Catheter Insertion Device with Blood Analyzer
20210212617 · 2021-07-15
Inventors
Cpc classification
A61B5/1535
HUMAN NECESSITIES
A61B5/157
HUMAN NECESSITIES
A61B5/150992
HUMAN NECESSITIES
International classification
A61B5/157
HUMAN NECESSITIES
A61B5/153
HUMAN NECESSITIES
Abstract
A device and method yielding a blood analysis employable in combination with an introducer for a catheter for a concurrent testing of blood from the introducer flash chamber during placement of a venous catheter. The device employs a colorimetric blood analysis to provide the user a visually discernable alert to the results of tested blood concurrent with the placement of the catheter with the introducer.
Claims
1. An apparatus for testing blood of a patient, the apparatus comprising: a catheter or needle for being inserted into a vein or artery of a patient to convey a sample of blood from the patient; a chamber in fluid communication with the catheter or needle, the chamber being formed by one or more sidewalls, the chamber being configured to receive a first portion of the sample of blood conveyed from the patient via the catheter or needle; and a substrate arranged along at least one of the one or more sidewalls of the chamber, the substrate configured to generate, upon contact with the first portion of the sample of blood in the chamber, a visually discernable reaction to a presence, a non-presence or a threshold level of a substance, chemical or content in the first portion of the sample of blood, the visually discernable reaction being viewable through the at least one of the one or more sidewalls of the chamber.
2. The apparatus in accordance with claim 1, further comprising a housing that defines the one or more sidewalls that form the chamber.
3. The apparatus in accordance with claim 1, wherein the one or more sidewalls of the chamber define a fluid pathway from the catheter or needle to the substrate.
4. The apparatus in accordance with claim 1, wherein the visually discernable reaction is a dual threshold indication, in which a first visually discernable reaction is generated upon detection of a first threshold level of the substance, chemical or content in the first portion of the sample of blood, and in which a second visually discernable reaction is generated upon detection of a second threshold level of the substance, chemical or content in the first portion of the sample of blood.
5. The apparatus in accordance with claim 3, further comprising a separation membrane within the fluid pathway proximate to the substrate, the separation membrane being configured to allow only blood plasma from the first portion of blood to contact the substrate.
6. The apparatus in accordance with claim 1, further comprising a microporous membrane positioned in the chamber proximate the substrate, the microporous membrane being configured to retain at least some of the first portion of blood for a period of time.
7. The apparatus in accordance with claim 1, wherein the catheter or needle is further configured to convey subsequent portions of the sample of blood so as to bypass the chamber.
8. An apparatus for testing blood of a patient, the apparatus comprising: a catheter or needle for being inserted into a vein or artery of a patient to convey a sample of blood from the patient; a housing having an input in fluid communication with the catheter or needle, and an output, the housing defining a chamber being formed by one or more sidewalls, the chamber being configured to receive a first portion of the sample of blood conveyed from the patient via the catheter or needle; and a substrate arranged along at least one of the one or more sidewalls of the chamber defined by the housing, the substrate configured to generate, upon contact with the first portion of the sample of blood in the chamber, a visually discernable reaction to a presence, a non-presence or a threshold level of a substance, chemical or content in the first portion of the sample of blood, the visually discernable reaction being viewable through the at least one of the one or more sidewalls of the chamber.
9. The apparatus in accordance with claim 8, wherein the flash chamber is further configured to at least temporarily hold the first portion of blood of the sample of blood.
10. The apparatus in accordance with claim 8, wherein the one or more sidewalls of the chamber define a fluid pathway from the catheter or needle to the substrate.
11. The apparatus in accordance with claim 8, wherein the visually discernable reaction is a dual threshold indication, in which a first visually discernable reaction is generated upon detection of a first threshold level of the substance, chemical or content in the first portion of the sample of blood, and in which a second visually discernable reaction is generated upon detection of a second threshold level of the substance, chemical or content in the first portion of the sample of blood.
12. The apparatus in accordance with claim 8, further comprising a separation membrane proximate the substrate, the separation membrane being configured to allow only blood plasma from the first portion of blood to contact the substrate.
