WO2005112762A1

WO2005112762A1 - Device and methods for monitoring and regulating anticoagulation therapy

Info

Publication number: WO2005112762A1
Application number: PCT/US2005/016821
Authority: WO
Inventors: Marc Dudas; Tsung-Chow Su
Original assignee: Florida Atlantic University
Priority date: 2004-05-14
Filing date: 2005-05-13
Publication date: 2005-12-01

Abstract

A device (100) for determining a dosage of a drug to be administered to a patient is provided. The device includes a sampling module for receiving a sample of patient blood drawn from the patient. Additionally, the device includes a viscosity determining module adjacent to the sampling module for determining a blood viscosity based upon the sample of patient blood. The device further includes a dosage determining module electrically communicating with the viscosity determining module to determine a dosage of the drug to administer to the patient based upon the blood viscosity.

Description

DEVICE AND METHODS FOR MONITORING AND REGULATING ANTICOAGULATION THERAPY

Inventors: Marc Dudas Tsung-Chow Su

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This invention claims the benefit of U.S. Provisional Application No.

60/571,161 titled Home Coumadin Monitoring Device, filed May 14, 2004.

FIELD OF THE INVENTION [0002] The present invention is related to the field of patient monitoring, and, more particularly, to devices for monitoring and regulating drug-based therapies.

BACKGROUND OF THE INVENTION [0003] Patients at risk for stroke or blood clotting can benefit considerably from a therapy comprising the regular administration of an anticoagulant such as warfarin (brand name Coumadin®) or a similar drug. Too high a dosage, though, can cause hemorrhaging in the patient, while too low a dosage can result in mobile or static blood clots that the drug is intended to prevent in the patient. Accordingly, the effectiveness of such a therapy can depend critically on monitoring certain patient parameters and, based on these, administering the prescribed anticoagulant at the proper time in a proper dosage.

[0004] Adequate monitoring of a patient being treated under an anticoagulant drug regime typically includes the weekly or bi-weekly performance of a blood test known as a prothrombin time (PT) test. The PT test typically is used to measure blood clotting time, evaluate bleeding disorders and liver damage, and generally monitor the use of an anticoagulant drug. Testing typically involves taking a ten milliliter (10 ml) blood sample drawn from the patient, and determining from the sample the viscosity of the patient's blood. Based on the tests results, a physician can prescribe a proper dosage of the anticoagulant drug for the patient.

[0005] Because of the frequency of testing normally needed, patients are often burdened with having to make frequent visits to a healthcare provider or with having to incur the costs of having the healthcare provider come to the patient. Patients, especially elderly ones, who must undergo therapy for a prolonged period can suffer the added burden of needle-induced scarring. Moreover, the need for frequent or extensive patient testing can further strain already burdened healthcare resources.

[0006] Accordingly, there is a need in the art for an effective and efficient device for monitoring patients needing an anticoagulant drug and for regulating the administration of an anticoagulant drug to such patients. More particularly, there is a need for a reduced-size, less invasive device that is neither overly expensive nor overly complicated to use. Such a device could mitigate some of the burdens on a patient who uses the device under a physician's care, and also ease the strain on scarce healthcare resources.

SUMMARY OF THE INVENTION [0007] The invention, according to one embodiment, provides a device for determining a dosage of a drug that is to be administered to a patient. The device can include a sampling module for receiving a sample of blood drawn from the patient. The device further can include a viscosity determining module in communication with the sampling module. The viscosity determining module can determine a blood viscosity based upon the sample of the patient's blood. The device also can include a dosage determining module in communication with the viscosity determining module. The viscosity determining module can determine a dosage of the drug to administer to the patient based upon the blood viscosity.

[0008] Still another embodiment is a device for monitoring a patient and regulating the administration of a drug to the patient. The device can include a handheld housing having an opening for receiving a sample of blood drawn from the patient. The device also can include a reservoir and capillary tube combination contained within the housing, the blood sample reservoir having an opening for receiving the sample of blood drawn from the patient. Additionally, the device can include a sensor contained with the housing for generating an electronic signal based upon movement of a portion of the sample of patient blood within a capillary tube. The device further can include at least one processor contained within the housing and in communication with the sensor for receiving the electronic signal, computing a blood viscosity measurement of the patient blood based upon the signal received, and determining a dosage of the drug to administer to the patient based upon the blood viscosity. [0009] A method for determining a dosage of a drug that is to be administered to a patient is yet another embodiment of the invention. The method can include obtaining a sample of blood drawn from a patient. The method also can include determining a viscosity of the patient's blood based upon the sample of blood drawn from the patient. The method further can include indicating a dosage of the drug that should be administered to the patient based upon the viscosity of the patient's blood.

