INTERFERENCE DETECTOR FOR PATIENT MONITOR

• US 20110109459A1
• Filed: 07/22/2010
• Published: 05/12/2011
• Est. Priority Date: 07/24/2009
• Status: Active Grant

• Current Assignee: Masimo Corporation
• Original Assignee: Masimo Laboratories, Inc. (Masimo Corporation)
• Inventors: Paul, Mathew, Chen, Jesse, Lamego, Marcelo, Kiani, Massi Joe E., Poeze, Jeroen
• Granted Patent: US 8,471,713 B2
• Time in Patent Office: Days
• US Class Current: 340/573.1
• CPC Class Codes: A61B 2560/0242 adapted to measure environmental factors, e.g. temperature, pollution
• CPC Class Codes: A61B 2560/0276 Determining malfunction
• CPC Class Codes: A61B 5/0015 characterised by features of the telemetry system
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• 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 5/7228 Signal modulation applied to the input signal sent to patient or subject; demodulation to recover the physiological signal modulation H03C
• CPC Class Codes: G01R 13/0281 using electro-optic elements
• CPC Class Codes: G01R 29/0814 Field measurements related to measuring influence on or from apparatus, components or humans EMC, EMI and similar testing in general G01R31/001, e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning

Abstract

A system is disclosed for detecting and calculating the level of ambient and/or environmental noise, such as electromagnetic interference generated by electric power lines, ambient lights, light dimmers, television or computer displays, power supplies or transformers, and medical equipment. In some embodiments, the system performs frequency analysis on the interference signal detected by light photodetectors and determines the power of the interference signal concentrated in the analyzed frequency bands. The worst-case interference level can be determined by selecting the maximum from the computed power values. In some embodiments, the determined interference signal power can be compared with the noise tolerance of a patient monitoring system configured to reliably and non-invasively detect physiological parameters of a user. The results of the comparison can be presented to the user audio-visually. In some embodiments, the system can be used to perform spot check measurements of electromagnetic interference.

Claims

1. A system for detecting interference in a measurement device, the system comprising:

a process configured to determine a level of environmental interference in a measurement device; and

a display for audio or visual indication of the level of environmental interference.

2. The system of claim 1, wherein the audio or visual indication indicates that an amount of environmental interference is acceptable.

3. The system of claim 1, wherein the audio or visual indication indicates that an amount of environmental interference is not acceptable.

4. A noninvasive monitor that receives one or more sensor signals responsive to light attenuated by tissue of a monitored patient and processes the sensor signals to determine measurement values for one or more physiological parameters of said monitored patient, the sensor including a light source and one or more detectors housed in a sensor housing that positions the light source and said detector proximate said tissue, the monitor including a signal processor that determines an amount of ambient electronic interference proximate said sensor, and at least one of an audio or visual indication perceptible by a caregiver of said amount of said interference.

5. The noninvasive monitor of claim 4, wherein said audio of visual indication includes a display, and wherein said signal processor outputs a display signal responsive to said amount of said ambient electronic interference, said display providing a visual cue responsive to said display signal.

6. The noninvasive monitor of claim 5, wherein said visual cue comprises a meter.

7. The noninvasive monitor of claim 6, wherein said monitor includes a memory storing an interference threshold and meter shows said amount of said interference relative said interference threshold.

8. The noninvasive monitor of claim 7, wherein said meter comprises a continuum from low interference to high interference and wherein said threshold is between said low and said high.

9. The noninvasive monitor of claim 8, wherein said meter comprises a bar graph.

10. The noninvasive monitor of claim 8, wherein said meter comprises a moving electronic dial.

11. The noninvasive monitor of claim 8, wherein said meter comprises a series of LEDs.

12. The noninvasive monitor of claim 8, wherein said meter comprises a bar graph.

13. The noninvasive monitor of claim 8, wherein said low is generally associated with green and high is generally associated with red.

14. The noninvasive monitor of claim 4, wherein said signal processor continually determines an amount of ambient electronic interference proximate said sensor when in an interference detection mode thereby allowing a caregiver to change locations and monitor said ambient interference as they move.

15. The noninvasive monitor of claim 4, wherein said audio of visual indication includes a sound transducer, and wherein said signal processor outputs an audio signal responsive to said amount of said ambient electronic interference, said transducer providing an audio cue responsive to said audio signal.

16. A method of determining whether a sensitive instrument will have difficulty determining accurate measurements of physiological parameters of a patient, the method comprising:

selecting an interference detection mode on a patient monitor, said patient monitor configured to receive from a sensor one or more sensor signals responsive to light attenuated by tissue of a monitored patient and process the sensor signals to determine measurement values for one or more physiological parameters of said monitored patient, the sensor including a light source and one or more detectors housed in a sensor housing that positions the light source and said detector proximate said tissue;

electronically determining with said signal processor an amount of ambient electronic interference proximate said sensor; and

electronically outputting at least one of an audio or visual indication perceptible by a caregiver of said amount of said interference.

17. The method of claim 16, wherein said outputting comprises displaying a visual cue.

18. The method of claim 17, wherein said displaying said visual cue comprises changing a displayed measurement on at least one of a meter, a moving electronic dial, a bar graph, a series of LEDs, and an alphanumeric representation.

19. The method of claim 16, wherein said outputting comprises producing an audio cue.

20. The method of claim 19, wherein producing said audio cue comprises changing at least one of pitch or volume along an audio continuum.