Systems and methods of pH tissue monitoring

• US 20030040665A1
• Filed: 05/02/2002
• Published: 02/27/2003
• Est. Priority Date: 05/28/1999
• Status: Abandoned Application

• Current Assignee: Boston VA Research Institute
• Original Assignee: E-Monitors, Inc.
• Inventors: Treanor, Patrick, Khuri, Shukri F.
• Application Number:
  US10/137,709
• Publication Number:
  US 20030040665A1
• Time in Patent Office: Days
• US Class Current: 600/345
• 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 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/413 Monitoring transplanted tissue or organ, e.g. for possible rejection reactions after a transplant
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61M 1/3613 Reperfusion, e.g. of the coronary vessels, e.g. retroperfusion
• CPC Class Codes: A61M 1/3621 Extra-corporeal blood circuits single-needle circuits A61M1/30
• CPC Class Codes: A61M 1/3664 for preparing cardioplegia solutions

Abstract

The invention relates to the use of pH measurements of tissue as a system for controlling diagnostic and/or surgical procedures. The invention also relates to an apparatus used to perform tissue pH measurements. Real time tissue pH measurements can be used as a method to determine ischemic segments of the tissue and provide the user with courses of conduct during and after a surgical procedure. When ischemia is found to be present in a tissue, a user can effect an optimal delivery of preservation fluids to the site of interest and/or effect a change in the conduct of the procedure to raise the pH of the site. A preferred embodiment includes a method of detecting acidosis in tissue comprising the steps of contacting the tissue of a patient with a first pH electrode disposed in an anterior wall of the left ventricle, and further contacting the tissue of the patient with a second pH electrode disposed in a posterior wall of the left ventricle.

Claims

1. A method of detecting acidosis in tissue comprising the steps of:

contacting tissue of a patient with a first pH electrode disposed in an anterior wall of a left ventricle;

contacting tissue of the patient with a second pH electrode disposed in a posterior wall of the left ventricle;

measuring the pH of the tissue with the first and second electrode during cardiac surgery;

monitoring the pH of the tissue with the first and second electrode during cardiac surgery;

determining if the tissue pH falls below a threshold level indicative of acidosis with the first and second electrode; and

determining a post-operative outcome based on the threshold level and the tissue pH measured by the first and second electrode.

2. The method of claim 1, wherein the threshold level indicative of adverse acidosis during a period of aortic clamping is below 6.8.

3. The method for detecting acidosis of claim 1, further comprises the step of controlling acidosis by delivering a preservation solution to a heart at a plurality of sites.

4. The method for detecting acidosis of claim 3, wherein the step of delivering a preservation solution to a heart further comprises the step of altering the flow rate of the preservation solution.

5. The method for detecting acidosis of claim 3, wherein the step of delivering a preservation solution to a heart further comprises the step of altering the temperature of the preservation solution.

6. The method for detecting acidosis of claim 3, wherein the step of delivering a preservation solution to a heart further comprises the step of altering the site of delivery of the preservation solution.

7. The method for detecting acidosis of claim 3, wherein the step of delivering a preservation solution to a heart further comprises the step of repositioning a tip of a catheter which delivers the solution.

8. The method for detecting acidosis of claim 3, wherein the step of delivering a preservation solution to a heart further comprises the step of directing the solution through a manifold.

9. The method for detecting acidosis of claim 3, wherein the step of delivering a preservation solution to a heart further comprises the step of applying direct coronary artery pressure on a proximal portion of the artery.

10. The method for detecting acidosis of claim 3, wherein the step of delivering a preservation solution to a heart further comprises the step of occluding an orifice of a left main coronary artery.

11. The method for detecting acidosis of claim 3, wherein the step of delivering a preservation solution to a heart further comprises the step of inflating a balloon of a retrograde coronary sinus catheter.

12. The method for detecting acidosis of claim 3, wherein the step of delivering a preservation solution to a heart further comprises the step of administering a bolus of preservation solution through an orifice of a right coronary artery.

13. The method of detecting acidosis of claim 1, wherein the monitoring the pH comprises calculating an integrated mean value of pH measured with the first and the second electrode.

14. A method of correcting acidosis at a site of interest in myocardial tissue comprising the steps of:

intercontacting an anterior wall in the myocardial tissue of a patient with a first pH electrode located in the anterior wall, and with a second pH electrode located in the posterior wall and a temperature sensor during cardiac surgery;

measuring the pH and the temperature of the anterior wall and posterior wall;

determining if the pH of the anterior and the posterior wall falls below a threshold level indicative of acidosis; and

delivering a preservation solution to a heart to raise the pH of the anterior wall and the posterior wall in the myocardial tissue if the pH falls below the threshold level indicative of acidosis.

15. The method for correcting acidosis of claim 14, wherein the pH of a site of interest in the myocardial tissue is raised more than 0.1 pH unit.

16. The method for correcting acidosis of claim 14, wherein the step of delivering the preservation solution to a heart further comprises the step of altering the flow rate of the preservation solution.

17. The method for correcting acidosis of claim 14, wherein the step of delivering the preservation solution to a heart further comprises the step of altering the temperature of the preservation solution.

18. The method for correcting acidosis of claim 14, wherein the step of delivering the preservation solution to a heart further comprises the step of altering the site of delivery of the preservation solution.

19. The method for correcting acidosis of claim 14, wherein the step of delivering the preservation solution to a heart further comprises the step of repositioning the tip of the catheter which delivers the solution.

20. The method for correcting acidosis of claim 14, wherein the step of delivering the preservation solution to a heart further comprises the step of applying direct coronary artery pressure on a proximal portion of the artery.

21. The method for correcting acidosis of claim 14, wherein the step of delivering the preservation solution to a heart further comprises the step of occluding an orifice of a left main coronary artery.

22. The method for correcting acidosis of claim 21, wherein the step of occluding an orifice of a left main coronary artery is performed using a balloon catheter.

23. The method for correcting acidosis of claim 14, wherein the step of delivering the preservation solution to a heart further comprises the step of inflating a balloon of a retrograde coronary sinus catheter.

24. The method for correcting acidosis of claim 14, wherein the step of delivering the preservation solution to a heart further comprises the step of administering a bolus of preservation solution through an orifice of a right coronary artery.

25. The method for correcting acidosis of claim 14, further comprising the step of assessing the adequacy of coronary revascularization following a heart surgery procedure.

26. The method for correcting acidosis of claim 14 further comprising the step of identifying viable but nonfunctioning heart muscle.

27. The method for correcting acidosis of claim 14, further comprising the step of monitoring the pH of the heart muscle post-operatively.

28. The method of correcting acidosis of claim 14, wherein the step of measuring the pH further comprises calculating an integrated mean pH during a surgical procedure at the anterior wall and posterior wall.

29. The method of correcting acidosis of claim 14, wherein the step of measuring the pH comprises measuring the pH at the end of a reperfusion process.