BRIEF DESCRIPTION OF THE DRAWINGS [0010] There are shown in the drawings, embodiments which are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

[0011] FIG. 1 is a perspective view of a device for determining a dosage of a drug that is to be administered to a patient, according to one embodiment of the invention. [0012] FIG. 2 is a schematic diagram of a device for determining a dosage of a drug that is to be administered to a patient, according to another embodiment of the invention [0013] FIG. 3 is a schematic diagram of a device for determining a dosage of a drug that is to be administered to a patient, according to yet another embodiment of the invention. [0014] FIG. 4 is a perspective view of a device for determining a dosage of a drug that is to be administered to a patient, according to still another embodiment of the invention. [0015] FIG. 5 is a perspective view of a device for determining a dosage of a drug that is to be administered to a patient, according to another embodiment of the invention. [0016] FIG. 6 is a perspective view of a device for determining a dosage of a drug that is to be administered to a patient, according to yet another embodiment of the invention. [0017] FIG. 7 is a flowchart illustrating the exemplary steps of a method of monitoring a patient and regulating the administration of a drug to the patient, according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION [0018] The invention provides an effective and efficient way for determining a dosage of a drug that is to be administered to a patient. More particularly, the drug can be an anticoagulant such as the drug warfarin (brand name Coumadin®). The dosage of an anticoagulant that should be administered to a patient undergoing an anti-coagulating drug therapy is at least partly a function of the viscosity of the patient's blood. Unlike conventional devices, a device according to the invention does not require bulky equipment or chemical-based testing to determine the viscosity of the patient's blood. The determination can be made by the device in a less invasive, more rapid fashion. Based on this determination of the viscosity of the patient's blood, the device determines the dosage of anticoagulant that the patient should receive.

[0019] FIG. 1 provides a perspective view of a device 100, according to one embodiment of the invention. The device 100 illustratively comprises a housing 102 having a visual display 104 such as liquid crystal display in a surface portion of the housing. The visual display displays to a user of the device 100 information, which, as explained herein can comprise dosage information informing the user of the proper dosage of a drug that should be administered. In an alternative embodiment, the information is rendered as an audible output. Accordingly, the device 100 alternatively can contain a speaker for rendering an audible output in lieu of a visual display. In still another embodiment, the device 100 includes both the visual display and audio rendering capability as well. [0020] The device 100 can be a handheld device. As further illustrated, the device

100 can have a connector (not shown) to which a needle, such a disposable needle, can be selectively connected for drawing a sample of blood from a patient and conveying same to the device. In an alternative embodiment, the device 100 has an opening in the housing 102 for receiving into the housing a strip. On the strip can be a sample of blood drawn from a patient. As explained herein, a sample of blood, whether drawn into the housing 102 through a needle or provided on a strip supplied to the device 100, is used by the device 100 to determine blood viscosity and indicate a corresponding dosage of a drug for a patient. As will be apparent from the ensuing discussion, the advantageous size of the device 100 is at least in part due to the procedure implemented by the device for determining the viscosity of the blood drawn from a patient. The dimensions of the housing 102 can be, for example, three inches in length, four inches in width, and half-an-inch in thickness. Thus, according to one embodiment, the device 100 can be a handheld device.

