Method and apparatus for continuous vitals monitoring
A health monitoring device for detecting a physiological attribute having a physiological attribute sensor including a first fiber Bragg grating (FBG) with a refractive index is configured to be placed in contact with a person's skin approximate to an artery or vein. A baseline sensor that includes a second fiber Bragg grating (FBG) also having a refractive index is configured to be placed in contact with a person's skin away from an artery or vein to provide a baseline refractive index. The device pulses light waves through the FBGs to provide a processor with reading of the refractive index from the FBGs. Based on the effective shifts of the Bragg wavelength due to axial strain on the FBGs, a physiological attribute estimator estimates a physiological attribute based on a calibration curve comparing a physiological attribute against strain.
1 . A health monitoring device, comprising:
a blood pressure sensor including a first fiber Bragg grating (FBG) configured to be placed in contact with a person's skin approximate to an artery or vein and having a first Bragg wavelength;
a baseline sensor including a second fiber Bragg grating (FBG) configured to be placed in contact with a person's skin away from the artery or vein and having a second Bragg wavelength and providing a measure of a baseline signal;
a light emitter configured to pulse light waves through the FBGs;
light sensors configured to receive pulsed light waves;
a processor including:
a data acquisition module configured to receive from the light sensor peak wavelengths reflected by the FBGs;
a comparator configured to determine effective shifts of the first Bragg wavelength and effective shifts of the second Bragg wavelength over time; and
a blood pressure estimator configured to estimate systolic and diastolic blood pressure based on 1) the effective shifts of the first Bragg wavelength corrected for drifts in the baseline signal based on the effective shifts of the second Bragg wavelength, and 2) an output of a physiological attribute monitor; and
a display for providing the estimated systolic and diastolic blood pressure.
2 . The device of claim 1 , wherein the blood pressure estimator is configured to estimate the systolic and diastolic blood pressure based on pulse transit times (PTT) between blood pressure pulses from the blood pressure sensor and the output, the output being one of an electrocardiogram (ECG) and a heart rate monitor.
3 . The device of claim 1 , wherein the processor is further configured to determine a pulse pressure waveform based on the effective shifts of the first Bragg wavelength corrected for drifts in the baseline signal based on the effective shifts of the second Bragg wavelengths.
4 . The device of claim 3 , wherein the processor is further configured to analyze pulse pressure waveform features including at least one of a stroke volume and a dicrotic notch.
5 . The device of claim 3 , further comprising a processor configured to analyze the pulse pressure waveform to determine a cardiovascular parameter including at least one of stroke volume and cardiac output.
6 . The device of claim 3 , further comprising a processor configured to perform a pattern recognition analysis of the pulse pressure waveform to estimate a likelihood of a disease exhibited by the person.
7 . The device of claim 1 , implemented in a wearable band at the person's arm or wrist, the first and second FBGs being embedded within a strap of the wearable band.
8 . The device of claim 7 , wherein the physiological attribute monitor is enclosed within the device the physiological attribute monitor including at least one of an ECG, a heartrate monitor, an oxygen saturation (SPO2) monitor, a blood glucose monitor, and a skin temperature monitor.
9 . The device of claim 1 , wherein the blood pressure estimator is configured to estimate the systolic and diastolic blood pressure based on a calibration function is derived from a timing correlation between the blood pressure sensor and an output of the physiological attribute monitor, the output being at least one of an ECG, heart rate, blood oxygen saturation.
10 . The device of claim 1 , wherein the processor further includes a heart rate monitor configured to detect periodic changes in surface deformation associated with a heartbeat.
11 . The device of claim 1 , wherein the physiological attribute monitor measures one of an ECG, blood oxygen saturation, body temperature, and blood glucose.
12 . The device of claim 1 , wherein the display is located on a remote device, and further including a transmitter configured to transmit estimated systolic and diastolic blood pressure to the display.
13 . The device of claim 1 , wherein the blood pressure sensor further includes a plurality of FBGs configured to be placed in contact with a person's skin close approximate to an artery or vein and having Bragg wavelengths, wherein each FBG is displaced from one another by a predetermined amount, and wherein the processor is configured to reconcile acquired data from the plurality of FBGs to optimize a measurement in effective shifts in Bragg wavelength of the blood pressure sensor.
14 . A method of monitoring health, comprising:
pulsing light waves through a first and second fiber Bragg gratings (FBGs) at 1) a blood pressure sensor including a first fiber Bragg grating (FBG) configured to be placed in contact with a person's skin approximate to an artery or vein and having a first Bragg wavelength, and 2) a baseline sensor including a second fiber Bragg grating (FBG) configured to be placed in contact with a person's skin away from the artery or vein and having a second Bragg wavelength and providing a measure of a baseline signal;
obtaining, from a light sensor configured to receive pulsed light waves, peak wavelengths reflected by the first and second FBGs;
determining effective shifts of the first Bragg wavelength and effective shifts of the second Bragg wavelength over time;
estimating systolic and diastolic blood pressure based on 1) the effective shifts of the first Bragg wavelength corrected for drifts in the baseline signal based on the effective shifts of the second Bragg wavelength, and 2) an output of a physiological attribute monitor; and
displaying the estimated systolic and diastolic blood pressure.
15 . The method of claim 14 , wherein estimating the systolic and diastolic blood pressure is based on pulse transit times (PTT) between blood pressure pulses from the blood pressure sensor and the output, the output being one of an electrocardiogram (ECG) and a heart rate monitor.
16 . The method of claim 14 , further comprising determining a pulse pressure waveform based on the effective shifts of the first Bragg wavelength corrected for drifts in the baseline signal based on the effective shifts of the second Bragg wavelengths.
17 . The method of claim 16 , further comprising analyzing pulse pressure waveform features including at least one of a stroke volume and a dicrotic notch.
18 . The method of claim 16 , further comprising analyzing the pulse pressure waveform to determine a cardiovascular parameter including at least one of stroke volume and cardiac output.
19 . The method of claim 16 , further comprising performing a pattern recognition analysis of the pulse pressure waveform to estimate a likelihood of a disease exhibited by the person.
20 . The method of claim 16 , wherein estimating the systolic and diastolic blood pressure is based on a calibration function derived from a timing correlation between the blood pressure sensor and an output of the physiological attribute monitor, the output being at least one of an ECG, heart rate, blood oxygen saturation.