Blood Pressure and Heart Rate Measurements Using Fiber Bragg Grating Sensor with Optical Power Detection Scheme

Figures

• 

  Figure 1. Optical power detection scheme to acquire vascular pulsation waveform with two identical FBGs used. BBLS: broadband light source; OI: optical isolator; FC: 3 dB fiber coupler; FBG1 and FBG2: fiber Bragg gratings; PD: photodetector. The symbol X denotes no Fresnel reflection from fiber end faces.

• 

  Figure 2. Reflection spectrum of FBG1 and the transmission spectrum of FBG2 (a) when FBG1 does not bear any vascular pulsating stress, and (b) when FBG1 bears some vascular pulsating stress.

• 

  Figure 3. (a) Schematic diagram showing a protective structure for protecting an FBG sensor and its adjacent bare fiber. (b) The silicone sheet with an FBG, its adjacent bare fiber, and a part of loose-tube fiber embedded inside.

• 

  Figure 4. Schematic diagram showing a silicone sheet containing an FBG sensor is pressed by a U-shaped box with a clamp to closely contact the skin of wrist.

• 

  Figure 5. An arm of a subject is fixed by a clamp in acquiring vascular pulsation waveform.

• 

  Figure 6. Vascular pulsation waveform of a subject acquired for a time period of 25 sec before signal treatment (a) and after signal treatment (b).

• 

  Figure 7. A pulse waveform detected by the PD. U point is the onset point for blood ejection from left ventricle when the heart contracts, P is the peak of the percussion wave during systole, T represents the tidal wave, V is the valley of the pulse representing the beginning of diastole (i.e., the descending wave trough point), D is the peak of the dicrotic wave, and point E represents the end of diastole.

• 

  Figure 8. Correlation plots of calculated BP values against reference BP values for 29 subjects. (a) is for SBP and (b) for DBP.

• 

  Figure 9. Error distributions of calculated BP values and reference BP values for the 29 subjects. (a) is for SBP and (b) for DBP.

• 

  Figure 10. Correlation plots of calculated BP values against reference BP values for 29 subjects. (a) is for SBP and (b) for DBP.

• 

  Figure 11. Error distributions of calculated BP values and reference BP values for the 29 subjects. (a) is for SBP and (b) for DBP.

• 

  Figure 12. Correlation plots of calculated BP values against reference BP values for 29 subjects. (a) is for SBP and (b) for DBP.