RU2150879C1 - Disposable capillary syringe-viscosimeter for investigation of biological liquids - Google Patents

Abstract

FIELD: medicine, in particular, biological liquid viscosity measuring equipment. SUBSTANCE: syringe has transparent cylindrical casing with branch pipe for seating and fixing of needle on outlet end of casing, and piston. Casing rim with opening in its side wall is positioned in axial alignment with casing and may be rotated so that its opening is aligned with drain opening in casing or in overlapped relation with respect to casing opening. Indicator-sight is positioned on bar joined to piston stem. Straight cylindrical capillary is positioned in outlet part of casing, and drain opening in side wall is adapted for communicating cavity under piston with atmosphere. Syringe of such construction allows viscosity of biological liquid to be easily measured even by unskilled people. EFFECT: increased efficiency, simplified construction and convenient usage. 5 dwg

Description

 The invention relates to medical equipment, in particular to syringes (IPC A 61 B 5/00, A 61 M 5/178). At the same time, it relates to means for measuring the viscosity of liquids (IPC G 01 N 11/06).

State of the art
Known medical injection interchangeable collapsible syringe with a capacity of 2.0 ml, reusable, which was produced in large quantities by the Mozhaisk Medical Instrument Plant (143220, Moscow Region, Mozhaisk, MIZ named after V.P. Guseknov) in accordance with TU 64-1 -789-83.

 The syringe consists of a transparent glass cylinder with a measuring scale applied to the side surface and with a tip for attaching the injection needle, as well as a piston with a rod and handle.

 The syringe is intended for repeated use, however, this method does not guarantee 100% reliable sterilization after contact with infected patients. This is especially true for viral lesions (HIV infection, viral hepatitis, etc.).

 Known disposable plastic medical syringe with a capacity of 1.0 ml for injection of insulin, commercially available in Russia and produced in the Republic of Korea ("Disposable syringe", BU QUANG MEDICAL INC., C. P. Box 8647, Seoul, R. Korea, fax: 82-2-888-80 16).

 A one-time use of this product involves infectious safety.

 Both types of syringes, as well as other medical syringes, allow you to measure the volume of liquid that is in the cavity of the cylinder, and do not allow you to measure other quantitative characteristics of liquids, in particular viscosity.

 Information on the viscosity of biological substrates is very valuable for doctors of many specialties. When applied to blood, it enters, as an integral part, into the concept of hemodynamic resistance, and the load on the heart depends on it. An increase in the viscosity of bile leads to a violation of its evacuation from the bile ducts and gall bladder. This, in turn, causes stagnation and provokes the formation of stones. An increase in sperm viscosity can cause male infertility. Etc.

 In addition to diagnostics, information on viscosity reflects the correctness and dynamics of the patient’s treatment, and its return to the “normal” range is a mandatory criterion for recovery.

 The relevance of obtaining information in this area is confirmed by the publication of specialized monographs and periodicals ("Blood Rheology", V. A. Levtov, S. A. Regirer, N.Kh. Shadrina, Moscow, "Medicine", 1982. "Rheological studies in medicine ", rheological society named after G.V. Vinogradov, collection of works, issue 1, compiled by E.V. Roitman, Moscow, 1997).

 The widespread use in medicine of information on the viscosity of biosubstrates is hindered by a number of factors. The main one is the lack of widely available, cheap, simple and easy-to-use equipment.

 Two main types of viscometers are known: rotational and capillary (monograph - “Blood Rheology”, V. A. Levtov, S. A. Regirer, N. Kh. Shadrina, Moscow, “Medicine”, 1982).

 Rotational viscometers allow you to work with good accuracy in a wide range of parameters. But they are very expensive and multi-element electronic devices. Reliable chemical sterilization of their measuring cells with the inevitable use of chemically active and aggressive solutions or vapors is difficult and unprofitable, and there is no need to talk about thermal or radiation sterilization.

 Capillary viscometers are much simpler and more common.

 Known capillary viscometer for the study of blood type VK-4, manufactured by the Poltava glass factory of the Minmedprom in accordance with MRTU-64-2-192-72. Its use is widely described in specialized products ("Guide to practical exercises in normal physiology", edited by G. I. Kasitsky and V. A. Polyantsev, Moscow, "Medicine", 1988).