13. The apparatus in accordance with claim 8, further comprising a microporous membrane positioned in the chamber proximate the substrate, the microporous membrane being configured to retain at least some of the first portion of blood for a period of time.
14. The apparatus in accordance with claim 8, wherein the catheter or needle is further configured to convey subsequent portions of the sample of blood so as to bypass the chamber.
15. The apparatus in accordance with claim 13, wherein the microporous membrane includes a clotting factor to clot at least some of the first portion of blood.
Description
BRIEF DESCRIPTION OF DRAWING FIGURES
[0040] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate some, but not the only nor exclusive examples of embodiments and/or features of the disclosed device. It is intended that the embodiments and figures disclosed herein are to be considered illustrative of the invention herein, rather than limiting in any fashion.
[0041] In the drawings:
[0042]
[0043]
[0044]
[0045]
[0046]
[0047]
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[0051]
DETAILED DESCRIPTION OF THE INVENTION
[0052] Now referring to drawings in
[0053] The various modes of the testing component 12 primarily depict a substrate of planar material adapted to the task. However, the substrate is capable of numerous other modes, and any testing component 12 or other component which may be placed in operative fluid communication with a flash chamber 14 of an introducer 16, and which will react in a visually discernable manner to a communication of blood or plasma thereto when a particular substance, chemical, or other element carried in the blood, is considered within the scope of this application.
[0054] A colorimetric reagent pad 32 is preferable to determine the concentration of glucose in blood plasma and provide a visually discernable means for the user to view results or an alert. A threshold indication system may be used such that when the concentration is below a predetermined level, the reagent pad 32 remains colorless, and when the concentration goes above that point, a colored dye is activated in the reagent pad 32, and can be detected easily by the human eye.
[0055] In a preferred variation, a dual threshold indication system is used such that the reagent pad 32 remains colorless below a predetermined level, changes one color when above the first threshold, and turns a second color when above the second threshold. An example of the dual indication system would be such that the reagent pad 32 is colorless below a glucose concentration of 80 mg/dl indicating low blood sugar, green when between 80 mg/dl and 300 mg/dl indicating normal blood sugar, and dark blue when above 300 mg/dl indicating high blood sugar.
[0056] The threshold indication system is accomplished through precise control of the volume of plasma that is able to contact and react on the substrate such as the reagent pad 32, and using precise amounts of scavenger molecules that are consumed before the reaction with the dye is visible. This can either be accomplished by consuming an intermediate reactive species or quickly reacting to turn the dye back to a colorless state once it has reacted with the intermediate reactive species. Once all the scavenger molecules have reacted, reactions can proceed with the dye or the dye is no longer reversed to a colorless state.
[0057] In the dual threshold variation, reaction speeds are controlled through enzyme concentrations and the concentration of other reactive species such that the scavenger molecules are reacted before the other two dyes are able to react at an eye-detectable level. The first dye, which is also present in a precisely controlled amount like the scavenger molecules, then reacts before the second dye is able to react at an eye-detectable level. But once all the first dye has reacted, the reaction proceeds onto the second dye.
[0058] The reagent pad 32 form of the test substrate, may be created by conventional means in the art such as by dipping a hydrophilic membrane such as filter paper into a solution containing all the starting chemicals and enzymes. Through control of the concentration of chemicals in this solution, and conventional knowledge about how much solution is adsorbed onto the reagent pad 32 during dipping, the amount of starting chemicals can be controlled.
[0059] For example, and in no way limiting as to the substance which can be visually discerned using the device 10 and method herein, glucose is first reacted with an enzyme to give rise to a more reactive species that is able to react appropriately with either the scavenger molecules or dyes. In one embodiment, glucose reacts with the enzyme glucose oxidase and oxygen to create gluconic acid and hydrogen peroxide.
[0060] Hydrogen peroxide then proceeds to react with a colorless phenolic in the presence of 4-aminoanipyrene (AAP) and the enzyme horseradish peroxidase to create a colored dye and water. This is explained further in U.S. Pat. No. 6,599,474 B2.
