CN1192351A - Instrument for quick measuring blood viscosity - Google Patents

Abstract

A blood viscosity quick measuring apparatus is composed of needle, conduct, barometric pump micro pressure senser and microcomputer. Under the control of microcomputer, the barometric pump extracts a little amount of blood from the vein of human body through the needle and conduct; the micropressure sensor measures the blood pressure at the two ends of the needle, which passes through preamplifier and A/D converter and enters the micro computer; and then with the support of software, the microcomputer computes the pressure difference across the needle and flow of blood, so that the apparent blood viscosity can be calculated.

Description

Instrument for quick measuring blood viscosity

The present invention relates to a kind of instrument of under physiological status, measuring the apparent blood viscosity of human body fast in real time.

Mobile blood is human life activity's symbol.Human body has only the blood flow state that keeps good, just can keep normal physiological function of organism and defense function, and human internal organ organizing ability obtains normal blood perfusion, thereby guarantees oxygen and the normal supply of nutrient substance and the timely discharging of metabolite.Normal blood flow state also depends on the rheological equationm of state of blood itself or the viscosity of blood except closely related with the function of heart and blood vessel.If the viscosity of blood flow occurs unusual, then can directly have influence on the blood perfusion of organs and tissues, make organs and tissues hypoxic-ischemic, Metabolic disorder, obstacle appears in function, thereby causes a series of serious consequences.Modern medicine is verified, hypertension, apoplexy, myocardial infarction, thromboangiitis obliterans, high altitude heart disease, pulmonary heart disease, preeclampsia, congenital heart disease and a series of hematopathy, especially high cardiovascular and cerebrovascular disease of fatality rate and disability rate and malignant tumor etc., its generation and development all are accompanied by the unusual of hemorheology character.Therefore, accurately measure the viscosity of blood, the particularly accurate blood viscosity of measuring under the different shear rates, the diagnosis and the treatment that not only can be some disease provide foundation, also have great significance for the generation of some disease of pathogeny, prediction and prevention (particularly cardiovascular and cerebrovascular disease) of some disease of research.

The instrument that is used to measure human blood viscosity in the prior art has polytype, as rotating cylinder viscometer, capillary viscosimeter, falling sphere viscometer, translation and crossing current viscometer etc.Though the blood viscometer structure of above-mentioned these types is different, measuring principle also is not quite similar, and but has a common characteristic, promptly all be to collect blood of human body external and add anticoagulant to measure as a kind of simple industrial fluids later.Such measuring method is measuring period long (generally needing 1-2 days) not only, and be subjected to inevitably taking a blood sample and measuring process in the influence of various extraneous factors, the length of for example adding of Cai Xue speed, anticoagulant, blood sample waiting time and the height of storage temperature, and measure temperature controlling etc.Because the influence of these factors not only can make the accuracy rate of blood viscosity measurement result reduce greatly, and can make measurement result not possess horizontal comparability.

Purpose of the present invention promptly is to obtain a kind of instrument of measuring human body bloodviscosity under the different shear rates under physiological status fast in real time, reducing the influence that extraneous factor is measured human blood viscosity to greatest extent, thereby improve the accuracy that blood viscosity measures and make measurement result have horizontal comparability.

To achieve these goals, the present invention utilizes syringe needle, conduit, pulsometer, micro-pressure sensor and microcomputer to form an instrument for quick measuring blood viscosity.Pulsometer extracts small amounts of blood by syringe needle and conduit from human vein under control of microcomputer, utilize micro-pressure sensor to measure the blood sample pressure at syringe needle two ends in blood drawing and row's blood process subsequently.The output of micro-pressure sensor is read in microcomputer after preposition amplification and A/D conversion, microcomputer calculates the blood sample pressure differential and the blood flow at syringe needle two ends in blood drawing and the row's blood process under the support of software, utilize the calibrating parameters (length and internal diameter) of syringe needle to calculate the apparent blood viscosity under each shear rate and be depicted as the blood viscosity curve by non-Newtonian fluid model viscosity formula again.Be described in further detail below in conjunction with the technical characterictic of specific embodiment instrument for quick measuring blood viscosity of the present invention.

Accompanying drawing 1 is the sketch map of instrument for quick measuring blood viscosity of the present invention.

With reference to the accompanying drawings 1, instrument for quick measuring blood viscosity of the present invention mainly is made up of syringe needle, conduit, pulsometer, micro-pressure sensor and microcomputer.