 This device consists of two identical glass tubes having measured linear scales and capillary sections. The viscometer allows you to obtain data on the relative viscosity (compared with water). During the measurement process, water and the test liquid are drawn through the capillaries under the influence of the same pressure, and the ratio of the path lengths of the meniscus of the liquids reflects the ratio of viscosities.

 However, this viscometer is not disposable. Reliable sterilization is problematic due to the multicomponent and heterogeneous nature of the constituent elements: glass, steel, wood, rubber, glass crane parts connected by lubrication.

 Thus, the problem of the safety of measuring the viscosity of biological substrates in patients, virus carriers (HIV, hepatitis, etc.), or people suspected of these conditions is far from being resolved.

 It should be borne in mind that most of the medical instruments that come in contact with the blood and secretions of patients are currently being disposed of throughout the civilized world (gloves, scalpels, needles, catheters, etc.).

SUMMARY OF THE INVENTION
The task to which the claimed invention is directed is to create a device that, on the one hand, would refer to disposable medical instruments, and on the other hand, would allow for viscometry.

 The first requirement, (one-time use), implies cheapness, ease of operation, low-labor disposal, reliable initial disinfectability of the device and a small number of parts in it. Disposable medical syringes that are used universally meet all these requirements. Therefore, such a syringe is taken for the constructive basis of the proposed device.

 The second requirement - the possibility of viscometry, should be paired with the first.

 The inventive device meets these requirements. Structurally, it is made in the form of a disposable syringe containing a transparent cylindrical body with a pipe for putting on and fixing a needle at the output end, and a piston with the addition of four previously missing elements. This new collection allows you to measure the viscosity of liquids.

 The newly introduced elements include: 1 - a straight cylindrical capillary in the output part of the housing; 2 - a drainage hole in the lateral surface of the syringe barrel in the area of the socket for communication of the cavity of the piston space with the atmosphere; 3 - a bandage axially located in the form of a body rim with a hole in its side wall, mounted to rotate and align this hole with a drainage hole in the syringe body or overlap the drainage hole; 4 - pointer-sight, fixedly mounted on a rod mated to the piston rod.

 The device is based on the method of viscometry, which takes into account the time of expiration through the capillary of a given volume of fluid moving under the influence of constant pressure.

 In a conventional injection syringe, the solution moves under the pressure of the piston on the liquid when they are in direct contact, which is set by the hands of the operator. In this case, the volume of fluid and its flow rate can be taken into account and controlled. The magnitude of the pressure on the liquid is estimated only qualitatively, since there is no feedback information.

 In the proposed device in the measurement process between the liquid and the piston is air, the mass of which is constant and which acts as an elastic element. Before starting the measurement, it is compressed and remains compressed to a constant degree during the entire measurement. Thus, a constant pressure is achieved, under the influence of which the fluid flows through the capillary.

 Informing the operator about the degree of air compression in the syringe is determined by the presence of a newly introduced structural element, a pointer-sight, which is fixedly connected to the syringe rod by means of a rod and is located outside the cylinder, projecting onto a regular measuring scale of the syringe.

 Holding the pointer-sight on the meniscus of the fluid visible through the transparent walls of the syringe, the operator moves the piston at such a speed that the sight constantly coincides with the meniscus of the fluid. This leads to a constant degree of compression of the air.

 Obviously, the air pressure must be fixed and identical in all measurements. In addition to temperature and initial pressure in air, this depends on the number of gas molecules, i.e. from the mass of air, which should be constant. The latter is achieved by the fact that there is a drainage hole in the wall of the syringe per area filled with air. It can be closed with a bandage or open and communicate the atmosphere with the piston space of the syringe.

 The bandage is made in the form of a rim syringe axially located outside the body. It has a hole and can be rotated around the syringe barrel. Such rotation can combine the drainage hole in the syringe with the hole in the bandage, or hermetically close the drainage hole with the wall of the bandage and disconnect the atmosphere and the cavity of the syringe.

 The operation of the device.

 The measurement cycle consists of two stages.

 The first, preparatory, is to fill the syringe with the test fluid. By the beginning of filling, the drainage hole is closed, and the piston is shifted towards the capillary located in the outlet of the syringe. The piston is left in a position in which it does not reach the inner end of the capillary, and so on. a certain amount of air is enclosed in the syringe.