[0061] There is a wide range of phenolic compounds that can be used, and one that gives a light green color when reacted with AAP is 3-hydroxyquinaldine [2].
[0062] To create a threshold visually discernable indication, a reducing agent can be used to convert the colored dye back into a colorless form as shown in reaction. Some possible reducing agents that could participate in reaction include ferrous sulphate and magnesium chloride.
[0063] A scavenger compound can also be used to create a threshold indication by consuming the majority of the hydrogen peroxide before it can participate in reaction (2) and indicate the dye. One such compound, 1-cysteine can react directly with hydrogen peroxide.
[0064] If may be desirable to control the reaction enzymatically, and ascorbate can be used in conjunction with glutathione to do so for example. An advantage to using enzymatically controlled reactions is that enzyme concentrations can be used to obtain better control over reaction rates.
[0065] Note, that because ascorbate is regenerated in such a reaction, the stoichiometrically controlled species for creating a threshold indication is glutathione.
[0066] For the secondary threshold indication, hydrogen peroxide reacts with iodine ions and hydrogen ions to create triiodide and water. The triiodide can then form a deep blue complex with starch. Some control over the reaction rate can be achieved by controlling the pH and concentration of iodine ions.
[0067] An alternate to using hydrogen peroxide as the reactive species is NADH. This is described in U.S. Pat. No. 5,200,325. Glucose reacts with NAD+ and the enzyme glucose dehydrogenase to create NADH and gluconolactone. The NADH is the reactive species that continues on to the next reactions.
[0068] Pyruvate can be used as a scavenger to stop any activation of a dye below a specified threshold of glucose. The conversion of the lactate into acetate ensures that the lactate does not undergo a reverse reaction or involve itself in any side reactions.
[0069] Once all the pyruvate is consumed, the NADH can proceed to react with an indicator in the pad. In the presence of lipoamide dehydrogenase, NADH can react with lipoamide (LA) to create a reduced form of lipoamide.
[0070] The reduced form of lipoamide can react with various disulfide indicators to create color. For example, 2,2′-dithio-bis(pyridine-N-oxide) (DTPO) may be employed. The reduced form of the disulfide indicator produces color. The amount of LA and DTPO can be precisely controlled along with the amount of lipoamide dehydrogenase enzyme to have all the DTPO and LA be in a reduced state at a desired threshold concentration of glucose. Once all the DTPO and LA are in a reduced state, a second threshold reaction can become the primary indication. In this case the NADH can proceed to react with 2-(p-iodophenyDJ-(p-nitrophenyl)-5-phenyltetrazolium chloride (INT) in the presence of the enzyme diaphorase to create NAD+ and formazan, the colored indicator and reduced form of INT.
[0071] This is an example of a dual threshold color indication using NADH as the reactive species. The colors of the specific indicators used in this example may not be optimized for this application, but it is expected that there are multiple colors that can be produced with similar molecules to the ones used. The reagent pad 32 or testing substrate, can be formed to be ethanol sensitive by changing glucose oxidase to alcohol oxidase in the first reaction noted above which generates hydrogen peroxide. Similarly, glucose dehydrogenase can be replaced with alcohol dehydrogenase which generates NADH in reaction. The rest of the chemistry should proceed similar to above.
[0072] The aforementioned are simply examples of modes of enabling the device 10 with a reagent pad 32 which after a duration of time of exposure to communicated blood plasma, will visually react to the presence of a substance or analytes thereof in the blood plasma, or to analytes of a substance or the substance itself above a threshold level. The employed testing substrate such as depicted reagent pad 32 can be segmented to multiple zones to include multiple reactions to the communicated plasma, to provide multiple individual visually discernable alerts for respective multiple individual substances present, and/or above or below threshold levels by volume.
[0073] As depicted in
[0074] In all modes of the device 10 where the needle 18 is coaxial to the catheter 20, the point of the needle 18 is seen to extend from the distal tip of the catheter 20, which is mounted on the luer lock 22 component. This allows the needle 18 to be inserted through the flesh of the patient and be positioned within the desired vein or artery.
