ROBUST FRACTIONAL SATURATION DETERMINATION

• US 20190307377A1
• Filed: 04/17/2019
• Published: 10/10/2019
• Est. Priority Date: 10/13/2011
• Status: Active Grant

• Current Assignee: Masimo Corporation
• Original Assignee: Masimo Corporation
• Inventors: Perea, Philip, Al-Ali, Ammar, Kiani, Massi Joe E.
• Granted Patent: US 11,089,982 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence

Abstract

The present disclosure describes the derivation and measurement of a fractional oxygen saturation measurement. In one embodiment, a system includes an optical sensor and a processor. The optical sensor can emit light of multiple wavelengths directed at a measurement site of tissue of a patient, detect the light after attenuation by the tissue, and produce a signal representative of the detected light after attenuation. The processor can receive the signal representative of the detected light after attenuation and determine, using the signal, a fractional oxygen saturation measurement based on two or more different measures of fractional oxygen saturation.

Claims

1-19. -19. (canceled)

20. A patient monitoring apparatus comprising:

a housing;

a memory device configured to store a signal generated by a noninvasive physiological sensor that monitors a patient, the signal being responsive to a physiological condition of the patient; and

one or more hardware processors in communication with the memory device, the one or more hardware processors being configured to;

determine a carboxyhemoglobin measurement from the signal,

detect a methemoglobin condition for the patient,

responsive to detection of the methemoglobin condition, reduce the carboxyhemoglobin measurement to obtain a reduced carboxyhemoglobin measurement, and

output for presentation a parameter measurement responsive to the reduced carboxyhemoglobin measurement.

21. The patient monitoring apparatus of claim 20, wherein the one or more hardware processors is configured to not reduce the carboxyhemoglobin measurement responsive to not detecting the methemoglobin condition.

22. The patient monitoring apparatus of claim 20, wherein the one or more hardware processors is configured to:

determine another carboxyhemoglobin measurement from the signal, and

use a set carboxyhemoglobin value in place of the another carboxyhemoglobin measurement responsive to not detecting the methemoglobin condition.

23. The patient monitoring apparatus of claim 20, wherein the one or more hardware processors is configured to reduce the carboxyhemoglobin measurement by an amount that depends on a magnitude of the carboxyhemoglobin measurement.

24. The patient monitoring apparatus of claim 20, wherein the one or more hardware processors is configured to determine whether the carboxyhemoglobin measurement reflects a changed condition for the patient or an anomalous measurement.

25. The patient monitoring apparatus of claim 20, wherein the one or more hardware processors is configured to detect the methemoglobin condition from the signal.

26. The patient monitoring apparatus of claim 25, wherein the one or more hardware processors is configured to use a multivariate classifier to detect the methemoglobin condition.

27. The patient monitoring apparatus of claim 25, wherein the one or more hardware processors is configured to:

determine a methemoglobin measurement from the signal, and

detect the methemoglobin condition from a comparison of the methemoglobin measurement and a methemoglobin threshold.

28. The patient monitoring apparatus of claim 20, wherein the one or more hardware processors is configured to determine the parameter measurement from the reduced carboxyhemoglobin measurement, the parameter measurement being indicative of a fractional oxygen saturation.

29. The patient monitoring apparatus of claim 20, further comprising a display configured to present the parameter measurement.

30. The patient monitoring apparatus of claim 20, further comprising the noninvasive physiological sensor, the noninvasive physiological sensor comprising an optical sensor configured to generate the signal.

31. The patient monitoring apparatus of claim 20, wherein the signal is representative of light that is detected after attenuation by tissue of the patient.

32. The patient monitoring apparatus of claim 20, wherein the signal is representative of light of three or more wavelengths that is detected after attenuation by tissue of the patient, and the one or more hardware processors is configured to determine the carboxyhemoglobin measurement from the light of three or more wavelengths that is detected after attenuation.

33. A method of patient monitoring, the method comprising:

generating, by a noninvasive physiological sensor monitoring a patient, a signal responsive to a physiological condition of the patient;

determining, by one or more hardware processors, a carboxyhemoglobin measurement from the signal;

detecting a methemoglobin condition for the patient;

in response to detecting the methemoglobin condition, reducing, by the one or more hardware processors, the carboxyhemoglobin measurement to obtain a reduced carboxyhemoglobin measurement;

determining, by the one or more hardware processors, a parameter measurement from the reduced carboxyhemoglobin measurement; and

presenting, by a display, the parameter measurement.

34. The method of claim 33, further comprising:

determining, by the one or more hardware processors, another carboxyhemoglobin measurement from the signal;

not detecting the methemoglobin condition for the patient; and

in response to not detecting the methemoglobin condition,

not reducing, by the one or more hardware processors, the carboxyhemoglobin measurement, or

using, by the one or more hardware processors, a set carboxyhemoglobin value in place of the another carboxyhemoglobin measurement.

35. The method of claim 33, further comprising detecting the methemoglobin condition from the signal.

36. The method of claim 33, wherein the parameter measurement is a fractional oxygen saturation measurement.

37. The method of claim 33, wherein the signal is representative of light of three or more wavelengths that is detected after attenuation by tissue of the patient, and the carboxyhemoglobin measurement is determined from the light of three or more wavelengths that is detected after attenuation.

38. A patient monitoring apparatus comprising:

a housing;

a memory device configured to store a signal generated by a noninvasive physiological sensor that monitors a patient, the signal being responsive to a physiological condition of the patient; and

one or more hardware processors in communication with the memory device, the one or more hardware processors being configured to;

determine a functional oxygen saturation measurement and a dishemoglobin measurement from the signal,

determine a fractional oxygen measurement from the functional oxygen saturation measurement and the dishemoglobin measurement, and

output for presentation an indicator responsive to the fractional oxygen measurement.

39. The patient monitoring apparatus of claim 38, wherein the one or more hardware processors is configured to:

determine a carboxyhemoglobin measurement and a methemoglobin measurement from the signal, and

determine the dishemoglobin measurement from the carboxyhemoglobin measurement and the methemoglobin measurement.

40. The patient monitoring apparatus of claim 38, wherein the one or more hardware processors is configured to:

determine an accuracy of the functional oxygen saturation measurement or an accuracy of the dishemoglobin measurement, and

prior to determining the fractional oxygen measurement,

change the functional oxygen saturation measurement responsive to the accuracy of the functional oxygen saturation measurement, or

change the dishemoglobin measurement responsive to the accuracy of the dishemoglobin measurement.

41. The patient monitoring apparatus of claim 38, wherein the signal is representative of light of three or more wavelengths that is detected after attenuation by tissue of the patient, and the one or more hardware processors is configured to determine the functional oxygen saturation measurement from the light of three or more wavelengths that is detected after attenuation.

42. The patient monitoring apparatus of claim 38, further comprising a display configured to present the indicator.