SYSTEMS AND METHODS FOR NORMALIZING A PLETHYSMOGRAPH SIGNAL FOR IMPROVED FEATURE ANALYSIS

• US 20130296674A1
• Filed: 06/05/2013
• Published: 11/07/2013
• Est. Priority Date: 09/30/2009
• Status: Abandoned Application

• Current Assignee: Nellcor Puritan Bennett Ireland
• Original Assignee: Nellcor Puritan Bennett Ireland
• Inventors: Watson, James Nicholas, Sethi, Rakesh, Stoughton, Robert, Addison, Paul Stanley
• Application Number:
  US13/911,019
• Publication Number:
  US 20130296674A1
• Time in Patent Office: Days
• US Class Current: 600/324
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B

Abstract

The present disclosure relates to systems and methods for analyzing and normalizing signals, such as PPG signals, for use in patent monitoring. The PPG signal may be detected using a continuous non-invasive blood pressure monitoring system and the normalized signals may be used to determine whether a recalibration of the system should be performed.

Claims

1. A method for normalizing a light intensity signal using a physiological monitoring system, comprising:

receiving, using a processor, a light intensity signal from a subject at a first time;

obtaining, using the processor, information indicating a change in a setting of the monitoring system;

receiving, using a processor, a light intensity signal from a subject at a second time, wherein the first time occurs before the change in the setting of the monitoring system and the second time occurs after the change in the setting of the monitoring system;

normalizing, using the processor, the light intensity signal at the second time in response to the change in the setting of the monitoring system;

comparing, using the processor, the light intensity signal at the first time and the normalized light intensity signal at the second time; and

triggering, using the processor, an action, based at least in part on whether the light intensity signal at the first time and the normalized light intensity signal at the second time correspond.

2. The method of claim 1, wherein normalizing the light intensity signal at the second time comprises performing a calculation based at least in part on a change in amplitude, area, pulse period, baseline, or any combination thereof.

3. The method of claim 1, wherein obtaining information indicating a change in a setting of the monitoring system comprises receiving a user input.

4. The method of claim 1, wherein the action comprises calculating a physiological parameter of the subject.

5. The method of claim 1, wherein the action comprises generating an alarm signal.

6. The method of claim 1, wherein the action comprises generating a recalibration request.

7. The method of claim 1, wherein the comparing comprises comparing a metric of the light intensity signal at the first time and a metric of the normalized light intensity signal at the second time

8. The method of claim 7, wherein the metric comprises:

peak amplitude, area, period, baseline, or any combination thereof.

9. A system for normalizing a light intensity signal in a physiological monitoring system, comprising a processor configured for:

receiving a light intensity signal from a subject at a first time;

obtaining information indicating a change in a setting of the monitoring system;

receiving a light intensity signal from a subject at a second time, wherein the first time occurs before the change in the setting of the monitoring system and the second time occurs after the change in the setting of the monitoring system;

normalizing the light intensity signal at the second time in response to the change in the setting of the monitoring system;

comparing the light intensity signal at the first time and the normalized light intensity signal at the second time; and

triggering an action, based at least in part on whether the light intensity signal at the first time and the normalized light intensity signal at the second time correspond.

10. The system of claim 9, wherein normalizing the light intensity signal at the second time comprises performing a calculation based at least in part on a change in amplitude, area, pulse period, baseline, or any combination thereof.

11. The system of claim 9, wherein obtaining information indicating a change in a setting of the monitoring system comprises receiving a user input.

12. The system of claim 9, wherein the action comprises calculating a physiological parameter of the subject.

13. The system of claim 9, wherein the action comprises generating an alarm signal.

14. The system of claim 9, wherein the action comprises generating a recalibration request.

15. The system of claim 9, wherein the comparing comprises comparing a metric of the light intensity signal at the first time and a metric of the normalized light intensity signal at the second time

16. The system of claim 15, wherein the metric comprises:

peak amplitude, area, period, baseline, or any combination thereof.