Peripheral Hemodynamics Estimation Using the Photoplethysmography Method

Figures

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  Figure 1. (a) Finger-mounted measurement tool; (b) mounted state; (c) cross-sectional view of the finger-mounted measurement tool.

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  Figure 2. Measurement posture with the measurement device held at navel, chest, and forehead heights.

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  Figure 3. Photoplethysmogram height (S) and acceleration plethysmogram a-wave peak height (a).

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  Figure 4. Velocity and acceleration plethysmogram feature values: (a) inverse full width at half-maximum velocity plethysmogram (FWHMVPG); (b) ab time; (c) normalized a-b, normalized a-d.

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  Figure 5. Penetration depth of green light (green arrow) and near-infrared light (red arrow) received by the photodiode (PD).

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  Figure 6. Example of changes in the a-wave peak time difference between green light and near-infrared acceleration plethysmograms (time delay between green light and near-infrared light a-wave peaks) for the same subject when the time delay (blue arrow) is (a) large and (b) small.

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  Figure 7. Relationship between time delay of green light a-wave peak from near-infrared light a-wave peak and reciprocal of green light photoplethysmogram amplitude (S).

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  Figure 8. Relationship between systolic blood pressure and each feature value when the height of the measurement site (finger) from the heart changes and when the vicinity of the measurement site is cooled: (a) 1/FWHMVPG (green light); (b) a/S (green light); (c) (a-b)/(a-d) (green light); (d) 1/ab time (green light).

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  Figure 9. Relationship between systolic blood pressure and each feature value when the height of the measurement site (finger) from the heart changes and when the vicinity of the measurement site is cooled: (a) 1/FWHMVPG (near-infrared light); (b) a/S (near-infrared light); (c) (a-b)/(a-d) (near-infrared light); (d) 1/ab time (near-infrared light).

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  Figure 10. Examples of waveforms with different photoplethysmogram rising slopes: (a) photoplethysmogram waveform; (b) 1/FWHMVPG and a/S change; (c) (a-b)/(a-d) and 1/ab time change.

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  Figure 11. Relationship between wrist systolic blood pressure and 1/FWHMVPG (green light).

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  Figure 12. Relationship between the wrist systolic blood pressure and the time delay of the green light a-wave peak from the near-infrared light a-wave peak.