Tissue profile wellness monitor

• US 10,980,457 B2
• Filed: 02/26/2019
• Issued: 04/20/2021
• Est. Priority Date: 04/21/2007
• Status: Active Grant

• Current Assignee: Masimo Corporation
• Original Assignee: Masimo Corporation
• Inventors: Lamego, Marcelo M.
• Primary Examiner(s): Winakur, Eric F
• Application Number:
  US16/286,393
• Publication Number:
  US 20190254578A1
• Time in Patent Office: 784 Days
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• 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 5/14551 for measuring blood gases
• 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 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/7405 using sound
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• 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
• CPC Class Codes: A61B 5/7475 User input or interface means, e.g. keyboard, pointing device, joystick

Abstract

A tissue profile wellness monitor measures a physiological parameter, generates a tissue profile, defines limits and indicates when the tissue profile exceeds the defined limits. The physiological parameter is responsive to multiple wavelengths of optical radiation after attenuation by constituents of pulsatile blood flowing within a tissue site. The tissue profile is responsive to the physiological parameter. The limits are defined for at least a portion of the tissue profile.

Claims

1. A patient monitor comprising:

a front-end interface configured to receive, from a sensor comprising a light source that emits light into a tissue site of a patient and a detector that detects a plurality of wavelengths of the emitted light after attenuation by the tissue site, a signal indicative of the detected light at each of the plurality of wavelengths; and

a processor configured to;

determine a tissue profile curve across each of the plurality of wavelengths based at least in part on the signal indicative of the detected light at each of the plurality of wavelengths, wherein the tissue profile curve comprises at least a first portion and a second portion;

analyze a shape of the tissue profile curve relative to a predefined boundary curve to determine patient wellness, wherein the first portion is analyzed in comparison to a first portion of the predefined boundary curve, and the second portion is analyzed in comparison to a second portion of the predefined boundary curve; and

output an indication in response to determining the shape of the tissue profile curve exceeds the predefined boundary curve.

2. The patient monitor of claim 1, wherein the indication comprises at least one of a display, an alarm, a diagnostic, or a control.

3. The patient monitor of claim 1, wherein determining the tissue profile curve comprises, at least in part:

measuring, from the signal, values indicative of an amount of light attenuation for at least some of the plurality wavelengths;

defining, based on characteristics of the tissue site, additional values corresponding to at least a portion of a wavelength spectrum between the respective wavelengths associated with the at least some of the plurality of wavelengths; and

combining the measured values at each of the at least some of the plurality wavelengths with the additional values.

4. The patient monitor of claim 1, wherein the processor is further configured to:

output a first signal indicative of patient normalcy when the tissue profile curve is within the predefined boundary curve and a rate of change of the tissue profile curve is less than a maximum rate of change; and

output a second signal indicative of alert when at least a portion of the tissue profile curve is outside of the predefined boundary curve and the rate of change of the tissue profile curve is greater than the maximum rate of change.

5. The patient monitor of claim 1, wherein the tissue profile curve is indicative of at least one of oxygen saturation of the patient, carboxyhemoglobin of the patient, or methemoglobin of the patient.

6. The patient monitor of claim 1, wherein the processor is further configured to:

provide a first indication in response to the first and second portions not exceeding the respective first and second portions of the predefined boundary curve;

provide a second indication in response to one of the first or second portions exceeding the respective first or second portions of the predefined boundary curve; and

provide a third indication in response to both of the first and second portions exceeding the respective first and second portions of the predefined boundary curve.

7. The patient monitor of claim 1, wherein determining the tissue profile curve comprises, at least in part:

determining, at each of the plurality of wavelengths and based on the signal, normalized plethysmographs (NPs); and

normalize each of the determined NPs based on a reference wavelength.

8. The patient monitor of claim 7, wherein the reference wavelength is one of the plurality of wavelengths.

9. A patient monitor comprising:

a front-end interface configured to receive, from a sensor comprising a light source that emits light into a tissue site of a patient and a detector that detects a plurality of wavelengths of the emitted light after attenuation by the tissue site, a signal indicative of the detected light at each of the plurality of wavelengths; and

a processor configured to;

determine a plurality of tissue profile curves over time and based at least in part on the signal indicative of the detected light at each of the plurality of wavelengths, wherein each of the tissue profile curves is across each of the plurality of wavelengths;

evaluate a trend in movement of the tissue profile curves over time relative to a predetermined trend limit to determine patient wellness; and

output an indication in response to determining the trend in movement of the tissue profile curves exceeds the predetermined trend limit.

10. The patient monitor of claim 9, wherein the trend in movement of the tissue profile curve exceeding the predetermined trend limit indicates advance warning of deteriorating patient wellness.

11. The patient monitor of claim 9, wherein determining the tissue profile curve comprises, at least in part:

determining, at each of the plurality of wavelengths and based on the signal, normalized plethysmographs (NPs); and

normalizing each of the determined NPs based on a reference wavelength.

12. The patient monitor of claim 11, wherein the reference wavelength divides the tissue profile curve into a first portion and a second portion, and wherein the first portion is evaluated in relation to a first portion predetermined trend limit, and the second portion is evaluated in relation to a second portion predetermined trend limit.

13. The patient monitor of claim 12, wherein the processor is further configured to:

provide a first indication in response to the first and second portions not exceeding the respective first and second portion predetermined trend limits;

provide a second indication in response to one of the first or second portions exceeding the respective first or second portion predetermined trend limits; and

provide a third indication in response to both of the first and second portions exceeding the respective first and second portion predetermined trend limits.

14. The patient monitor of claim 11, wherein the reference wavelength is one of the plurality of wavelengths.

15. The patient monitor of claim 11, wherein determining the tissue profile curve further comprises, at least in part:

defining continuous normalized NP values corresponding to at least a portion of a wavelength spectrum between the two or more of the plurality of wavelengths based at least in part on characteristics of the tissue site; and

combining the normalized NP values at each of the plurality of wavelengths with the defined continuous normalized NP values.

16. The patient monitor of claim 9, wherein the tissue profile curve is indicative of at least one of oxygen saturation of the patient, carboxyhemoglobin of the patient, or methemoglobin of the patient.