Process for determining parameters of interest in living organisms

• US 5,097,834 A
• Filed: 08/02/1989
• Issued: 03/24/1992
• Est. Priority Date: 02/02/1987
• Status: Expired due to Term

• Current Assignee: Falco Skrabal
• Original Assignee: AVL AG
• Inventors: Skrabal, Falko
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): SHUMAKER, STEVEN
• Application Number:
  US07/415,267
• Time in Patent Office: 965 Days
• Field of Search: 128/632, 128/635, 128/637, 128/DIG. 13, 128/898, 436/67, 436/68, 604/27, 604/28, 604/48-50
• US Class Current: 600/366
• 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 fluid 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 parameter 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 method for determining the actual concentration of at least one substance to be analyzed in a living organism, comprising the steps of:

introducing a perfusion fluid directly into the tissue of said living organism;

collecting said perfusion fluid after partial equilibration with said substance to be analyzed;

testing said perfusion fluid for said substance to be analyzed to obtain a provisional concentration value of said substance;

additionally testing said perfusion fluid for at least one endogenous marker variable with a known tissue value to obtain a test value;

calculating the degree of partial equilibration from said tissue value and said test value; and

calculating the actual concentration of said substance to be analyzed from said degree of partial equilibration and said provisional concentration value.

2. A method according to claim 1 wherein at least one parameter from the group of ionic concentration, conductivity, impedance, osmolarity and density is analyzed as said endogenous marker variable of said perfusion fluid.

3. A method according to claim 1, wherein an analyzing unit for analyzing said substance to be analyzed and said marker variables is calibrated at specific intervals of time by means of a calibrating medium.

4. A method according to claim 1, wherein a drug is applied automatically, in accordance with the concentration of said substance to be analyzed.

5. A method according to claim 1, wherein said substance to be analyzed is glucose, the concentration of said substance to be analyzed being determined along with the endogenous sodium or chloride concentration as said marker variable of said perfusion fluid.

6. A method according to claim 1, wherein said substance to be analyzed is glucose, the concentration of said substance to be analyzed being determined along with the conductivity as said marker variable of said perfusion fluid.

7. A method according to claim 1, wherein a low-glucose, low-ion solution of approximately isotonic character is used as said perfusion fluid.

8. A method according to claim 1, wherein a substrate preventing a reaction of said substance to be analyzed is added to said perfusion fluid.

9. A method according to claim 8, wherein said substance to be analyzed is glucose and wherein said substrate is 3-phosphoglycerate, which is added to said perfusion fluid.

10. A method according to claim 1, wherein the diffusion constants of one or more of said marker variables and of said substance to be analyzed are entered for calculating the concentration of said substance to be analyzed.

11. A method according to claim 1, wherein a gaseous substance is used for separation of said perfusion fluid and a calibrating medium.

12. A method according to claim 1, wherein said substance to be analyzed and said marker variable are measured by at least two independent analyzing units, and wherein alarm signals are given if said measured values do not match.

13. A method for determining the actual concentration of at least one substance to be analyzed in a living organism, comprising the steps of:

introducing a perfusion fluid directly into the tissue of said living organism, said perfusion fluid comprising an exogenous marker substance with known actual concentration;

collecting said perfusion fluid after partial equilibration with said substance to be analyzed;

testing said perfusion fluid for said substance to be analyzed to obtain a provisional concentration value of said substance;

additionally testing said perfusion fluid for said exogenous marker substance to obtain a test value;

calculating the degree of partial equilibration from said actual concentration value and said test value; and

calculating the actual concentration of said substance to be analyzed from said degree of partial equilibration and said provisional concentration value.

14. A method according to claim 13, wherein at least one additional substance to be detected by chemical or physical methods is added to said perfusion fluid for measurement of said exogenous marker substance.

15. A method according to claim 13, wherein said substance to be analyzed is glucose, the concentration of said substance to be analyzed being determined along with the concentration of a dye added to said perfusion fluid as said marker substance.