[0075] Upon a proper communication of the distal end of the needle 18 with the interior of a vein or artery, blood immediately flows through the axial conduit of the needle 18 and into the flash chamber 14 thereby signifying proper positioning. The flash chamber 26 on conventional introducers 16 can contain one or more one-way air valves, or membranes, to vent or allow air to escape as blood enters. Conventionally one such air passage is provided by a flash plug 26.
[0076] As shown in
[0077] In another preferred mode of the device 10 per
[0078] In operation herein, in all modes where a testing component 12 is employed, blood from the flash chamber 14 is communicated to the testing component 12. During such communication to the testing substrate, plasma is separated from the whole blood using a plasma separation membrane 30 (
[0079] Red blood cells have an approximate diameter of 6.2-8.2 μm and by using an asymmetric membrane 30 where the pore size varies in a gradient starting on the receiving side from values such as 50 μm to 0.1 μm, red blood cells will be trapped in the receiving side of membrane. The membrane itself is made of a hydrophilic material that will readily soak up and wick plasma, so the red blood cells are trapped on the receiving side of the membrane while the plasma is wicked to the opposite end. This ensures that only plasma will soak into the reagent pad.
[0080] In one preferred mode of the device 10, it is desired to induce a blood clot between the blood in the flash chamber 14 and that which is communicated through the plasma separation membrane 30 to the test substrate as a means for limiting the volume of fluid communicated through the membrane 30, and then to the reagent pad 32, to stop an excess communication and a continuous diffusion of glucose for example which can cause a testing error.
[0081] Means to induce clotting on or in the membrane 30 such as by causing blood clots, may be induced by several different compounds. Potassium ferrate is one used in U.S. Pat. No. 6,187,347 B1, and kaolin and zeolite are used in US patent application US20090299253 A1. Blood has a natural clotting cascade to seal up wounds to the body, and it may be desired to induce and accelerate clotting to seal up the plasma separation membrane 30 in instances where the testing being done requires a certain volume of fluid communicated to the substrate having the visually discernable test results thereon to be accurate.
[0082] The clotting speed, and therefor the volume of plasma or fluid passed through the membrane 30, may be tightly controlled by varying the amount of the clotting agent on, adjacent to, or within the separation membrane 30, to allow plasma flow before clotting only for a sufficient time for a determined volume of blood plasma to communicate through the plasma separation membrane 30, and thereby stop glucose diffusion in the testing component, beyond that point in time where the volume of plasma passes through.
[0083] An alternative, described in patent application WO2010062734 is using chitosan, which does not induce the full clotting cascade, but only forms a localized clot. It may be desirable to pattern the chitosan in such a way on the plasma separation membrane 30, such that there is not 100% coverage initially, but after contact with the blood and subsequent wicking through the plasma separation membrane, all contact of blood to the plasma separation membrane 30 has ceased after the desired amount has been absorbed. In a preferred embodiment, a chitosan gel or solution is cast or sprayed directly on the plasma separation membrane and dried, forming a layer. The chitosan matrix molecular weight and thickness is tightly controlled to allow a precise amount of plasma through the plasma separation membrane before being sealed.
[0084] Thereafter, the plasma wicks from the plasma separation membrane 30 and fluidly communicates with the substrate providing the visually discernable outcome to the test component 12 such as the reagent pad 32. The reagent pad 32 may be configured in any manner of conventional ways to produce a visually discernable alert, such as a color or color change, when a threshold level of a substance analyte or the substance itself being tested-for, is discerned. The reagent pad 32 may remain the original color if the agent or material being tested for is not present in the plasma, or if it is present below a specified concentration. If the concentration is above the specified level, the reagent pad 32 will have a colored change indication detectable by the human eye.