[0021] Referring additionally to FIG. 2, the device 100 illustratively comprises a sampling module 202, a viscosity determining module 204 adjacent the sampling module, and a dosage determining module 206 that is in electrical communication with the viscosity determining module. The sampling module 202 receives a sample of blood drawn from the patient. The viscosity determining module 204 then determines the viscosity of the patient's blood based upon the sample of blood drawn from the patient. Based upon the determined blood viscosity the dosage determining module 206 in communication with the viscosity determining module determines a dosage of the drug that should be administered to the patient, the dosage being based upon the determined blood viscosity. [0022] Referring additionally now to FIG. 3, the sampling module 202 according to one embodiment comprises a blood reservoir 302 and one or more capillary tubes 304 connected with the blood reservoir. The patient's blood is received into the reservoir 302 via one of various alternative ways, including either via a needle or on a strip as discussed above. Once received into the reservoir 302, the patient's blood moves into the capillary tubes 304. The movement is the result of the capillary effect, which, as will be readily understood by one of ordinary skill in the art, arise because intermolecular forces within the liquid (i.e., blood) are weaker than the forces between the liquid and the solid (i.e., a capillary tube). A meniscus forms due to the surface tension acting upon the liquid, and subsequently, the surface tension pulls the liquid through the capillary tube. The viscosity of the fluid gives rise to the sole force opposing the surface tension. Therefore, the capillary effect is normally sufficient to move the blood through the capillary tubes 304 without external or additional forces or pressure being applied.

[0023] In one embodiment, a sample of blood drawn from the patient is supplied to the reservoir 302. For example, a sample of blood extracted from the patient with a needle is conveyed to the reservoir 302 as a result of the blood pressure of the patient and/or the capillary effect, which pulls the sample blood out of the body and into the reservoir 302. In an alternative embodiment, however, the device 100 lacks a reservoir for receiving blood drawn from the patient. Instead, a sample of blood is conveyed directly via a needle, such as a micro-needle or micro needle array for drawing a very small sample, connected to an inlet that leads into a capillary tube 304. The movement of the sample of blood through the capillary tubes 304 is driven by surface tension and opposed by viscosity as described already.

[0024] Still referring additionally to FIG. 3, the viscosity determining module 204 that determines blood viscosity illustratively comprises a sensing circuit 306 that measures the position of blood in the capillary tubes 304 as a function of time. The sensing circuit, more particularly, measures and records as multiple data points the position of the meniscus of the sample of blood. As explained below, the position and corresponding times are recorded over a designated length of the capillary tubes.

[0025] The sensing circuit 306, according to one embodiment, can comprise an optical sensor. As will be readily understood by one of ordinary skill in the art, the optical sensor can measure an intensity change in one or more light beams. Alternatively, the optical sensor can determine phase changes in the light beams by causing them to interact or interfere with one another. The former type of optical sensor can measure an intensity change using Rayleigh or Raman light scattering, or using spectral transmission changes owing to changes in attenuation of transmitted light due to absorption, for example. The latter type of optic sensor can utilize magneto-optic sensing or laser-Doppler sensing, for example. Thus, according to this embodiment, the capillary tubes 304 are transparent, thereby allowing the optical sensor to determine the movement of blood in the capillary tubes. This is done so that the optical sensor measures various aspects of light signals associated with movement of the blood sample in the capillary tubes 304, or, equivalently, by measuring chances in light intensity or phase owing to the changing position of the meniscus.

[0026] The viscosity determining module 204, according to this same embodiment, can further include a signal converter 308 or other circuitry for converting an optics-based signal into a digital or analog signal that can then be processed for calculating the rate of movement of the sample of blood within the capillary tubes 304 Accordingly, the viscosity determimng module 204 further illustratively comprises a processor 310 or other circuitry for processing the electrical signal converted from the optics-based signal. Thus, the optics- signal can indicate the positions of the meniscus formed by the sample of blood as the blood moves over time within the capillary tubes 304. Based on the electrical signals generated in response to the detected movement, a rate of flow within the capillary is thus measured. The rate of flow is used, then, to determine the viscosity of the patient's blood. [0027] More particularly, the viscosity can be determined by the processor of the viscosity determining module 204 based on the following equations. First, suction pressure due to surface tension of the blood in the capillary tubes, assuming an approximately

spherical shape, is , where σ is surface tension and R is the radius of the lumen of the R capillary tubes 304. The driving force due to the surface tension, which propels movement of the blood, is accordingly:

The wall shear stress due to blood viscosity is — — , where V = "^• is the mean flow

velocity and μ is the viscosity. Owing to the viscosity, a force opposes the forward movement of the blood within the capillary tubes 304. The resisting force is:

The calculation is facilitated using Newton's Second Law, written in the following form:

where p is blood density, which leads to the following governing equation:

where a = — ~ <—r aanndd ββ ≡≡ — . pR² R

[0028] Simultaneous measurements of the sample of blood within the capillary tubes dx d x

304 yields a data set of measurements for position, , velocity, — , and acceleration, - 7-, dt dt dx d x which from the governing equation (4), lead to a set of linear equations F dt dt² which can be solved in terms of the parameters a and β . More particularly, the parameters

a and β can be determined by linear regression of the equations = 0. From

the preceding relationship, 8μ a - - pR² ' the viscosity, μ, of the blood drawn from the patient can be evaluated once the value of a has been determined since both p and R are known.