 Then, a needle is put on the syringe, the end of which is placed in the test liquid. Then, pulling the piston, they recruit it into the syringe. After collecting the required amount, which is taken into account on the meniscus of the liquid and the scale, the movement of the piston is stopped, and the needle is removed from the substrate.

 To temporarily prevent subsequent leakage of fluid from the syringe, it is transferred to a horizontal position or, instead of a needle, a sealing cap is put on the outlet pipe.

 After that, by turning the bandage, a drainage hole is opened, as a result of which the atmosphere communicates with the under-piston space, which is filled with air.

 Then the piston is put into the desired position, constant for all measurements, and the drainage hole is tightly closed with a bandage. The meniscus of the fluid remains unchanged.

 As a result of the actions taken, a predetermined volume of liquid is located in the syringe, which is separated from the piston by a fixed volume and amount of air, and the pointer-sight takes the position between the meniscus of the liquid and the piston.

 The cap from the outlet of the syringe, if used, is removed.

 Second phase. Actually measurement.

 The piston is intensively shifted towards the liquid until its meniscus and the sight pointer are aligned, i.e. due to air compression in the syringe, excessive pressure on the liquid is set. At the same time, note the time, for example, by a stopwatch. The fluid flows from the syringe cavity, and the meniscus is displaced. The operator moves the piston after the meniscus so that the pointer-sight is constantly projected onto the meniscus. This determines the constancy of the distance between the fluid and the piston, i.e. stability of excess pressure.

 After the meniscus reaches a pre-selected mark on the syringe scale, the time is noted and measurement is stopped.

 In this way, information is obtained about the time required for a known volume of liquid to flow under the influence of constant pressure through a capillary of known size.

 It should be noted that since the mass of air compressed in the syringe will depend on both temperature and atmospheric pressure, which are difficult to analyze in medical institutions, the inventive device is recommended mainly for obtaining information on relative viscosity. Those. under the same conditions and at the same time, the viscosity of the water and the test substrate are measured, and the ratio of the expiration times of the same volumes will display the value of the relative viscosity.

 Obviously, the needles must be used in the same size.

 When taking blood for research from a vein, the claimed device is preliminarily rinsed from the inside with a sterile solution of anticoagulants to prevent clotting or leave the required amount in the syringe cavity.

 When performing the proposed syringe viscometry, as well as during other medical procedures (blood sampling for tests, injections, probing), the use of generally accepted methods and aseptic and antiseptic agents (mask, glove, disinfectant solutions, etc.) is implied.

 The proposed device, as well as other disposable syringes and products, should be eliminated after a single use.

 The design of the device is shown in the drawings: figure 1 - at the time before measurement; FIG. 2 - at the end of the measurement; FIG. 3 - section AA, pointer-sight; FIG. 4 - section BB, open drainage hole with a bandage; FIG. 5 - section BB, closed by a drainage hole.

Figure 1 shows:
1 - the barrel of the syringe, ending pipe 2 for putting on and fixing the needle. A straight cylindrical capillary 3 is axially located in the nozzle 2 and the output part of the cylinder 3. In the cylinder wall, at the opposite end of the syringe, there is a drainage hole 4. Here, on the outside of the cylinder, there is an axial band 5 with a hole 6 in its wall 6. Rotating the band around the cylinder, you can close or open the drain hole. In this figure 1, the hole in the bandage 6 is aligned with the drainage hole 4. In the cavity of the cylinder 1 is a piston 7, continuing into the rod 8, which ends in a flat platform 9.

 A rod 10 having a longitudinal part (with respect to the axis of the syringe) located part 11 is permanently attached to the piston rod 8. At the end of the latter there is a pointer-sight 12.

 On the lateral surface of cylinder 1, a linear uniform scale (W 1 - W 5) of volumetric units of measurement is applied.

 In FIG. 1 it is indicated that the cavity of the syringe, including the capillary and the nearest part of the internal volume, is filled with the test liquid 13, the meniscus of which 14 is in contact with a portion of air inside the syringe B.

