Method of monitoring an automated point-of-care fluid testing system

• US 8,317,698 B2
• Filed: 08/24/2010
• Issued: 11/27/2012
• Est. Priority Date: 08/31/2009
• Status: Active Grant

• Current Assignee: ICU Medical Incorporated
• Original Assignee: Hospira Incorporated (Pfizer Inc.)
• Inventors: Lowery, Michael G.
• Primary Examiner(s): Fuller, Rodney
• Application Number:
  US12/862,150
• Publication Number:
  US 20110054276A1
• Time in Patent Office: 826 Days
• Field of Search: 600/309
• US Class Current: 600/309
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• 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 5/150358 Strips for collecting blood, e.g. absorbent optical reagent test strips G01N21/8483; chemical reagent test strips G01N33/4875, G01N33/52
• CPC Class Codes: A61B 5/15087 short range, e.g. between console and disposable using implanted devices A61B5/150877
• CPC Class Codes: A61B 5/150961 Means for the detection of the presence or absence of a module, a component or an abnormal condition; detection of leaks
• 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 5/155 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: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 39/12 for joining a flexible tube to a rigid attachment
• CPC Class Codes: A61M 5/14228 with linear peristaltic action, i.e. comprising at least three pressurising members or a helical member

Abstract

A method of monitoring performance of a fluid testing system is provided. The method draws a fluid sample to the testing system using a pump. A voltage output of a sensor, such as an optical sensor, is generated. The voltage output of the optical sensor during the drawing is compared to an upper fluid volume drawn based voltage limit and a lower fluid volume drawn based voltage limit stored within a memory. The system is flushed with a flushing fluid using the pump to flush the flushing fluid from the testing system. The voltage output of the optical sensor during the flushing is compared to an upper fluid volume flushed based voltage limit and a lower fluid volume flushed based voltage limit stored within the memory. An alert generates if at least one of the voltage output during the drawing of the fluid sample is outside of voltage limits.

Claims

1. A method of monitoring performance of a fluid testing system having a sensor, a patient connection adapted to connect the system to a patient to collect a fluid sample, a pump, a processor in communication with a memory, and a flushing fluid connection adapted to connect the system to a flushing fluid to flush the system after a fluid test, the method comprising:

drawing a fluid sample from the patient via the patient connection using a pump of the testing system to draw the fluid sample from the patient to the testing system;

generating a voltage output of a sensor indicative of a fluid present at the sensor;

comparing the voltage output of the sensor during the drawing of the fluid sample to an upper fluid volume drawn based voltage limit and a lower fluid volume drawn based voltage limit stored within a memory in communication with a processor;

flushing the system with a flushing fluid using the pump of the testing system to flush the flushing fluid from the testing system;

comparing the voltage output of the sensor during the flushing of the flushing fluid to an upper fluid volume flushed based voltage limit and a lower fluid volume flushed based voltage limit stored within the memory in communication with the processor; and

generating an alert if at least one of the voltage output during the drawing of the fluid sample is outside of the lower fluid volume drawn based voltage limit and the upper volume drawn based voltage limit and the voltage output during the flushing of the flushing fluid is outside of the lower fluid volume flushed based voltage limit and the upper fluid volume flushed based voltage limit.

2. The method of claim 1, wherein the upper fluid volume drawn based voltage limit is generated using a forward exponential moving average of the voltage output of the sensor.

3. The method of claim 1, wherein the lower fluid volume drawn based voltage limit is a generated using a reverse exponential moving average of the voltage output of the sensor.

4. The method of claim 1, wherein the upper fluid volume flushed based voltage limit is a generated using a reverse exponential moving average of the voltage output of the sensor.

5. The method of claim 1, wherein the upper fluid volume flushed based voltage limit is a generated using a forward exponential moving average of the voltage output of the sensor.

6. The method of claim 1, wherein the alert indicates at least one of an occlusion during the drawing the fluid sample, an occlusion during the flushing the system, presence of air in the system, and a pump rate malfunction.

7. The method of claim 1, wherein the upper fluid volume drawn based voltage limit and the lower fluid volume drawn based voltage limit stored within the memory are generated on the fluid testing system.

8. The method of claim 1, wherein the upper fluid volume flushed based voltage limit and the lower fluid volume flushed based voltage limit stored within the memory are generated on the fluid testing system.

9. The method of claim 1, wherein the step of generating a voltage output of a sensor is done by an optical sensor disposed in the testing system.

10. The method of claim 1, wherein during one of the drawing step and the flushing step the testing system operates the pump at a generally constant pumping rate.

11. A method of generating voltage output limits for a fluid draw of a fluid testing system having an optical sensor, a patient connection adapted to connect the system to a patient to collect a fluid sample, a pump, and a processor in communication with a memory, the method comprising:

drawing a known quantity fluid sample using a pump of the testing system to draw the fluid sample to the testing system;

generating a plurality of voltage outputs of an optical sensor indicative of a fluid present at the optical sensor periodically during the drawing of the fluid sample;

calculating an upper voltage limit utilizing a forward exponential moving average of the plurality of voltage outputs and a positive offset value; and

calculating a lower voltage limit utilizing a reverse exponential moving average of the plurality of voltage outputs and a negative offset value.

12. The method of claim 11, wherein the positive offset value may vary based upon a type of test being performed by the fluid testing system.

13. The method of claim 11, wherein the pump of testing system operates at a generally constant pumping rate during the drawing the known quantity fluid sample.

14. The method of claim 11, wherein the upper voltage limit is a function of volume drawn into the system at a particular time during the drawing.

15. The method of claim 11, wherein the lower voltage limit is a function of volume drawn into the system at a particular time during the drawing.

16. A method of generating voltage output limits for a fluid flush of a fluid testing system having an optical sensor, a patient connection adapted to connect the system to a patient to collect a fluid sample, a pump, and a processor in communication with a memory, the method comprising:

flushing a known quantity of fluid from the fluid testing system using a pump of the testing system to flush the fluid;

generating a plurality of voltage outputs of an optical sensor indicative of a fluid present at the optical sensor periodically during the flushing of the fluid;

calculating an upper voltage limit utilizing a reverse exponential moving average of the plurality of voltage outputs and a positive offset value; and

calculating a lower voltage limit utilizing a forward exponential moving average of the plurality of voltage outputs and a negative offset value.

17. The method of claim 16, wherein the positive offset value may vary based upon a type of test being performed by the fluid testing system.

18. The method of claim 16, wherein the pump of testing system operates at a generally constant pumping rate during the flushing the known quantity of fluid.

19. The method of claim 16, wherein the upper voltage limit is a function of volume flushed from the system at a particular time during the flushing.

20. The method of claim 16, wherein the lower voltage limit is a function of volume flushed from the system at a particular time during the flushing.