Process and device for determining parameters of interest in living organisms

• US 5,237,993 A
• Filed: 11/19/1991
• Issued: 08/24/1993
• Est. Priority Date: 02/02/1987
• Status: Expired due to Term

• Current Assignee: Falco Skrabal
• Original Assignee: Avl Medical Instruments AG (Roche Holding AG)
• Inventors: Skrabal, Falko
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): Rafa, Michael
• Application Number:
  US07/794,244
• Time in Patent Office: 644 Days
• Field of Search: 128/632-635, 128/637, 128/DIG. 13, 604/27, 604/28, 604/48-50
• US Class Current: 600/309
• CPC Class Codes: A61B 10/0045 Devices for taking samples of body liquids devices for taking blood samples A61B5/15
• CPC Class Codes: A61B 10/007 for taking urine samples measuring urological functions A61B5/20; genital receptacles A61F5/451; urinals for bed-ridden persons A61G9/006
• CPC Class Codes: A61B 5/14525 using microdialysis
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/15003 for venous or arterial blood
• CPC Class Codes: A61B 5/150244 Rods for actuating or driving the piston, i.e. the cylindrical body that sits inside the syringe barrel, typically with an air tight seal, and slides in the barrel to create a vacuum or to expel blood
• CPC Class Codes: A61B 5/150251 Collection chamber divided into at least two compartments, e.g. for division of samples injection syringes having more than one chamber A61M5/19; syringes for injection of two or more media A61M5/2448, A61M5/284; sample preparation for further analysis A61B5/150755
• CPC Class Codes: A61B 5/150396 Specific tip design, e.g. for improved penetration characteristics
• CPC Class Codes: A61B 5/150511 Details of construction of shaft
• CPC Class Codes: A61B 5/153 Devices specially adapted for taking samples of venous or arterial blood, e.g. with syringes
• CPC Class Codes: A61B 5/155 Devices specially adapted for continuous or multiple sampling, e.g. at predetermined intervals devices loaded with multiple lancets simultaneously A61B5/15146
• CPC Class Codes: A61B 5/157 Devices characterised by integrated means for measuring characteristics of blood
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61M 1/77 Suction-irrigation systems aspiration tips supplying fluids A61M1/85; specific for negative pressure wound therapy A61M1/92; combined with tracheal tubes A61M16/0463
• CPC Class Codes: A61M 1/85 with gas or fluid supply means, e.g. for supplying rinsing fluids or anticoagulants for negative pressure wound therapy A61M1/92, A61M1/94; combined with tracheal tubes A61M16/0463; dental instruments with combined rinsing and aspirating A61C17/0208
• CPC Class Codes: A61M 2230/201 Glucose concentration
• CPC Class Codes: A61M 2230/65 Impedance, e.g. conductivity, capacity
• CPC Class Codes: A61M 5/1723 : using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: Y10S 128/13 : Infusion monitoring

Abstract

In order to determine at least one parameter of interest in a living organism, a perfusion is directly introduced in the tissues. After its partial balancing by the tissue parameter of interest, the perfusion fluid is collected and analyzed for the parameter of interest, as well as for endogenous or exogenous marker properties indicative of the degree of interaction between the perfusion fluid and the tissue, in such a way that the parameters of interest can be determined with the help of such characteristic properties. Contrary to usual processes, used exclusively inside blood vessels or other body cavities filled with liquid, this process creates in the tissues, i.e. in the closed cellular structure, a previously inexistent cavity, in which the perfusion fluid introduced in the tissue interacts directly with the organic tissue, with no intervening membranes. The transfer of the measurement site into the tissue completely eliminates the risk of the thromboses and embolies, besides strongly reducing the risk of infection.

