Systems and methods to reduce fluid contamination

• US 9,848,821 B2
• Filed: 06/16/2011
• Issued: 12/26/2017
• Est. Priority Date: 06/17/2010
• Status: Expired due to Fees

• Current Assignee: OptiScan Biomedical Corporation
• Original Assignee: OptiScan Biomedical Corporation
• Inventors: Rule, Peter, Braig, James R., Keenan, Richard, Callicoat, David N.
• Primary Examiner(s): Hoekstra, Jeffrey G
• Assistant Examiner(s): ABOUELELA, MAY A
• Application Number:
  US13/162,315
• Publication Number:
  US 20110313318A1
• Time in Patent Office: 2,385 Days
• Field of Search: 600345, 600573, 600581, 600582, 604327, 604544, 604508
• 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. 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 wherein the multi-lumen cathether is configured to be staggered such that the proximal intravascular opening and the distal intravascular opening are spaced apart from each other with the distal intravascular opening being 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 comprising a controller, 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, the fluid pressure system configured to automatically draw fluid from the vessel at a rate that is between 1 mL/minute and 10 mL/minute, thereby maintaining the low pressure below the pressure of blood in the vessel, wherein the fluid pressure system is also configured to maintain the low pressure and/or flow rate while drawing at least 2 ml of fluid from the vessel over a draw period that is at least 15 seconds; 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.

2. The apparatus of claim 1, further configured to reduce dilution errors due to withdrawal of infusates such that infusate does not cause more than a 3% difference in accuracy of an analyte reading that uses fluid drawn into the intravascular opening of the proximal port.

3. The apparatus of claim 1, wherein the fluid passage has an inner diameter of between 0.01 inches and 0.04 inches.

4. The apparatus of claim 1, wherein the fluid pressure system comprises a pressure monitor that provides feedback to the controller, the controller configured to maintain the low pressure below 99% of the pressure of blood in the vessel.

5. The apparatus of claim 4, further comprising a patient blood pressure monitor that provides feedback to the controller to allow a baseline for comparison to the low pressure.

6. The apparatus of claim 4, wherein the pressure monitor is configured to monitor the low pressure at or near the proximal port.

7. The apparatus of claim 1, wherein the fluid pressure system is configured to maintain the low pressure and/or flow rate while drawing fluid from the vessel when infusates are being infused through the distal port.

8. The apparatus of claim 1, wherein the controller is configured to maintain the low pressure between 1 psi and 10 psi.