User-worn device for noninvasively measuring a physiological parameter of a user
The present disclosure relates to noninvasive methods, devices, and systems for measuring various blood constituents or analytes, such as glucose. In an embodiment, a light source comprises LEDs and super-luminescent LEDs. The light source emits light at at least wavelengths of about 1610 nm, about 1640 nm, and about 1665 nm. In an embodiment, the detector comprises a plurality of photodetectors arranged in a special geometry comprising one of a substantially linear substantially equal spaced geometry, a substantially linear substantially non-equal spaced geometry, and a substantially grid geometry.
1. A user-worn device configured to non-invasively measure a physiological parameter of a user, the user-worn device comprising:
one or more light emitting diodes (LEDs) configured to emit a spectrum of light;
one or more photodiodes configured to receive a spectrum of light after attenuation by tissue of the user and output one or more signals responsive to the received spectrum of light;
a thermistor configured to output a temperature signal; and
one or more processors configured to:
receive the temperature signal;
calculate a temperature of the user based on the temperature signal;
receive the one or more signals from at least one of the photodiodes;
calculate, responsive to the one or more signals and the temperature signal, a measurement of the physiological parameter of the user, wherein the temperature signal is used to compensate for temperature-dependent effects on the received spectrum of light caused by water absorption resulting in an alteration of the received spectrum of light; and
trigger a notification of an unsafe temperature based on at least the calculated temperature of the user.
2. The user-worn device of claim 1 further comprising:
a user interface comprising a touch-screen display, wherein the user interface is configurable to display at least:
indicia responsive to the measurement of the physiological parameter,
the calculated temperature of the user, and
the notification of the unsafe temperature; and
a strap configured to position the user-worn device on the user.
3. The user-worn device of claim 1 further comprising:
a user interface comprising a touch-screen display, wherein the user interface is configurable to display at least:
indicia responsive to the measurement of the physiological parameter, and
the notification of the unsafe temperature, wherein the notification comprises an alarm; and
a strap configured to position the user-worn device on the user.
4. The user-worn device of claim 3 , wherein the unsafe temperature indicates that the user is too hot.
5. The user-worn device of claim 3 , wherein the unsafe temperature indicates that the user is too cold.
6. The user-worn device of claim 1 , wherein the physiological parameter comprises at least one of: methemoglobin, carboxyhemoglobin, or carbon monoxide.
7. The user-worn device of claim 1 , wherein the physiological parameter comprises oxygen or oxygen saturation.
8. The user-worn device of claim 1 , wherein the physiological parameter comprises trending information.
9. The user-worn device of claim 1 , wherein the physiological parameter comprises glucose.
10. The user-worn device of claim 1 , wherein the one or more LEDs and the one or more photodiodes are arranged on a same side of the tissue of the user.
11. The user-worn device of claim 1 further comprising:
a front-end interface comprising one or more amplifiers and one or more analog to digital converters (ADCs), wherein the front-end interface receives the signals from the photodiodes, the one or more amplifiers amplify the signals, and the one or more ADCs convert the signals to digital information, and wherein the one or more processors receive the converted signals.
12. A physiological measurement system comprising:
a user worn device according to claim 1 ; and
a mobile phone configured to wirelessly communicate with the user-worn device.
13. The user-worn device of claim 1 , wherein the temperature signal is used to compensate for wavelength drift.
14. The user-worn device of claim 1 , wherein the one or more processors are further configured to:
detect, based on the temperature signal, an extreme temperature in tissue of the user.
15. The user-worn device of claim 14 , wherein the extreme temperature is a temperature that is too cold.
16. The user-worn device of claim 14 , wherein the extreme temperature is a temperature that is too hot.
17. The user-worn device of claim 1 , wherein the physiological parameter comprises total hemoglobin.
18. A user-worn device configured to non-invasively measure a physiological parameter of a user, the user-worn device comprising:
one or more light emitting diodes (LEDs) configured to emit a spectrum of light;
one or more photodiodes configured to receive a spectrum of light after attenuation by tissue of the user and output one or more signals responsive to the received spectrum of light;
a thermistor configured to output a temperature signal; and
one or more processors configured to:
receive the temperature signal;
determine, based at least in part on the temperature signal, a temperature of tissue of the user;
receive the one or more signals from at least one of the photodiodes; and
calculate, responsive to the one or more signals and the temperature signal, a measurement of the physiological parameter of the user, wherein the temperature signal is used to compensate for temperature-dependent effects on the received spectrum of light caused by water absorption resulting in an alteration of the received spectrum of light.
19. The user-worn device of claim 18 , wherein the one or more processors are further configured to:
detect, based at least in part on the temperature of tissue of the user, low perfusion in tissue of the user.
20. The user-worn device of claim 19 , wherein detecting low perfusion comprises:
determining a drop in temperature in tissue of the user.
21. The user-worn device of claim 19 , wherein detecting low perfusion comprises:
determining that tissue of the user is too cold.
22. A physiological measurement system comprising:
a user worn device according to claim 18 ; and
a mobile phone configured to wirelessly communicate with the user-worn device.
23. The user-worn device of claim 18 , wherein the temperature signal is used to compensate for wavelength drift.
24. The user-worn device of claim 18 , wherein the physiological parameter comprises total hemoglobin.
25. The user-worn device of claim 18 , wherein the physiological parameter comprises glucose.
26. The user-worn device of claim 18 further comprising:
a thermistor configured to output a second temperature signal responsive to a temperature of the one or more LEDs.
27. The user-worn device of claim 26 , wherein the one or more processors are further configured to:
compensate for power drift of the one or more LEDs using the second temperature signal.
28. The user-worn device of claim 27 , wherein the power drift is based on heating.
29. The user-worn device of claim 26 , wherein the one or more processors are further configured to:
compensate for a change of wavelength centroid of the one or more LEDs using the second temperature signal.
30. The user-worn device of claim 29 , wherein the change of wavelength centroid is based on heating.