System and sensor for early detection of shock or perfusion failure and technique for using the same

• US 8,750,978 B2
• Filed: 12/18/2008
• Issued: 06/10/2014
• Est. Priority Date: 12/31/2007
• Status: Expired due to Fees

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Campbell, Shannon E.
• Primary Examiner(s): SZMAL, BRIAN SCOTT
• Application Number:
  US12/338,797
• Publication Number:
  US 20090171237A1
• Time in Patent Office: 2,000 Days
• Field of Search: 600/547, 600/300, 600/554, 600/593, 600/529, 600/538, 600/485, 600/482, 600/363, 424/439, 424/434, 607/134
• US Class Current: 600/547
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• 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 5/682 Mouth, e.g., oral cavity; tongue; Lips; Teeth

Abstract

According to various embodiments, a system, method, and sensor are provided that is capable of monitoring electrical impedance of oral or nasal mucosal tissue. Such sensors may be appropriate for assessing gut hypoperfusion, gut ischemia, or the onset of shock. The electrical impedance of the oral mucosa or other tissues in the upper respiratory tract may be used to non-invasively assess the clinical state of gastrointestinal tissue.

Claims

1. A system, comprising:

a first electrode configured to apply a current to an oral or nasal mucosa of a patient;

a second electrode configured to detect the applied current from the mucosa and output an impedance measurement related to an electrical impedance of the oral or nasal mucosa; and

a monitor operatively coupled to the first electrode and the second electrode and configured to;

receive a first impedance measurement prior to a surgical procedure and perform an operation on the first impedance measurement to determine a baseline impedance value;

receive a second impedance measurement after or during the surgical procedure and perform the operation on the second impedance measurement to determine an impedance value;

compare the impedance value to the baseline impedance value to determine when the impedance value varies from the baseline impedance value; and

determine that a patient has a clinical condition comprising gut hypoperfusion, gut ischemia, shock, and/or organ failure when the impedance value varies from the baseline impedance value.

2. The system of claim 1, wherein the monitor is configured to determine a rate of change of the impedance value over a time period, wherein the rate of change is utilized to determine the clinical condition when the rate of change exceeds a rate of change of the baseline impedance value.

3. The system of claim 1, wherein the monitor is configured to trigger an alarm when the clinical condition is determined.

4. The system of claim 1, wherein the monitor is configured to receive a plurality of first impedance measurements during a time period prior to the surgical procedure, and wherein the plurality of first impedance measurements are used to determine a plurality of baseline impedance values.

5. The system of claim 4, wherein the plurality of baseline impedance values are used to compute a mean baseline impedance value.

6. The system of claim 5, wherein the monitor is configured to trigger an alarm when the impedance value varies from mean baseline impedance value.

7. A monitor, comprising:

a processor configured to execute instructions stored on a computer readable memory;

wherein the processor is configured to;

determine a baseline impedance value from a first impedance measurement from an oral or nasal mucosa of a patient, wherein the first impedance value is acquired before a surgical procedure;

determine an impedance value from a second impedance measurement from the oral or nasal mucosa of the patient, wherein the second impedance measurement is acquired after or during the surgical procedure;

compare the impedance value to the baseline impedance value to determine when the impedance value varies from baseline impedance value; and

determine that the patient has a clinical condition comprising gut hypoperfusion, gut ischemia, shock, and/or organ failure when the impedance value varies from the baseline impedance value.

8. The monitor of claim 7, wherein the processor is configured to determine a rate of change of the impedance value over a time period, wherein the rate of change is utilized to determine the clinical condition when the rate of change exceeds a rate of change of the baseline impedance value.

9. The monitor of claim 7, wherein the processor is configured to trigger an alarm when the impedance value varies from the baseline impedance value by more than a predetermined percentage change.

10. The monitor of claim 7, wherein the processor is configured to receive a plurality of first impedance measurements during a time period prior to the surgical procedure, and wherein the plurality of first impedance measurements are used to determine a plurality of baseline impedance values.

11. The monitor of claim 10, wherein the plurality of baseline impedance values are used to compute a mean baseline impedance value.

12. The monitor of claim 7, comprising a display configured to provide an indication of the clinical condition.