implementing the patented method is quite simple, it uses the well-known and affordable mechanical, pneumatic and electronic components used to measure blood pressure in modern equipment.

 The application of the proposed method for determining the hemodynamic parameters of the venous part of the circulatory system and the measuring system for its implementation in the healthcare system can greatly simplify and speed up the examination of a wide range of people, significantly increasing the reliability and amount of information received. The method can be the basis of a whole complex of equipment designed for non-invasive examination in patients not only of venous pressure in the vessels of the shoulder, but also of the circulatory system as a whole.

Claims (2)

 1. The method of determining the pressure in the veins of the shoulder, which consists in the fact that the patient is in a horizontal position on the vascular bundle of the shoulder impose a pinch measuring cuff and increase the pressure in it, characterized in that in the process of increasing pressure in the pinch measuring cuff from 0 to 60 mmHg register a graph (1) of a linear increase in the applied pressure and a venous-arterial pulsogram, in the diastolic region of which (ABCDEF) extreme points (A, B, CD, E, F) are distinguished through which straight lines (AB, BC, CD, DE , EF) until they intersect, then the intersection points (B, C, D, E) of these lines are projected onto the graph (1) of the linear increase in the applied pressure, and their ordinates (a, b, c, d) are absolute values of the diastolic pressure, respectively , medium pressure, lateral pressure and maximum pressure in the veins of the shoulder.  2. A measuring system for determining the pressure in the veins of the shoulder, containing a compression device (7) connected in series with each other, connected to a pinch measuring cuff (2), a converter (8) of pneumatic pressure signals into electrical signals, a scaling amplifier (9), a bandpass filter (11) and a recorder (12), characterized in that it contains an additional scaling DC amplifier (10), the input of which is connected to the output of the pneumatic signal converter (8), and the output to the second channel p recorder of (12), wherein the bandpass filter (11) has a bandwidth of about 0.5 to 50 Hz.

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