 FIG. 2 illustrates the status of the device at the end of the measurement. The drainage hole 4 is closed by a bandage 5. The piston and the pointer-sight 12 are moved towards the output of the cylinder 1. The fluid 13 flows through the capillary 3. The meniscus 14 is aligned with the pointer-sight 12.

 On AA: a section perpendicular to the axis of the syringe at the location of the pointer-sight. Here: 1 - cylinder body, 11 - the longitudinal part of the rod, 12 - pointer-sight. The latter is made in the form of a circular ring axially located around the cylinder, which is selected in order to reduce parallax errors. There is a gap between the surface of the cylinder and the target pointer.

 By BB: a similar section along the cylinder and bandage. Here: the bandage 5 is rotated around the cylinder 1 so that the drainage hole of the syringe 4 is aligned with the hole of the bandage 6. In this case, the intra-syringe space communicates with the atmosphere.

 B-B: similar section. Bandage 5 is rotated around the cylinder. The holes 4 and 6 are disconnected, the cavity of the syringe B is sealed.

 Information confirming the possibility of carrying out the invention.

 The device operates as follows.

 The first stage is preparation for measurement.

 The drainage hole 4 is closed by a bandage 5. The piston 7 of the syringe is shifted towards the outlet pipe 2 until the pointer-sight 12 coincides with the mark Ш 1 of the scale. In this case, the piston 7 does not reach the inner end of the capillary 3 and there is air in the syringe cavity.

 Then, a needle (not shown) is put on the syringe and its end is placed in the test fluid (blood, plasma, bile, semen, etc.). Pull the piston by the handle and draw liquid into the syringe to the level of Ш 2. Remove the needle from the liquid. To temporarily prevent fluid from flowing out of the syringe, it is moved to a horizontal position or the opening in the outlet pipe 2 is closed with a cap (not shown). Next, turning the bandage 5 around the cylinder, combine the bandage hole 6 and the drainage hole 4, and so on. equalize the pressure in the syringe cavity and atmosphere.

 Set the piston 7 at the mark of W 5 scale. In this case, the pointer-sight is at the mark of the scale Ш 3. Next, turning the bandage 5, open the holes 4 and 6, etc. seal the syringe cavity. As a result of this, there is air B in the cylinder cavity, the amount of which is always constant in the measurements and is determined by the position of the meniscus 14 of the fluid 13 at the level of Ш 2 and the position of the piston 7 at the level of Ш 5.

 Production measurement.

 The piston 7 is intensively shifted towards the liquid 13 until the pointer-sight 12 is aligned with the meniscus 14 at the mark of Ш 2; the piston moves up to the mark Ш 4 of the scale. Simultaneously mark the time. As a result of the shift of the piston from the mark W 5 to W 4, air B in the syringe is squeezed and begins to influence the fluid 13. The latter flows through the capillary 3 from the cylinder, and the meniscus 14 moves towards the outlet pipe 2. The operator then moves the piston 7 in this way so that the pointer-target 12 is constantly projected onto the meniscus 14, and the result will be the stability of the distance from the piston 7 to the meniscus 14. As a result, the degree of compression of air B in the syringe cavity and the excess pressure on the liquid are set.

 After reaching the meniscus 14 and the pointer-target, the mark Ш 1 of the scale marks the time and stops the measurement.

 The result of the operations performed is to obtain a time interval for which the volume of liquid (W 2 - W 1) flows out through the capillary under the influence of constant pressure. The latter, in turn, is set by reducing the air volume in the syringe by an amount determined by the movement of the piston from W 5 to W 4.

In the conducted test measurements, the relative viscosity of the investigated substrates was:
Blood: number of samples studied 13,
the range of oscillations is 3.05 - 6.13; the average value is 3.86.

Plasma: number of samples studied 13,
fluctuation limits 1.48 - 1.70; average value 1.59.

Claims (1)

 A disposable syringe containing a transparent cylindrical body with a nozzle for putting on and fixing a needle at the output end, and a piston, characterized in that a bandage is inserted axially arranged in the form of a body rim with a hole in its side wall, mounted to rotate, to align the hole with a drainage hole in the housing or overlapping openings in the housing, and a pointer sight located on a rod mated to the piston rod, while in the output of the housing there is a straight cylindrical capillary in the side the new wall of the body - a drainage hole for communication of the cavity of the piston space with the atmosphere.

Images