SYSTEMS AND METHODS TO REDUCE FLUID CONTAMINATION

• US 20110313318A1
• Filed: 06/16/2011
• Published: 12/22/2011
• Est. Priority Date: 06/17/2010
• Status: Active Grant

• Current Assignee: OptiScan Biomedical Corporation
• Original Assignee: OptiScan Biomedical Corporation
• Inventors: Rule, Peter, Braig, James R., Keenan, Richard, Callicoat, David N.
• Granted Patent: US 9,848,821 B2
• Time in Patent Office: Days
• US Class Current: 600/581
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/15003 for venous or arterial blood
• CPC Class Codes: A61B 5/150221 Valves
• CPC Class Codes: A61B 5/150229 Pumps for assisting the blood sampling
• CPC Class Codes: A61B 5/150236 Pistons, i.e. cylindrical bodies that sit inside the syringe barrel, typically with an air tight seal, and slide in the barrel to create a vacuum or to expel 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 5/150389 Hollow piercing elements, e.g. canulas, needles, for piercing the skin
• CPC Class Codes: A61B 5/150503 Single-ended needles hollow piercing element tip design A61B5/150396, needle sets for catheters A61M25/06, needles for bringing media into the body A61M5/32
• CPC Class Codes: A61B 5/150755 Blood sample preparation for further analysis, e.g. by separating blood components or by mixing
• CPC Class Codes: A61B 5/150992 Blood sampling from a fluid line external to a patient, such as a catheter line, combined with an infusion line; blood sampling from indwelling needle sets, e.g. sealable ports, luer couplings, valves tubing connectors and couplings A61M39/00
• 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 5/157 Devices characterised by integrated means for measuring characteristics of blood
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/6866 Extracorporeal blood circuits, e.g. dialysis circuits
• CPC Class Codes: A61M 2005/14208 with a programmable infusion control system, characterised by the infusion program
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2230/201 : Glucose concentration
• CPC Class Codes: A61M 5/1415 : Stands, brackets or the like for supporting infusion accessories
• CPC Class Codes: A61M 5/1452 : pressurised by means of pistons
• CPC Class Codes: A61M 5/1723 : using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

Abstract

Methods and systems for determining the concentration of one or more analytes from a sample such as blood or plasma are described. The systems described herein can be configured to withdraw a certain volume of sample from a source of bodily fluid, direct a first portion of the withdrawn sample to an analyte monitoring system and return a second portion of the sample to the patient. The analyte monitoring system can include an automated blood withdrawal system that is configured to withdraw blood from the patient'"'"'s vasculature at low pressure and/or withdrawal rates so as to reduce or prevent contamination of the withdrawn fluid from the infusion fluids.

Claims

1. A system for reducing contamination risk in drawing fluid from vasculature, the system comprising:

a tube configured to connect to a multi-lumen catheter, the multi-lumen catheter having;

a proximal port comprising an independent lumen that provides a fluid path between an extracorporeal opening and an intravascular opening that is positioned upstream when the multi-lumen catheter is inside a vessel having a fluid flow;

a distal port comprising an independent lumen that provides a fluid path between the extracorporeal opening and the intravascular opening that is positioned downstream from the proximal port when the multi-lumen catheter is inside a vessel having a fluid flow; and

a medial port comprising an independent lumen that provides a fluid path between the extracorporeal opening and the intravascular opening that is positioned between the proximal port and the distal port;

the distal and medial ports each configured to allow infusion of an infusate into the vessel from their intravascular openings downstream from the intravascular opening of the proximal port;

the tube configured to connect to the proximal port of the multi-lumen catheter without leaking, the tube having an inner lumen that is smaller than the inner lumen of the independent lumen of the proximal port; and

a fluid pressure system in fluid communication with the inner lumen of the tube and configured to create a pressure in the inner lumen that is automatically controlled to be less than 10 psi and/or provide a flow rate of between approximately 1 and 10 ml per minute such that the amount of contaminating infusate that is drawn into the intravascular opening of the proximal port is limited to less than 10 parts per million.

2. The system of claim 1, wherein the fluid pressure system is configured to create a negative pressure in the inner lumen that is between approximately 40% and approximately 99% of the pressure in the vessel.

3. The system of claim 1, wherein the fluid pressure system comprises a syringe pump.

4. The system of claim 1, wherein a diameter of the inner lumen of the tube is between approximately 0.01 inches and approximately 0.04 inches.

6. The method of claim 1, wherein the automated system can control the fluid pressure system to create a negative pressure in the inner lumen that is between approximately 40% and approximately 99% of the pressure in the vessel.

7. The method of claim 1, wherein the fluid pressure system comprises a syringe pump.

8. The method of claim 1, wherein a diameter of the inner lumen of the tube is between approximately 0.01 inches and approximately 0.04 inches.