[0029] Based on these equations, the processor 310 determines the viscosity of the patient's blood. More particularly, the signals generated by the sensing circuit 306 can be stored in a register of the processor or in another memory element (not shown) connected to the processor, thereby creating a "motion record." The motion record thus provides a collection of data corresponding to the meniscus position versus time of the flow of blood in the capillary tubes 304 based on the meniscus position versus time.

[0030] According to one embodiment, each capillary tube 304 has length in the range of approximately 1000 micrometers to approximately 2000 micrometers, and a diameter of approximately 30 micrometers to approximately 100 micrometers. Measurements of position- versus-time of the movement of blood in a capillary tube is taken over an interval of the tube, the interval being in the range of approximately 400 micrometers to 800 micrometers. Thus, for example, a sample of a patient's blood can be supplied to a capillary tube 304 having a length of approximately 1500 micrometers and a diameter of approximately 30 micrometers. The sensing circuit 306 takes position-versus-time measurements, or readings, of the sample of blood moving through the capillary tube 304 over an approximately 600-micrometer span of the capillary tube. These readings are converted into electrical signals by the signal converter 308, and processed by the processor 310 to generate recorded values of the position, x, of the meniscus, the velocity of the blood dx d x flow, —— ,, aanndd tthhee aacccceelleerraattiioonn ooff tthhee bblloooodd ffllooww,, — —_T ; , within the capillary tube 304. dt dt²

According to one embodiment, as illustrated by the preceding equations, least squares regression can be used to produce values for both a and β , and the viscosity, μ, of the blood drawn from the patient can determined based on a .

[0031] The viscosity determining module 204 further illustratively includes a memory element 312 in which is stored a data base containing prothrombin time (PT) and international normalized ratio (INR) values in the form of electronic data. As will be readily understood by one of ordinary skill in the art, the PT measures how "thin" a patient's blood is based on how many seconds the patient's blood plasma takes to clot. The LNR value is a standardized value making measurements of the PT under different conditions comparable. Thus, the PT and INR provide a patient taking an anticoagulant such as warfarin (brand name Coumadin®) a convenient measure of their drug therapy regime. For example, the patient might optimally maintain a PT of 2 to 3 LNR.

[0032] Once the viscosity of the patient's blood is determined, as already described, the viscosity can be correlated by the processor 310 with electronically representations of PT and LNR values. Thus the device is an effective and efficient mechanism for relating a measurement of the patient's blood viscosity to appropriate PT and LNR values. The values' can be relayed to the patient by the device 100 through a visual presentation with the visual display 104 and/or through an audible rendering, such as by a sequence of beeps or other audible sounds.

[0033] As will be readily understood by one of ordinary skill in the art, the processor

310 of the viscosity determining module 204 can be implemented in dedicated circuitry configured for carrying out calculations in accordance with the above-described equations. Alternatively, the processor 310 can comprise a specific-application or general-purpose computing device on which is loaded machine-readable code comprising software-based instructions for carrying out calculations in accordance with the equations. In yet another alternative embodiment, the processor can be implemented as a combination of hardwired circuitry and software-based instructions.

