PROBES AND SENSORS FOR ASCERTAINING BLOOD CHARACTERISTICS AND METHODS AND DEVICES FOR USE THEREWITH

• US 20100010328A1
• Filed: 07/11/2008
• Published: 01/14/2010
• Est. Priority Date: 07/11/2008
• Status: Abandoned Application

• Current Assignee: Keimar, Inc.
• Original Assignee: Keimar, Inc.
• Inventors: Corl, Paul Douglas, Nguyen, Harry D., Martin, Jim F., Webber, Margaret R.
• Application Number:
  US12/172,181
• Publication Number:
  US 20100010328A1
• Time in Patent Office: Days
• US Class Current: 600/354
• CPC Class Codes: A61B 2562/0215 Silver or silver chloride containing
• CPC Class Codes: A61B 2562/0217 Electrolyte containing
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/6852 Catheters

Abstract

A probe for use in a patient having a vessel carrying blood to ascertain characteristics of the blood having a cannula adapted to be inserted into the vessel of the patient. The cannula has a length so that when the distal extremity is in the vessel of the patient the proximal extremity is accessible outside of the patient. A gas sensor assembly is carried within the distal extremity of the cannula for determining gas characteristics of the blood in the vessel. A pressure sensor is carried within the distal extremity of the cannula for determining the pressure of the blood in the vessel.

Claims

1. A probe for use in a patient having a vessel carrying blood to ascertain characteristics of the blood, the probe comprising:

a cannula adapted to be inserted into a vessel of a patient and having a proximal extremity and a distal extremity, the cannula having a length so that when the distal extremity is in the vessel of the patient the proximal extremity is accessible outside of the patient;

a gas sensor assembly carried within the distal extremity of the cannula for determining gas characteristics of the blood in the vessel;

a pH sensor assembly carried within the distal extremity of the cannula for determining pH of the blood in the vessel; and

a pressure sensor assembly carried within the distal extremity of the cannula for determining pressure of the blood in the vessel.

2. The probe of claim 1, wherein the pressure sensor assembly comprises a solid state pressure sensor.

3. The probe of claim 1, wherein the distal extremity of the cannula comprises a gas permeable material proximate to the gas sensor assembly.

4. The probe of claim 1, further comprising an electrolyte solution disposed within the cannula, and wherein the gas sensor assembly includes electrodes disposed in the electrolyte solution for providing electrical inputs to and electrical outputs from the gas sensor assembly.

5. The probe of claim 1, wherein the gas sensor assembly comprises an oxygen sensor assembly.

6. The probe of claim 5, wherein the gas sensor assembly further comprises a carbon dioxide sensor assembly.

7. The probe of claim 6, further comprising conductor elements connected to the oxygen sensor assembly and to the carbon dioxide sensor assembly and configured to supply electrical outputs to the proximal extremity of the cannula.

8. The probe of claim 5, wherein the oxygen sensor assembly includes:

an electrolyte fill solution disposed in the cannula; and

first, second, and third electrodes disposed in the electrolyte fill solution and configured to provide electrical outputs to the proximal extremity of the cannula.

9. The probe of claim 1, further comprising a flex circuit assembly extending from the proximal extremity of the cannula to the distal extremity of the cannula, wherein the gas sensor assembly, the pH sensor, and the pressure sensor assembly are mounted on the flex circuit assembly.

10. The probe of claim 1, wherein the gas sensor assembly, the pH sensor assembly, and the pressure sensor assembly are attached to conductor elements of a flex circuit assembly that provides a zero profile connector.

11. The probe of claim 2, combined with a module comprising electronics configured to create and digitize analog signals from the pressure sensor assembly and software algorithms configured to provide measurements of systolic and diastolic blood pressure, mean arterial pressure, heart rate, and systemic vascular resistance.

12. The probe of claim 5, wherein the oxygen sensor assembly comprises a working electrode, a counter electrode, and a reference electrode, and wherein the oxygen sensor assembly has a structure that supports high electrochemical activity between the working electrode and the counter electrode and that inhibits electrochemical activity between the working electrode and the reference electrode.

13. The probe of claim 12, wherein a voltage of each of the working electrode, the counter electrode, and the reference electrode is set relative to the others of the working electrode, the counter electrode, and the reference electrode in order to optimize performance of the oxygen sensor assembly.

14. The reference electrodes probe of claim 12, wherein the reference electrode comprises a AgCl coating on a bare Ag wire.

15. The probe of claim 1, wherein the pressure sensor assembly comprises a pressure sensing element and a pressure sensor chamber that is not perfectly round after the cannula has been pre-treated, due to an internal structure near the pressure sensing element, or both.