5. A method for reducing contamination risk in drawing fluid from vasculature, the system comprising:

providing a tube configured to connect to a multi-lumen catheter, the multi-lumen catheter having;

a proximal port comprising an independent lumen that provides a fluid path between an extracorporeal opening and an intravascular opening that is positioned upstream when the multi-lumen catheter is inside a vessel having a fluid flow;

a distal port comprising an independent lumen that provides a fluid path between the extracorporeal opening and the intravascular opening that is positioned downstream from the proximal port when the multi-lumen catheter is inside a vessel having a fluid flow; and

a medial port comprising an independent lumen that provides a fluid path between the extracorporeal opening and the intravascular opening that is positioned between the proximal port and the distal port;

the distal and medial ports each configured to allow infusion of an infusate into the vessel from their intravascular openings downstream from the intravascular opening of the proximal port;

the tube configured to connect to the proximal port of the multi-lumen catheter without leaking, the tube having an inner lumen that is smaller than the inner lumen of the independent lumen of the proximal port;

providing a fluid pressure system in fluid communication with the inner lumen of the tube;

providing an automated system configured to automatically control the fluid pressure system and create a pressure in the inner lumen that is less than 10 psi and/or provide a flow rate of between approximately 1 and 10 ml per minute such that the amount of contaminating infusate that is drawn into the intravascular opening of the proximal port is limited to less than 10 part per million.

9. Apparatus for improving measurement accuracy in an analyte monitoring system and reducing fluid contamination risk, the apparatus comprising:

a fluid passage having a tip configured to mate with a multi-lumen catheter without leaking, the multi-lumen catheter having;

a proximal port communicating with a proximal port lumen that provides a fluid path to a proximal intravascular opening that is configured to open into a vessel having a fluid flow; and

a distal port communicating with a distal port lumen that is independent from and not in fluid communication with the proximal port lumen and that provides a fluid path to a distal intravascular opening that is configured to open into the vessel distal of and downstream from the proximal intravascular opening to infuse infusates;

a fluid pressure system in fluid communication with the fluid passage, the fluid pressure system configured to periodically automatically draw fluid from the vessel through the proximal intravascular opening and the proximal port and through the tip back into the fluid passage while maintaining a low pressure and/or flow rate to thereby reduce risk of reversing the fluid flow in the vessel and drawing infusates back upstream into the proximal intravascular opening; and

an analyzer configured to automatically analyze at least a portion of the drawn fluid, automatically achieving higher accuracy analysis at least in part as a result of the low pressure and/or flow rate at which the fluid was drawn.

10. The apparatus of claim 9, further configured to reduce dilution errors due to withdrawal of infusates such that infusate does not cause more than a 20% difference in accuracy of an analyte reading that uses fluid drawn into the intravascular opening of the proximal port.

11. The apparatus of claim 9, wherein the fluid passage has an inner diameter of between approximately 0.01 inches and approximately 0.04 inches.

12. The apparatus of claim 9, wherein the fluid pressure system comprises a controller and a pressure monitor that provides feedback to the controller, the controller configured to maintain the withdrawal pressure below 99% of the pressure of blood in the vessel.

13. The apparatus of claim 12, further comprising a patient blood pressure monitor that provides feedback to the controller to allow a baseline for comparison to the withdrawal pressure.

14. The apparatus of claim 12, wherein the pressure monitor is configured to monitor the pressure at or near the proximal port.

15. The apparatus of claim 9, wherein the fluid pressure system is configured to maintain a constant rate for the majority of the time blood is being withdrawn through the proximal port.

16. The apparatus of claim 9, wherein the fluid pressure system is configured to adjust the withdrawal rate to be lower when infusates are being infused through the distal port.

17. A method for automatically drawing high quality blood samples to improve periodic blood analysis and reduce contamination risk, the method comprising:

providing a tube configured to connect to a multi-lumen catheter without leaking, the multi-lumen catheter having an upstream port and a downstream port, each port having an independent lumen not in fluid communication with the other;

positioning the multi-lumen catheter in a patient'"'"'s vessel such that the lumen of the upstream port opens into the vessel upstream of the lumen of the downstream port;

providing an automated fluid pressure system configured to automatically maintain a low pressure and/or flow rate while drawing blood;

connecting the automated fluid pressure system to the tube such that the system is in fluid communication with the upstream port and blood flow in the patient'"'"'s vessel; and

using the automated fluid pressure system to periodically draw blood in through the lumen of the upstream port while maintaining a low pressure and/or flow rate, thereby avoiding a reversal of blood flow in the patient'"'"'s vessel and reducing the risk of contamination of a blood sample.

18. The method of claim 17, wherein infusate is infused into the vessel through the downstream port, the method further comprising reducing the amount of infusate drawn into the lumen of the upstream catheter so that infusate does not cause more than a 20% difference in accuracy of an analyte reading of the blood drawn into the tube as compared to a reading of blood drawn when no infusate is being infused into the vessel.

19. The method of claim 17, wherein the automated fluid pressure system comprises a syringe pump.

20. The method of claim 17, wherein infusate is periodically infused into the vessel through the downstream port, the method further comprising using the automated fluid pressure system to reduce the pressure and/or flow rate of withdrawn blood when infusion of infusate and blood withdrawal occur simultaneously.

21. The method of claim 17, further comprising determining the patient'"'"'s blood pressure and using the automated fluid pressure system to maintain a withdrawal pressure that is less than the patient'"'"'s blood pressure, thereby avoiding reversal of blood flow in the vessel.