Syringe needle 1 is to cooperate pulsometer and conduit to extract the utensil of blood from human vein, is again the blood viscosity measuring cell simultaneously.During blood drawing, the front end level of syringe needle is inserted in the human vein blood vessel, and its rear end then is communicated with pulsometer byconduit 2 and electromagnetic valve 3.As measuring cell, the length L of syringe needle and internal diameter R can adopt conventional method to be demarcated.Result of calculation shows that L and R are respectively about 40mm He about 0.15mm can satisfy laminar flow condition and run-up condition.

Conduit 2 can adopt silica gel tube, and as the gas circuit of pulsometer, the blood device is stored up in conduct again on the other hand on the one hand for it.Theoretically, blood flows in conduit and can cause blood pressure to fall and cause measurement error.But result of calculation shows that its actual influence is little by 0.5%, so can ignore.Like this, the force value that measures of micro-pressure sensor just can be considered as the blood sample force value of syringe needle 1 rear end.The micro-pressure sensor 4 that is used for measuring syringe needle two ends blood sample pressure is installed in theconduit 2 before the electromagnetic valve 3, and its range and certainty of measurement are decided by the excursion of blood flow in the measuring process and shear rate.Statistics shows, people's blood viscosity only at shear rate less than 200s^-1The time just meaningful, especially shear rate is less than 80s^-1The time, the characteristics of the non-Newtonian fluid of blood are obvious gradually.Therefore, when measuring the human body blood viscosity, the coverage of shear rate may be selected to be 20-200s^-1In this scope, the excursion of human body blood viscosity is 4.95～12.65cp.If temporarily blood of human body is considered as Newtonian fluid, then corresponding pressure range is Δ P_Min=53pa.In view of the above, the range of micro-pressure sensor 4 is chosen as 5kpa, and its precision is chosen as 1 ‰.Because the output that is easy to reach capacity that range is the micro-pressure sensor of 5kpa, and also cause the damage of micro-pressure sensor easily when overstepping the extreme limit pressure, be that themicro-pressure sensor 5 of 100kpa is monitored the pressure in the piston cylinder so after electromagnetic valve 3, set up a range again.

Microcomputer in this measuring instrument can adopt IBM PC and compatible family microcomputer, and the A/D change-over panel can adopt with the bus compatible HT-1232A/D change-over panel of IBM PC XT/AT and directly insert in the microcomputer expansion slot.This A/D change-over panel has 32 tunnel single-ended analog input channels, and this measuring instrument uses two paths wherein, connects micro-pressure sensor 4 andmicro-pressure sensor 5 respectively and adopts the software gating.Because the flow velocity of blood is very little in the measuring process, every interval is the ability once sampling about 1 second, so transfer of data can adopt inquiry mode.

Pulsometer can have multiple pattern, for example can constitute a kind of piston-type pressure pump by piston and piston cylinder and leading screw, motor and piston stroke switch.Microcomputer rotates forward or backwards by I/O card control motor, and motor shaft can makepiston 7 move back and forth in piston cylinder 8 to change the air pressure in the piston cylinder by leading screw 6 after slowing down.The piston stroke switch can adopt photoswitch, the photoelectric yield ofphotoswitch 9 andphotoswitch 10 is by I/O card input microcomputer, the bottom ofpiston 7 has the dark slide 11 of working in coordination withphotoswitch 9 andphotoswitch 10, and the top of piston cylinder 8 is communicated withconduit 2 and atmosphere respectively by electromagnetic valve 3 andelectromagnetic valve 12.

The process of utilizing this measuring instrument to measure the human body blood viscosity mainly comprises with individual step:

1, resets: close electromagnetic valve 3, openelectromagnetic valve 12, makepiston 7 move to the top of piston cylinder 8, and then closeelectromagnetic valve 12.

2, cause negative pressure: makepiston 7 to the motion of piston cylinder 8 bottoms, make and cause certain negative pressure P in the piston cylinder 8₀(bymicro-pressure sensor 5 monitoring and with microcomputer in set negative pressure value and compare), this moment, the volume of piston cylinder was V₀

3, blood drawing: syringe needle 1 level is inserted in the human vein, opened electromagnetic valve 4.Under the effect of negative pressure, blood will be in the slow inflow catheter of syringe needle.In this process, utilize micro-pressure sensor 4 to sample, sampled result deposits microcomputer in.Theoretically, sampled value should increase gradually, and we define a value, when the difference that continuous 3 sampled values occur is worth less than this, stops sampling.The fluctuation that human vein is pressed is very little, particularly can think certain value under the hemostatic situation.At the end of blood drawing process, when micro-pressure sensor 4 detected force value no longer change, can think that the pressure in venous pressure and the piston cylinder has reached balance, the micro-pressure sensor measured value of this moment promptly equals venous pressure.