Claims

1. A device for determining the concentration of at least one substance of interest in tissue of a living organism, comprising:

(a) a subcutaneous needle/catheter insertable into the tissue of a living organism, said subcutaneous needle/catheter defining a tip and first and second passages, said first passage being configured as an exchange channel with first openings in wall areas for communication with said tissue and the second passage being configured as a drainage passage, said exchange channel being in communication with said drainage passage via at least one second opening near said tip of said subcutaneous needle/catheter;

(b) a feeding/draining unit for feeding perfusion fluid into said exchange channel and draining said perfusion fluid from said drainage passage after said perfusion fluid has contacted said tissue via said first openings and become partially balanced by said at least one substance of interest in said tissue,

(c) an analyzing unit connected to said drainage passage for analyzing said perfusion fluid for said at least one substance of interest, and including means for analyzing endogenous or exogenous marker properties indicative of the degree of interaction between said perfusion fluid and said tissue, and

(d) an evaluation unit connected to said analyzing unit and including means for determining the concentration of said at least one substance of interest using said degree of interaction.

2. A device according to claim 1, wherein said feeding/drainage unit comprises a reservoir for said perfusion fluid, means forming a feeder passage which connects said reservoir with said exchange channel, a pump for circulation of perfusion fluid from said reservoir into said feeder passage, and a collecting vessel for perfusion fluid;

wherein said analyzing unit includes sensors; and

wherein said device includes a calibrating unit for calibrating said sensors in said analyzing unit, said calibrating unit comprising a container for calibrating solution, a valved connecting passage which connects said container with said analyzing unit, a pump for circulating said calibrating solution into said connecting passage, and a collecting vessel for said calibration solution.

3. A device according to claim 2, wherein said subcutaneous needle/catheter defines a base formed as a plug-in connection and wherein said feeder passage is contained in a plug which is insertable into said plug-in connection to provide communication between said feeder passage and said exchange channel.

4. A device according to claim 1, including a drug delivery unit which comprises a drug container, a drug feeding tube connecting said drug container with said subcutaneous needle/catheter and defining a drug discharge opening for discharging drug into said tissue, and a drug delivery pump for circulating drug from said drug container into said drug feeding tube.

5. A device according to claim 1, wherein said subcutaneous needle/catheter consists of first and second cannulas of respectively larger and smaller diameters, said second cannula being within said first cannula, said exchange channel being formed in an annular area between said first and second cannulas, said inner cannula not extending to said tip of said subcutaneous needle/catheter.

6. A device according to claim 1, wherein said subcutaneous needle/catheter includes a partition which extends along a length of said subcutaneous needle/catheter to provide said exchange channel and said drainage passage.

7. A device according to claim 1, wherein said subcutaneous needle/catheter defines a drug release opening near said top thereof and a third passage configured as a drug feeder tube which communicates with said drug release opening.

8. A device according to claim 1, wherein said subcutaneous needle/catheter consists of an outer cannula and an inner cannula, said exchange channel being formed between said inner cannula and said outer cannula, wherein said inner cannula includes a partition which defines said drainage passage and said drug feeding tube, wherein said first openings are in said outer cannula and said at least one second opening is in said inner cannula so as to communicate said exchange channel and said drainage passage.

9. A device according to claim 2, wherein a negative pressure sensor if provided in one of said drainage passage upstream of said analyzing unit, said drainage passage between said analyzing unit and said collecting vessel for perfusion fluid and said collecting vessel for said perfusion fluid, and wherein a temperature sensor is provided in said analyzing unit.

10. A device according to claim 1, including one of an ionic sensor and a conductivity meter in said analyzing unit for determining said marker variable and which acts as a negative pressure sensor, registering adequate filling of a measuring capillary in said analyzing unit, a signal of said evaluation unit effecting switchover or switch-off of a suction pump for said perfusion fluid, and wherein said device includes one of an acoustical alarm and an optical display means.

11. A device according to claim 1, wherein said analyzing unit for measuring said at least one substance to be analyzed and said endogenous or exogenous marker variables is configured as a replaceable unit, and including shutting means to close said passages connected to said analyzing unit upon disconnection of said replaceable unit from said subcutaneous needle/catheter.