Device for assessing perfusion failure in a patient by measurement of blood flow

• US 7,618,376 B2
• Filed: 10/26/2007
• Issued: 11/17/2009
• Est. Priority Date: 09/23/2003
• Status: Active Grant

• Current Assignee: Vasamed, Inc.
• Original Assignee: Vasamed, Inc.
• Inventors: Kimball, Victor E.
• Primary Examiner(s): Nasser; Robert L
• Application Number:
  US11/924,862
• Publication Number:
  US 20080103378A1
• Time in Patent Office: 753 Days
• Field of Search: None
• US Class Current: 600/485
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/027 using catheters
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• 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 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 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 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61B 5/42 Detecting, measuring or recording for evaluating the gastrointestinal, the endocrine or the exocrine systems A61B1/00, A61B5/4857, A61B5/486, A61B5/4866, A61B5/4869 take precedence
• CPC Class Codes: A61B 5/4233 oesophagus

Abstract

A device is provided for assessing impairment of blood circulation in a patient, such as that in perfusion failure, by measurement of blood flow adjacent a mucosal surface accessible by a mouth or nose and connecting with the gastrointestinal tract or upper respiratory/digestive tract of a patient. The device includes a blood-flow sensor adapted to be positioned adjacent a mucosal surface with a patient'"'"'s body and measuring blood flow in adjacent tissue and a PCO.sub.2 sensor adapted to be positioned adjacent the mucosal surface and measuring PCO.sub.2. In addition a pH sensor may be used in combination with the blood flow determination. A method of detecting perfusion failure is also disclosed. The method includes utilizing blood-flow measurements in conjunction with a surface perfusion pressure index and/or an optical plethysmography index to more accurately assess perfusion failure. These measurements may also be supplement by taking measurements of pH, sublingual PCO.sub.2, and Sa O.sub.2. The invention affords rapid measurement and detection of perfusion failure.

Claims

1. A device for assessing the degree of systemic perfusion in a patient, the device comprising:

a. a surface perfusion pressure monitor for measuring the surface perfusion pressure of a patient; and

b. a blood pressure monitor for measuring the blood pressure of the patient;

wherein the device derives an index from the surface perfusion pressure measurement and the blood pressure measurement to assess the degree of systemic perfusion of the patient.

2. The device of claim 1, wherein the surface perfusion pressure monitor includes a laser Doppler sensor.

3. The device of claim 2 wherein the index derived is a surface perfusion pressure index.

4. The device of claim 1 wherein the surface perfusion pressure monitor includes a photoplethysmograph.

5. The device of claim 4 wherein the index derived is an optical plethysmography index.

6. The device of claim 1 further comprising a blood flow sensor adapted to be positioned adjacent a mucosal surface within a patient'"'"'s body for taking a measurement, directly or indirectly, the measurement selected from the group consisting of sublingual PCO₂, and SaO₂.

7. The device of claim 6 further comprising a sensor for measuring pH.

8. A method for assessing the degree of systemic perfusion in a patient comprising the steps of (i) measuring the surface perfusion pressure in the patient by utilizing a surface perfusion pressure monitor;

(ii) measuring blood pressure in the patient;

(iii) calculating an index with a processor derived from the surface perfusion pressure measurement and the blood pressure measurement; and

(iv) assessing the degree of systemic perfusion of the patient.

9. The method of claim 8 wherein the step of measuring the surface perfusion pressure in a patient includes taking the measurement with a laser Doppler sensor.

10. The method of claim 9 wherein the step of calculating an index derived from the surface perfusion pressure measurement and the blood pressure measurement includes calculating a surface perfusion pressure index.

11. The method of claim 8 wherein the step of measuring the surface perfusion pressure in a patient includes taking the measurement with a photoplethysmograph.

12. The method of claim 11 wherein the step of calculating an index derived from the surface perfusion pressure measurement and the blood pressure measurement includes calculating an optical plethysmography index.

13. The method of claim 8 further comprising the step of (v) taking a blood flow measurement adjacent a mucosal surface accessible by a mouth within a patient'"'"'s body selected from the group consisting of sublingual PCO₂ and SaO₂.

14. The method of claim 13 further comprising the step of (vi) providing a pH sensor for measuring pH.