4, cause malleation: close electromagnetic valve 4, openelectromagnetic valve 12 and makepiston 7 move to the bottom of piston cylinder 8, closeelectromagnetic valve 12 then and makepiston 7, in piston cylinder 8, to cause certain malleation P to piston cylinder 8 tip motions₀' (bymicro-pressure sensor 5 monitoring and with microcomputer in set the malleation value and compare), this moment, the volume of piston cylinder was V₀'.

5, row's blood: extract syringe needle 1 and openelectromagnetic valve 5, under the effect of malleation, the blood that is stored in theconduit 2 will be discharged by syringe needle 1.In the process of row's blood, utilize micro-pressure sensor 4 to sample, sampled result deposits microcomputer in.In row's blood process, the pressure of syringe needle 1 front end is atmospheric pressure.

The key of utilizing this measuring instrument to measure human blood viscosity is to detect by the syringe needle blood drawing and arranges the blood sample pressure at syringe needle two ends in the blood process and calculate blood sample pressure reduction and corresponding blood flow, and the calculating of blood sample pressure reduction and corresponding blood flow is to utilize blood sample force samples value to finish under the support of software by microcomputer.Under the situation of blood drawing, blood sample pressure reduction is the poor of sampled value and venous pressure, and corresponding blood flow then can and utilize P by the isotherm compression equation of gaseous state₀, V₀Calculate with sampling time interval.Under the situation of row's blood, blood sample pressure reduction is the poor of sampled value and atmospheric pressure, and corresponding blood flow then can and utilize P by the isotherm compression equation of gaseous state₀', V₀' and sampling time interval calculating.Calculate after the blood sample pressure reduction and corresponding blood flow at syringe needle two ends, microcomputer can calculate the apparent blood viscosity under the different shear rates and be depicted as the blood viscosity curve by the viscosity formula of non-Newtonian fluid model.Blood of human body is a kind of non-Newtonian fluid, many studies show that, and it can be used as power law Model Fluid, Cusson law model fluid or Blngham plastic fluid and handles.

The present invention can measure the blood viscosity of human body under the different shear rates fast in real time under physiological status, can get rid of the influence that extraneous factor is measured human blood viscosity to greatest extent, thereby can significantly improve the accuracy of blood viscosity measurement and make measurement result have horizontal comparability.Therefore, the present invention is particularly suitable for the multimeter as the human body blood viscosity.

Claims (2)

1, a kind of instrument for quick measuring blood viscosity of under physiological status, measuring people's body surface sight blood viscosity under the different shear rates fast in real time, it is characterized in that by syringe needle, conduit, pulsometer, micro-pressure sensor and microcomputer are formed, pulsometer extracts small amounts of blood by syringe needle and conduit from human vein under control of microcomputer, in blood drawing and row's blood process subsequently, utilize micro-pressure sensor to measure the blood sample pressure at syringe needle two ends, the output of micro-pressure sensor is read in microcomputer after preposition amplification and A/D conversion, microcomputer calculates the blood sample pressure reduction and the blood flow at syringe needle two ends in blood drawing and the row's blood process under the support of software, the calibrating parameters that utilizes syringe needle again calculates the apparent blood viscosity under each shear rate and is depicted as the blood viscosity curve by the viscosity formula of non-Newtonian fluid model.

2, instrument for quick measuring blood viscosity according to claim 1 is characterized in that described pulsometer is the piston-type pressure pump that is made of piston, piston cylinder and leading screw, motor and piston stroke switch; Microcomputer rotates forward or backwards by I/O card control motor, and motor shaft can make piston move back and forth in piston cylinder by leading screw; The piston stroke switch is a photoswitch, and its photoelectric yield is by I/O card input microcomputer, and the lower end of piston has the dark slide of working in coordination with photoswitch; Piston cylinder is communicated with conduit and atmosphere respectively by electromagnetic valve.

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