Sensors for detecting substances in bodily fluids

• US 9,044,182 B2
• Filed: 03/14/2013
• Issued: 06/02/2015
• Est. Priority Date: 11/16/2005
• Status: Active Grant

• Current Assignee: James H. Silver
• Original Assignee: James H. Silver
• Inventors: Silver, James H.
• Primary Examiner(s): Foley, Shanon A
• Application Number:
  US13/804,184
• Publication Number:
  US 20130202721A1
• Time in Patent Office: 810 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/14528 invasively
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/14557 specially adapted to extracorporeal circuits
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/14735 comprising an immobilised reagent
• CPC Class Codes: A61B 5/1477 non-invasive
• 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 5/4076 Diagnosing or monitoring particular conditions of the nervous system A61B5/4821, A61B5/4824 take precedence
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61B 5/413 Monitoring transplanted tissue or organ, e.g. for possible rejection reactions after a transplant
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/6862 Stents
• CPC Class Codes: A61B 5/6876 Blood vessel
• CPC Class Codes: A61B 5/6882 : Anchoring means
• CPC Class Codes: A61F 2/82 : Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2250/0001 : Means for transferring electromagnetic energy to implants
• CPC Class Codes: G01N 33/84 : involving inorganic compounds or pH
• CPC Class Codes: Y10T 436/177692 : Oxides of nitrogen

Abstract

A system is disclosed that extracts bodily fluid to a reaction chamber for monitoring a substance or property of the patient fluid. In one embodiment, a pump is used to advance the sample of bodily fluid through a filter to produce a filtrate. Another pump advances filtrate into the reaction chamber, while another pump advances reactant into the reaction chamber. A sensor in communication with the reaction chamber determines a concentration of nitric oxide or one of its metabolic products. Methods are also disclosed.

Claims

1. A method of treating a patient with nitrite, the method comprising:

administering nitrite or nitric oxide to the patient;

monitoring a level of nitrite within blood of the patient, the monitoring comprising;

contacting a sensor with the blood of the patient;

excluding particles with a molecular weight greater than 60 kD from a vicinity around the sensor using a size-exclusion filter;

converting nitrite ions included in the vicinity around the sensor to nitric oxide; and

measuring a concentration of nitric oxide using the sensor.

2. The method of claim 1, further comprising using the concentration of nitric oxide to determine a level of nitrite within the blood of the patient.

3. The method of claim 1, further comprising modifying an amount of nitrite or nitric oxide administered to the patient based on the concentration of nitric oxide measured.

4. The method of claim 1, further comprising modifying an amount of nitrite or nitric oxide administered to the patient based on the level of nitrite within the blood of the patient.

5. The method of claim 1, wherein monitoring the level of nitrite within blood of the patient further comprises inserting the sensor within the patient.

6. The method of claim 1, wherein monitoring the level of nitrite occurs as the blood is extracted from the patient.

7. The method of claim 1 wherein excluding particles with a molecular weight greater than 60 kD from the vicinity around the sensor comprises excluding cells and proteins from the vicinity around the sensor.

8. The method of claim 1, wherein converting nitrite ions included in the vicinity around the sensor to nitric oxide comprises applying a constant voltage to the vicinity around the sensor.

9. The method of claim 8, wherein converting nitrite included in the vicinity around the sensor to nitric oxide comprises applying a voltage of about 1.2 V, referenced to a normal hydrogen electrode, to the vicinity around the sensor.

10. The method of claim 1, wherein converting nitrite included in the vicinity around the sensor to nitric oxide comprises reacting nitrite with dilute acid, reducing the nitrite to nitric oxide.

11. The method of claim 10, further comprising containing the dilute acid within the vicinity around the sensor.

12. The method of claim 11, wherein containing the dilute acid within the vicinity around the sensor comprises using an anion-exchange membrane.

13. The method of claim 12, further comprising providing an electromotive force to increase a rate of nitrite diffusing across the anion-exchange membrane.

14. The method of claim 13, wherein providing the electromotive force comprises positioning an anode between the anion-exchange membrane and the size-exclusion filter and positioning a cathode within the anion-exchange membrane and applying a voltage to the anode and cathode.

15. The method of claim 14, wherein applying the voltage to the anode and the cathode comprises applying a constant voltage.

16. The method of claim 14, wherein applying the voltage to the anode and the cathode comprises applying a varying voltage.

17. The method of claim 1, further comprising triggering an alarm if the concentration of nitric oxide is outside a particular range.

18. The method of claim 1, further comprising triggering an alarm if a rate of change of nitric oxide concentration exceeds a particular rate.

19. The method of claim 1, further comprising modifying an amount of nitric or nitric oxide administered to the patient based on a rate of change of nitric oxide concentration.

20. The method of claim 1, further comprising modifying an amount of nitric or nitric oxide administered to the patient based on a rate of change of the level of nitrite.