Sensors for detecting substances indicative of stroke, ischemia, infection or inflammation

• US 8,609,426 B2
• Filed: 01/26/2012
• Issued: 12/17/2013
• 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:
  US13/359,313
• Publication Number:
  US 20120135531A1
• Time in Patent Office: 691 Days
• Field of Search: None
• US Class Current: 436/116
• 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 assessing vascular status in a patient, the method comprising:

positioning a sensor in communication with a body fluid;

measuring, using the sensor, a concentration of a nitric oxide metabolite in the body fluid;

determining, in a processor, a baseline concentration of the nitric oxide metabolite in the body fluid, based on the measured concentration;

monitoring changes in the concentration of the nitric oxide metabolite in the body fluid from the baseline concentration, wherein the changes are indicative of the vascular status; and

activating a signal in response to a change in the concentration of the nitric oxide metabolite from the baseline concentration by more than a predetermined limit.

2. A method as in claim 1, wherein positioning the sensor comprises positioning the sensor in communication with blood.

3. A method as in claim 1, wherein positioning the sensor comprises positioning the sensor in communication with cerebrospinal fluid.

4. A method as in claim 1, wherein the nitric oxide metabolite comprises an indicator of a presence of nitric oxide in the body fluid, and wherein the metabolite is selected from the group consisting of nitrite and nitrate.

5. A method as in claim 1, wherein activating the signal comprises activating an alarm.

6. A method as in claim 5, wherein activating the alarm comprises activating an alarm selected from the group consisting of an audio alarm, a visual alarm, a tactile feedback alarm and a transmission of information to a remote location.

7. A method as in claim 1, wherein activating the signal comprises activating application of a responsive therapy to the patient.

8. A method as in claim 1, wherein the signal is activated when the change from the baseline concentration is between about 0.01% and about 100% per second.

9. A method as in claim 1, wherein the signal is activated when the change from the baseline concentration is more than about 10% to about 100,000%.

10. A method of assessing vascular status in a patient, the method comprising:

positioning a sensor in communication with a body fluid;

measuring, using the sensor, a concentration of a nitric oxide metabolite in the body fluid;

determining, in a processor, a range of acceptable concentrations of the nitric oxide metabolite in the body fluid, based on the measured concentration;

monitoring changes in the concentration of the nitric oxide metabolite in the body fluid from the measured concentration, wherein the changes are indicative of the vascular status; and

activating a signal in response to a measurement of the concentration of the nitric oxide metabolite that is outside the range of acceptable concentrations.

11. A method as in claim 10, wherein positioning the sensor comprises positioning the sensor in communication with blood.

12. A method as in claim 10, wherein positioning the sensor comprises positioning the sensor in communication with cerebrospinal fluid.