[0034] Still referring additionally to FIG. 3, the dosage determining module 206 illustratively includes a processor 314 and an electronic data store 316 for storing electronic data. The electronic data can comprise dosage information. Dosage information is defined as the standard dosage prescribed given certain conditions of the patient. The dosage can be correlated to the PT and LNR values applicable to the patient and can be based on conventional testing. In addition to, or in lieu of, the dosage information, the electronic data can comprise prothrombin test data. Either or both the dosage information and/or the prothrombin test data can be provided to the processor 314 for determining a proper dosage of the drug for the patient. In one embodiment, the electronic data store 316 includes a lookup table that indicates the proper dosage given the patient's blood viscosity and/or PT and LNR values. The electronic data additionally or alternatively can comprise relevant data for making a comparison between the currently prescribed dosage of anticoagulant and the recommended dosage indicated by the device. The recommendation can be stored as part of another medical library, stored as electronic data in the data store 314. Materials in the libraries can be sourced directly from available medical staff and/or resources, which provide a standard as to the correct and necessary prescribed anticoagulant dosage. [0035] The processor 314 of the dosage determining module 206 also can be implemented in one or more hardwired circuits, or in a special-purpose or programmable computing device configured to run machine-readable code for determining the desired dosage based upon the viscosity of the patient's blood. According to one embodiment, the processor of the dosage determining module 206 comprises a programmable processor in which a desired set of machine-readable instructions can be programmed. In still another embodiment of the processor 310 of the viscosity determining module 204 and the processor 313 of the dosage determining module 206 can be combined into a single processor. Likewise, in an alternative embodiment, medical libraries, patient data information, and/or other electronically stored data can be stored in a combined memory.

[0036] Referring now to FIG. 4, a perspective view of another embodiment of a device 400 for determining a dosage of a drug that should be administered to a patient is provided. As illustrated, the device 400 includes a housing 402 having a display. However, in lieu of a connector for attaching a needle, such as a disposable micro-needle, the housing 402 can contain an opening 404. A strip (not shown) on which a sample of a patient's blood has been deposited can be inserted into the housing 402 so that in the housing the strip is adjacent one or more capillary tubes 304 or a reservoir 302 connected to the capillary tubes 304. The sample of blood can be drawn, again by virtue of the capillary effect described above, from the strip so that it flows into one or more of the capillary tubes 304. [0037] FIG. 5 is a perspective view of still another embodiment of a device 500 for determining a dosage of a drug that is to be administered to a patient. The device 500 illustratively includes a housing 502 that further includes an input/output port 504 for receiving and conveying electronic data to an external computing device. Accordingly, the device 500 can be linked via the Internet, for example, to a remote database. Thus, data from one or more medical libraries that are stored electronically on a remote computing device, such as a personal computer or server, can be uploaded to a memory of the device 500. Conversely, personal data pertaining to the patient and recorded electronically in a memory of the device 500 can be downloaded to a database stored on a remote device. This provides a convenient mechanism whereby a patient can retrieve pertinent information related to a particular drug, such as an anticoagulant, as well as efficiently supply personal health data to the patient's physician or other healthcare provider.

[0038] Still another embodiment, as illustrated in FIG. 6, is a device 600 for determining a dosage of a drug that is to be administered to a patient, the device further including a wireless transceiver 606 and wireless transceiver antenna 608. Via a communications data network, the device 600 having a transceiver 606 can also permit a patient to provide data to an attending physician or other healthcare professional wirelessly when connected with a WLAN, for example. The patient can also use the device 600 to receive data via a wireless communications network. Again such data can include data from one or more medical libraries relating, for example, to the patient's particular treatment regiment. Alternatively, the data can include personal data pertaining to the patient's particular condition. The device 600 can be used if the patient wishes to supply the data via the wireless data communications network to a physician or other healthcare provider. [0039] FIG. 7 is a flowchart illustrating the exemplary steps of a method for determining a dosage of a drug that should be administered to a patient, according to yet another embodiment of the invention. The method 700 illustratively includes, at step 702, obtaining a sample of blood drawn from a patient. As illustrated, the method 700 further includes at step 704 determining a viscosity of the patient's blood based upon the sample. The method also illustratively includes, at step 706, indicating a dosage of the drug to administer to the patient based upon the viscosity of the patient's blood. The method illustratively concludes at step 708. [0040] More particularly, determining the viscosity of a patient's blood at step 704 can comprise, according to one embodiment, obtaining measures of velocity and acceleration of a sample of the patient's blood^' within one or more capillary tubes. The determining of the viscosity at step 704 can further include performing a linear regression analysis on a plurality of measurements of velocity and acceleration of the patient's blood with the one more capillary tubes.

[0041] The present invention can be realized in hardware, software, or a combination of hardware and software. The present invention can be realized in a centralized fashion in one computer system, or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system or other apparatus adapted for carrying out the methods described herein is suited. A typical combination of hardware and software can be a general purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein.

[0042] The present invention also can be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods. Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form.

[0043] This invention can be embodied in other forms without departing from the spirit or essential attributes thereof. Accordingly, reference should be made to the following claims, rather than to the foregoing specification, as indicating the scope of the invention.

