Method And System For Determining Vascular Changes Using Plethysmographic Signals

• US 20120197142A1
• Filed: 01/31/2011
• Published: 08/02/2012
• Est. Priority Date: 01/31/2011
• Status: Abandoned Application

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Lovejoy, David, Campbell, Shannon
• Application Number:
  US13/017,462
• Publication Number:
  US 20120197142A1
• Time in Patent Office: Days
• US Class Current: 600/507
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/4848 Monitoring or testing the effects of treatment, e.g. of medication
• CPC Class Codes: A61B 5/4884 inducing physiological or psychological stress, e.g. applications for stress testing

Abstract

Embodiments of the present disclosure relate to determining changes in a vasculature by analyzing changes in one or more attributes of a plethysmographic signal. According to certain embodiments, an apparatus may obtain plethysmographic signals prior to and subsequent to the administration of a vasoactive stimulus. The apparatus may include a processing unit configured to analyze and to compare attributes of the plethysmographic signals. The processing unit may correlate any changes in signal attributes to a change in a physiological condition of the vasculature (e.g., vascular tone/compliance). The apparatus may also include a display unit configured to present any changes in the vasculature as well as any alarms in response to a trigger from the processing unit.

Claims

1. A monitor comprising:

a processing unit configured to;

calculate one or more baseline attributes of a baseline plethysmographic signal obtained from a patient;

compare one or more calculated attributes of a plethysmographic signal to the one or more calculated baseline attributes; and

correlate changes in the one or more calculated attributes from the one or more calculated baseline attributes to a change in vascular compliance; and

a display unit configured to provide an indication of the change in vascular compliance.

2. The monitor of claim 1, wherein the baseline plethysmographic signal or the baseline attributes are obtained from a memory of a sensor.

3. The monitor of claim 1, wherein the baseline plethysmographic signal and the plethysmographic signal comprise continuous wavelet transformed signals.

4. The monitor of claim 1, wherein the attributes of the baseline plethysmographic signal and the plethysmographic signal comprise one or more amplitudes of one or more peaks, a length in duration from a beginning of a systolic phase to an end of a diastolic phase, an area under a curve, a position of a dicrotic notch, slopes of ascending and descending limbs, or movement of the dicrotic notch.

5. The monitor of claim 1, wherein the processing unit is configured to trigger an alarm when the change in vascular compliance exceeds a certain threshold.

6. The monitor of claim 5, wherein the threshold comprises a percent change in the vascular compliance.

7. The monitor of claim 5, wherein the display unit is configured to present the alarm in response to the trigger from the processing unit.

8. The monitor of claim 1, wherein the plethysmographic signal is obtained from the patient after the administration of a vasoactive stimulus.

9. A system comprising:

a sensor capable of generating a physiological signal;

a processing unit configured to;

calculate one or more baseline attributes of a baseline physiological signal obtained from a patient;

compare one or more calculated attributes of a subsequent physiological signal obtained from the patient to the one or more calculated baseline attributes; and

correlate changes in the one or more calculated attributes from the one or more calculated baseline attributes to a change in vascular compliance.

10. The system of claim 9, wherein the baseline physiological signal and the subsequent physiological signal comprise continuous wavelet transformed signals.

11. The system of claim 9, wherein the attributes of the baseline physiological signal and the subsequent physiological signal comprise one or more amplitudes of one or more peaks, a length in duration from a beginning of a systolic phase to an end of a diastolic phase, an area under a curve, a position of a dicrotic notch, slopes of ascending and descending limbs, or movement of the dicrotic notch.

12. The system of claim 9, wherein the processing unit is configured to obtain the baseline physiological signal or the baseline attributes from a memory of the sensor.

13. The system of claim 9, comprising a display unit configured to provide an indication of the change in vascular compliance.

14. The system of claim 9, wherein the processing unit is configured to trigger an alarm when the change in vascular compliance exceeds a certain threshold.

15. The system of claim 14, comprising a display unit configured to present the alarm in response to the trigger from the processing unit.

16. The system of claim 14, wherein the threshold comprises a percent change in the vascular compliance.

17. The system of claim 9, wherein the subsequent physiological signal is obtained from the patient after the administration of a vasoactive stimulus.

18. A method, comprising:

obtaining a baseline plethysmographic signal from a patient;

calculating one or more attributes of the baseline plethysmographic signal;

administering a vasoactive stimulus to the patient;

obtaining a subsequent plethysmographic signal from the patient;

calculating one or more attributes of the subsequent plethysmographic signal;

comparing the one or more calculated attributes of the subsequent plethysmographic signal to the one or more calculated attributes of the baseline plethysmographic signal; and

correlating changes in the one or more calculated attributes to a change in vascular compliance in the patient.

19. The method of claim 18, comprising providing an indication of change in the vascular compliance on a display.

20. The method of claim 18, comprising triggering an alarm when the change in vascular compliance exceeds a certain threshold.