[0085] Shown in
[0086] This engageable configuration would allow the employment of a kit of testing components 12 such as in
[0087] In
[0088] As shown in
[0089] Blood is communicated to the blood to a plasma separation membrane 30 which filters the red cells and passes blood plasma to the test substrate shown in this mode as reagent pad 32. Also shown in
[0090] Plasma communicating to and through the reagent pad 32 will communicate through a moisture indicator layer 33 and thereafter cease further communication rearward once it encounters the backing layer 35 which is configured to pass air from the flash chamber 14 to the atmosphere but block the larger fluid molecules from exit. The backing layer 35 thus provides means for venting air from the flash chamber 14 to allow blood and plasma to fill it.
[0091] The reagent pad 32 or substrate, as noted herein, in all modes of the device 10 such as of
[0092] As shown in
[0093] A transparent wall or cover 43 is placed in sealed engagement with a base 45, (which may be the wall forming the flash chamber 14) and one or a plurality of apertures 47 will communicate with passages 41 providing fluid communication with the flash chamber 14. This mode can be formed integral to the housing 17, or engaged on the exterior thereto using adhesive or other means to engage the base 45 or the cover 43 to a wall of the housing 17. Or, as noted, if manufactured, it may be formed integral to the wall defining the flash chamber 14 or introducer 16.
[0094] In all modes of the device 10 the testing component 12 can include substrate adapted with appropriate test material to produce a threshold visually discernable alert, which may have one, or a plurality of concurrent different visually discernable results possible. As shown in
[0095] As shown in
[0096] Particularly preferred in any mode of the device 10 when used in an operative engagement with an introducer 16 would be a colorimetric blood glucose or ethanol test, using a substrate such as the reagent pad 32 configured to provide a visually discernable alert, when blood glucose or ethanol concentration is beyond a predetermined point whereby the reagent pad 32 reacts in a manner to provide a visually discernable alert or result.
[0097] However, any substance or level thereof in the blood may be tested and a visually discernable alert produced using the appropriate reagents which react to the presence of a substance or marker for such in the blood. This provides the medical provider with valuable information concurrent with the introduction of the catheter to the patient with no extra effort or time.
[0098] Any of the catheter components as described above can be produced from any of the standard disposable and non-toxic plastics or metals used with other intravenous catheters. The color indicator providing a visually discernable alert to the user for the substance or level of substance in the blood communicated to a flash chamber 14 may be any material which will react to such substances in the blood and provide the visual alert which as known to those skilled in the art may be any of thousands of potential tests and resulting visually discernable reactions.
[0099] In a method of use of the device 10 herein, a user will employ an introducer 16 to place a catheter in the vein of a patient. In a first step, if the introducer 16 is pre-configured with a testing component 12 in communication with the flash chamber 14 of the introducer 16, the user will pierce the vein of the patient and discern if blood is communicated to the flash chamber 14. Subsequent to such communication to the chamber 14, the user will view the reagent pad 32 within the testing component 12 to ascertain if a visually discernable alarm or result has been found.
[0100] If employing an introducer 16 without a pre-mounted testing component 12, the user will choose a testing component 12 from a group which will provide a desired visual alarm to the presence of a substance or level thereof once blood from the flash chamber 14 reaches it. The user will engage the testing component 12 into an aperture of the introducer 16 which is configured to communicate plasma to the testing component 12. Thereafter the user will engage the needle of the introducer 16 with the vein of a patient, whereby blood will communicate to the flash chamber 14, and cause the substrate or reagent pad 32 of the chosen testing component 12 engaged, to react and either provide a visually discernable alarm or result to the user if the substance being tested for is present or is present at a level above a threshold.
[0101] As noted, any of the different configurations and components can be employed with any other configuration or component shown and described herein. Additionally, while the present invention has been described herein with reference to particular embodiments thereof and steps in the method of production, a latitude of modifications, various changes and substitutions are intended in the foregoing disclosures, it will be appreciated that in some instance some features, or configurations, or steps in formation of the invention could be employed without a corresponding use of other features without departing from the scope of the invention as set forth in the following claims. All such changes, alternations and modifications as would occur to those skilled in the art are considered to be within the scope of this invention as broadly defined in the appended claims.
[0102] Further, the purpose of any abstract of this specification is to enable the U.S. Patent and Trademark Office, the public generally, and especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. Any such abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting, as to the scope of the invention in any way.