Claims

CLAIMS We claim:

1. A device for determining a dosage of a drug that is to be administered to a patient, the device comprising: a sampling module for receiving a sample of blood drawn from the patient; a viscosity determining module in communication with the sampling module for determining a blood viscosity based upon the sample of blood; and a dosage determining module in communication with the viscosity determimng module for determining a dosage of the drug to administer to the patient based upon the blood viscosity.

2. The device of Claim 1, wherein the sampling module comprises at least one capillary tube, and wherein the viscosity determining module comprises a processor for determining the blood viscosity based upon movement of the sample of blood within the at least one capillary tube.

3. The device of Claim 2, wherein the processor determines the blood viscosity based upon measures of velocity and acceleration of blood within the at least one capillary tube.

4. The device of Claim 3, wherein the processor determines the blood viscosity based upon a linear regression analysis using the measures of velocity and acceleration of blood within the at least one capillary tube..

5. The device of Claim 2, wherein the at least one capillary tube comprises a transparent capillary tube, and wherein the viscosity determining module further comprises an optical sensor for sensing an optical signal that is provided to the processor for indicating movement of the sample of blood within the at least one transparent capillary tube.

6. The device of Claim 1, wherein the dosage determining module comprises an electronic data store for storing electronic data based upon at least one of dosage information and prothrombin test data, and for providing the electronic data to the dosage determining module for determining the dosage of the drug.

7. The device of Claim 6, wherein the dosage determining module further comprises a processor for processing electronic data received from the electronic data store.

8. The device of Claim 7, wherein the dosage determining module further comprises at least one of a wireless transceiver and an input/output port for receiving and conveying electronic data to an external computing device.

9. The device of Claim 1, wherein the sampling module comprises a reservoir having an opening for receiving therein the sample of blood, and a connector adjacent to the opening for connecting to a needle for drawing blood from the patient and conveying same to the reservoir.

10. A device for monitoring a patient and regulating the administration of a drug to the patient, the device comprising: a handheld housing having an opening for receiving therein a sample of blood drawn from the patient; a reservoir and capillary tube combination contained within the housing, the blood sample reservoir having an opening for receiving therein the sample of blood drawn from the patient and conveyed through the opening in the housing; a sensor contained with the housing for generating an electronic signal based upon movement of a portion of the sample of patient blood within the capillary tube; and at least one processor contained within the housing and in communication with the sensor for receiving the electronic signal, computing a blood viscosity measurement of blood based upon the signal received, and determining a dosage of the drug to administer to the patient based upon the measurement of blood viscosity.

11. The device of Claim 10, wherein the at least one processor determines the blood viscosity based upon movement of the sample of blood within the at least one capillary tube.

12. The device of Claim 11, wherein the at least one processor determines the blood viscosity based upon measures of velocity and acceleration of blood within the at least one capillary tube.

13. The system of Claim 10, further comprising an electronic data store contained within the housing and in communication with the processor for storing electronic data based upon at least one of dosage information and prothrombin test data.

14. The system of Claim 13, further comprising at least one of a wireless transceiver and an input/output port in communication with the electronic data store for receiving and conveying electronic data to an external computing device.

15. The system of Claim 10, wherein the capillary tube comprises a transparent capillary tube, and wherein the sensor comprises an optical sensor adjacent the transparent capillary tube for generating an electrical sensor in response to movement of a portion of the sample of patient blood within the transparent capillary tube.

16. The system of Claim 10, further comprising an electronic data store contained within the housing and in communication with the processor for electronically storing at least one medical library.

17. A method of determining a dosage of a drug to administer to a patient, the method comprising: obtaining a sample of patient blood drawn from the patient; determining a viscosity of the patient blood based upon the sample of patient blood; and indicating a dosage of the drug to administer to the patient based upon the viscosity of the patient blood.

18. The method of Claim 17, wherein indicating a dosage further comprises determining a dosage to administer to the patient based upon at least one of patient history data, prothrombin test data, and data culled from at least one medical library.

19. The method of Claim 17, wherein determining viscosity comprises obtaining measures of velocity and acceleration of patient blood within the at least one capillary tube.

20. The method of Claim 19, wherein determining viscosity comprises performing a linear regression analysis based upon the obtained measures of velocity and acceleration.