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. 2024 Oct 1:12:675-683.
doi: 10.1109/JTEHM.2024.3471468. eCollection 2024.

A Novel Chest-Based PPG Measurement System

Qiuyang Lin  1 , Haocun Wang  2 , Dwaipayan Biswas  1 , Zheyi Li  1   3 , Erika Lutin  1   3 , Chris van Hoof  1   3 , Mingyi Chen  2 , Nick van Helleputte  1
Affiliations

A Novel Chest-Based PPG Measurement System

Qiuyang Lin et al. IEEE J Transl Eng Health Med. .

Abstract

Advancements in integrated circuit (IC) technology have accelerated the miniaturization of body-worn sensors and systems, enabling long-term health monitoring. Wearable electrocardiogram (ECG), finger photoplethysmogram (PPG), and wrist-worn PPG have shown great success and significantly improved life quality. Chest-based PPG has the potential to extract multiple vital signs but requires ultra-high dynamic range (DR) IC to read out the small PPG signal among large respiration and artifacts inherent in daily life. This paper presents a dedicated high DR system for wearable chest PPG applications with a small form factor. The whole measurement system is integrated on a 20 cm2 PCB board. We have formulated a comprehensive evaluation protocol to validate the system with on-body chest PPG measurement in the workspace environment. First, chest PPG data was obtained from 6 adults and compared to data from a standard ECG patch. This system showed an average absolute deviation (AD) of 0.41 beats per minute, achieving > 99.53% heart rate (HR) accuracy. Second, chest PPG was recorded and compared to conventional PPG finger clip and PPG wristband, also showing > 98.6% HR matching and an absolute deviation in the standard deviation of NN intervals (SDNN) of < 12.8 ms for HRV monitoring within the protocol. Moreover, it successfully derives other vital parameters such as respiration rate and blood oxygen level (SpO2), showing the advancement among all these three reference modalities. This system can pave the way for new application areas, such as chest patches, to monitor chronic heart and respiratory diseases.

Keywords: Chest photoplethysmogram (PPG); blood oxygen level (SpO₂); dynamic range (DR); electrocardiogram (ECG); respiration.

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Figures

FIGURE 1.
FIGURE 1.
(a) A wearable ECG patch and a standard ECG signal (b) A wearable PPG watch and a standard PPG signal.
FIGURE 2.
FIGURE 2.
Respiratory monitoring metrics using chest PPG.
FIGURE 3.
FIGURE 3.
The proposed wearable chest PPG monitoring system with the chest PPG monitoring ASIC block and flexible LED/PD. The system can communicate to PC/Smart Phone by USB. The ASIC is implemented with TSMC 180 nm and can readout PPG signal from the PD.
FIGURE 4.
FIGURE 4.
The chest PPG system prototype with a size of 5 cm formula image cm, the flexible probe.
FIGURE 5.
FIGURE 5.
(a) IMEC 3-channel ECG patch. (b) TI 4403 PPG evaluation module. (c) IMEC Chill+ wrist module.
FIGURE 6.
FIGURE 6.
A 7-minute experimental protocol comprising: normal breath, deep breath, hold breath, finger tap and swing arm phases.
FIGURE 7.
FIGURE 7.
Overview of the signal processing methodology adopted for the analysis.
FIGURE 8.
FIGURE 8.
Four chest PPG area, roughly classified by a rectanglar shape : (a) upper lateral area (b) lower lateral area (c) upper anterior area (d) lower anterior area, and the corresponding PPG waveforms.
FIGURE 9.
FIGURE 9.
(a) A sample chest PPG/ECG measurement results; (b)Band-pass filtered chest PPG/ECG signals in normal breathing period; (c)Low-pass filtered respiration rates.
FIGURE 10.
FIGURE 10.
(a) A sample chest/finger PPG measurement results; (b) Band-pass filtered chest/finger PPG in normal breathing period.
FIGURE 11.
FIGURE 11.
(a) Chest PPG and wrist PPG signals; (b) Band-pass filtered chest/wrist PPG in normal breathing period.
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References

    1. Mathers C. D., Boerma T., and Fat D. M., “Global and regional causes of death,” Brit. Med. Bull., vol. 92, no. 1, pp. 7–32, Dec. 2009. - PubMed
    1. Ross J. S., et al. , “Einthoven’s string galvanometer,” Geriatrics, vol. 53, no. 2, p. 89, 1998. - PubMed
    1. Baranchuk A., et al. , “Electromagnetic interference of communication devices on ECG machines,” Clin. Cardiol., vol. 32, no. 10, pp. 588–592, Oct. 2009. - PMC - PubMed
    1. Van Mieghem C., Sabbe M., and Knockaert D., “The clinical value of the ECG in noncardiac conditions,” Chest, vol. 125, no. 4, pp. 1561–1576, Apr. 2004. - PubMed
    1. Sarkar S., Bhattacharyya P., Mitra M., and Pal S., “Automatic detection of obstructive and restrictive lung disease from features extracted from ECG and ECG derived respiration signals,” Biomed. Signal Process. Control, vol. 71, Jan. 2022, Art. no. 102791.

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