Devices and methods for detecting and treating inadequate tissue perfusion

• US 20060253160A1
• Filed: 07/12/2006
• Published: 11/09/2006
• Est. Priority Date: 03/12/2003
• Status: Active Grant

• Current Assignee: Data Sciences U K Limited (International Business Machines Corporation)
• Original Assignee: Transoma Medical, Inc.
• Inventors: Benditt, David G., Wilson, Richard R., Brockway, Brian P.
• Granted Patent: US 7,967,758 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36564 controlled by blood pressure
• CPC Class Codes: A61N 1/36571 controlled by blood flow rate, e.g. blood velocity or cardiac output
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

Devices and methods for detecting inadequate tissue perfusion by measuring a parameter other than heart rate such as vascular blood pressure, intracardiac blood pressure, vascular blood flow or tissue perfusion, in addition to or as a substitute for heart rate. Such devices and methods improve the accuracy of determining when and to what degree therapy should be administered to treat inadequate tissue perfusion, such as pre-syncope, syncope, or orthostatic hypotension, particularly in the absence of abnormal cardiac function.

Claims

1. A medical method for detecting and treating inadequate tissue perfusion of a patient, comprising:

providing a sensor for measuring an intravascular blood parameter;

positioning the sensor on a portion of the patient'"'"'s vasculature;

measuring the intravascular parameter using the sensor;

detecting inadequate tissue perfusion based on the intravascular parameter measured by the sensor;

delivering a stimulus to increase tissue perfusion as a function of the measured intravascular parameter.

2. A medical method as in claim 1, wherein the sensor measures blood pressure, and wherein the sensor is positioned on a blood vessel.

3. A medical method as in claim 2, wherein the sensor includes a transducer and a catheter, wherein the catheter extends through a wall and inside a lumen of the blood vessel and the transducer resides outside the blood vessel.

4. A medical method as in claim 1, wherein the sensor measures blood flow rate, and wherein the sensor is positioned on a blood vessel.

5. A medical method as in claim 1, wherein the sensor is positioned on an artery.

6. A medical method as in claim 1, wherein the sensor is positioned on an vein.

7. A medical method for detecting and treating inadequate tissue perfusion of a patient, comprising:

providing a sensor for measuring intracardiac pressure;

positioning the sensor in or on the patient'"'"'s heart;

measuring intracardiac pressure of the left side of the patient'"'"'s heart using the sensor;

detecting inadequate tissue perfusion based on the intracardiac pressure measurement;

delivering a stimulus to increase tissue perfusion as a function of the intracardiac pressure measurement.

8. A medical method as in claim 7, wherein the measured intracardiac pressure comprises left atrial pressure.

9. A medical method as in claim 7, wherein the measured intracardiac pressure comprises left ventricular pressure.

10. A medical method as in claim 7, wherein the sensor is positioned on a chamber wall.

11. A medical method as in claim 10, wherein the chamber wall comprises a septal wall.

12. A medical method as in claim 10, wherein the chamber wall comprises a free wall.

13. A medical method as in claim 10, wherein the sensor includes a transducer and a catheter, wherein the catheter extends through the chamber wall into a cardiac chamber and the transducer resides outside the chamber.

14. A medical method as in claim 13, wherein the sensor is connected to a pacing electrode and the pacing electrode contacts the chamber wall.

15. A medical method for detecting and treating inadequate tissue perfusion of a patient, comprising:

providing a sensor for measuring tissue perfusion;

providing a therapeutic device for delivering a stimulus to increase tissue perfusion;

positioning the sensor in the patient remote from the therapeutic device;

measuring tissue perfusion using the sensor;

detecting inadequate tissue perfusion based on the tissue perfusion measurement; and

delivering a stimulus to increase tissue perfusion as a function of the tissue perfusion measurement.

16. A medical method as in claim 15, wherein the sensor is positioned adjacent vascularized tissue and measures blood flow in the vascularized tissue.

17. A medical method as in claim 16, wherein the sensor measures blood flow in capillaries in the vascularized tissue.

18. A medical method for treating a patient, comprising:

detecting heart rate as an indicator of inadequate tissue perfusion;

detecting at least one other indicia of inadequate tissue perfusion;

delivering a stimulus to increase tissue perfusion as a function of both heart rate and the at least one other indicia.

19. A medical method as in claim 18, further comprising providing a therapeutic device for delivering the stimulus to increase tissue perfusion.

20. A medical method as in claim 19, wherein the step of delivering the stimulus comprises delivering a stimulus to increase heart rate.

21. A medical method as in claim 20, wherein the step of providing a therapeutic device comprises providing a pacemaker, and wherein the step of delivering the stimulus to increase heart rate comprises delivering electrical impulses to the patient'"'"'s heart.

22. A medical method as in claim 20, wherein the step of providing a therapeutic device comprises providing an infusion pump, and wherein the step of delivering the stimulus to increase heart rate comprises delivering a bolus of a drug.

23. A medical method as in claim 20, wherein the step of detecting at least one other indicia of inadequate tissue perfusion comprises detecting blood pressure.

24. A medical method as in claim 23, wherein the step of detecting blood pressure comprises detecting vascular blood pressure.

25. A medical method as in claim 23, wherein the step of detecting blood pressure comprises detecting intracardiac blood pressure.

26. A medical method as in claim 20, wherein the step of detecting at least one other indicia of inadequate tissue perfusion comprises detecting blood flow.

27. A medical method as in claim 26, wherein the step of detecting blood flow comprises detecting vascular blood flow.

28. A medical method as in claim 20, wherein the step of detecting at least one other indicia of inadequate tissue perfusion comprises detecting blood perfusion in tissue.

29. A medical method as in claim 28, wherein the step of detecting blood perfusion in tissue comprises detecting blood perfusion in tissue in the patient'"'"'s upper body.

30. A medical method as in claim 28, wherein the step of detecting blood perfusion in tissue comprises detecting blood perfusion in tissue in the patient'"'"'s chest.

31. A medical method as in claim 28, wherein the step of detecting blood perfusion in tissue comprises detecting blood perfusion in tissue in the patient'"'"'s head or neck.

32. A medical method, comprising:

providing an implantable therapeutic device (ITD) configured to deliver a stimulus to increase heart rate;

providing an implantable pressure sensing device (PSD) including a hermetically sealed housing, a pressure transducer disposed in the housing, a pressure transmission catheter (PTC) having a proximal end, a distal end, and a lumen extending therethrough, with the proximal end of the PTC connected to the housing and the lumen of the PTC in fluid communication with the pressure transducer;

implanting the ITD in a patient;

implanting the PSD in the patient such that the distal end of the PTC resides in a vascular lumen and the housing remains outside the vascular lumen;

connecting the PSD to the ITD via an electrical lead; and

operating the ITD to deliver the stimulus to increase heart rate in response to a drop in blood pressure as measured by the PSD.

33. A method as in claim 32, wherein the pressure transducer of the PSD converts a pressure signal to an electrical signal, and wherein the ITD includes a signal processor which evaluates the electrical signal for hypotension.

34. A method as in claim 33, wherein the lumen of the PTC is filled with a fluid and a barrier is disposed in a distal end of the PTC lumen to contain the fluid while permitting pressure to be transferred therethrough.

35. A method as in claim 32, wherein the ITD delivers an electrical stimulus.

36. A method as in claim 32, wherein the ITD delivers a pharmacological stimulus.