A Novel Wireless Photoplethysmography Blood-Flow Volume Sensor for Assessing Arteriovenous Fistula of Hemodialysis Patients

Chiang, Pai Kai; Chao, Paul C.-P.; Tarng, Der‐Cherng; Yang, Chi‐Rei

doi:10.1109/tie.2017.2701780

Cited by 29 publications

(13 citation statements)

References 35 publications

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“…These sensors can monitor high-volume blood flow, such as in an arteriovenous fistula. 25,26 PPG sensors have not yet been shown to monitor lower volume blood flow, such as occurs in a flap pedicle.…”

Section: Discussionmentioning

confidence: 99%

A Novel Technology for Free Flap Monitoring: Pilot Study of a Wireless, Biodegradable Sensor

Oda

Beker

Kaizawa

et al. 2019

J Reconstr Microsurg

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Background Accurate monitoring of free flap perfusion after complex reconstruction is critical for early recognition of flap compromise. Surgeons use a variety of subjective and objective measures to evaluate flap perfusion postoperatively. However, these measures have some limitations. We have developed a wireless, biodegradable, and flexible sensor that can be applied to real-time postoperative free flap monitoring. Here we assess the biocompatibility and function of our novel sensor. Methods Seven Sprague–Dawley (SD) rats were used for biocompatibility studies. The sensor was implanted around the femoral artery near the inguinal ligament on one leg (implant side) and sham surgery was performed on the contralateral leg (control side). At 6 and 12 weeks, samples were harvested to assess the inflammation within and around the implant and artery. Two animals were used to assess sensor function. Sensor function was evaluated at implantation and 7 days after the implantation. Signal changes after venous occlusion were also assessed in an epigastric artery island flap model. Results In biocompatibility studies, the diameter of the arterial lumen and intima thickness in the implant group were not significantly different than the control group at the 12-week time point. The number of CD-68 positive cells that infiltrated into the soft tissue, surrounding the femoral artery, was also not significantly different between groups at the 12-week time point. For sensor function, accurate signaling could be recorded at implantation and 7 days later. A change in arterial signal was noted immediately after venous occlusion in a flap model. Conclusion The novel wireless, biodegradable sensor presented here is biocompatible and capable of detecting arterial blood flow and venous occlusion with high sensitivity. This promising new technology could combat the complications of wired sensors, while improving the survival rate of flaps with vessel compromise due to its responsive nature.

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Section: Discussionmentioning

confidence: 99%

A Novel Technology for Free Flap Monitoring: Pilot Study of a Wireless, Biodegradable Sensor

Oda

Beker

Kaizawa

et al. 2019

J Reconstr Microsurg

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“…Table 4 also shows that though the bilateral PPG sensors using neural networks [ 5 ] claimed the highest accuracy, the sensors’ sizes are too large to turn into a portable device. Moreover, the prior research of the authors [ 6 ] using a single PPG sensor with the neural network algorithms reveals an extremely high type II error, which may lead to delayed treatments in clinical practice. As for the researches presented in References [ 2 , 3 ], though acoustic sensors using stethoscope auscultation show promising results, the long tubes of the stethoscope sensors are inferior to a PPG sensor for device portability.…”

Section: Discussionmentioning

confidence: 99%

“…Next, to deal with the low frequency motion artifacts, such as vasomotion (0.8–0.25 Hz), respiration (0.2–0.4 Hz), etc., an FIR bandpass filter with cutoff frequencies 0.82 Hz and 10 Hz is designed to cancel the DC drifting, as shown in Figure 9 . Finally, for other non-periodic motion artifacts, such as patients’ talking, moving, etc., the PSD evaluation method is introduced herein to provide a quantitative index for describing the quality of PPG signals [ 6 ]. It can be seen from Figure 10 that PPG signals are contaminated by motion artifacts with much lower PSD values due to the large white noise induced by the non-periodic motion.…”

Section: System Designsmentioning

confidence: 99%

“…Du Y.-C. et al [ 5 ] presented a bilateral photoplethysmography (PPG) sensor system, assessing AVF using a neural network algorithm with very high accuracy of 94.82%, but with only eleven subjects. Chiang P. Y. et al [ 6 ] published their study on monitoring the BFV at AVF using a single PPG sensor, and the clinical results showed correlation of 0.7176. However, very serious overestimation occurred in Reference [ 6 ], which resulted in a very high (>50%) type II error.…”

Section: Introductionmentioning

confidence: 99%

“…Chiang P. Y. et al [ 6 ] published their study on monitoring the BFV at AVF using a single PPG sensor, and the clinical results showed correlation of 0.7176. However, very serious overestimation occurred in Reference [ 6 ], which resulted in a very high (>50%) type II error. To the best of the authors’ knowledge, there is still no portable, small-sized PPG sensor providing a reliable and inexpensive solution to AVF assessment.…”

Section: Introductionmentioning

confidence: 99%

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A Portable, Wireless Photoplethysomography Sensor for Assessing Health of Arteriovenous Fistula Using Class-Weighted Support Vector Machine

Chao

Chiang

Kao

et al. 2018

Sensors

Self Cite

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A portable, wireless photoplethysomography (PPG) sensor for assessing arteriovenous fistula (AVF) by using class-weighted support vector machines (SVM) was presented in this study. Nowadays, in hospital, AVF are assessed by ultrasound Doppler machines, which are bulky, expensive, complicated-to-operate, and time-consuming. In this study, new PPG sensors were proposed and developed successfully to provide portable and inexpensive solutions for AVF assessments. To develop the sensor, at first, by combining the dimensionless number analysis and the optical Beer Lambert’s law, five input features were derived for the SVM classifier. In the next step, to increase the signal-noise ratio (SNR) of PPG signals, the front-end readout circuitries were designed to fully use the dynamic range of analog-digital converter (ADC) by controlling the circuitries gain and the light intensity of light emitted diode (LED). Digital signal processing algorithms were proposed next to check and fix signal anomalies. Finally, the class-weighted SVM classifiers employed five different kernel functions to assess AVF quality. The assessment results were provided to doctors for diagonosis and detemining ensuing proper treatments. The experimental results showed that the proposed PPG sensors successfully achieved an accuracy of 89.11% in assessing health of AVF and with a type II error of only 9.59%.

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Functional Soft Composites As Thermal Protecting Substrates for Wearable Electronics

Shi

Wang

Yin

et al. 2019

Adv Funct Materials

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Thermal management of wearable electronics integrated with biological tissues remains one of the critical challenges for their practical applications. The undesired heating can cause thermal discomfort or even thermal damage to biological tissues. Here, a novel thermal protecting substrate design is proposed for wearable electronics with abilities to manipulate the heat flow and efficiently absorb the excessive heat energy without the compromise of substrate flexibility. The thermal protecting substrate features a functional soft composite, which incorporates the embedded phase change material with a thin metal film on the top in a soft polymer. Compared with conventional substrate, the proposed thermal protecting substrate can reduce the peak temperature increase by over 85% with appropriate parameters. Experimental and numerical studies reveal the fundamental aspects of the design and operation of functional soft composite to effectively avoid excessive heating of biological tissues. Influences of geometrical parameters on temperature reduction are investigated. Device demonstration of thermal protecting substrate in a wearable heater on pig skin illustrates the unusual capability to reduce the maximum skin temperature, thereby enabling practical applications of wearable electronics and creating engineering opportunities in biointegrated applications requiring thermal protection of biological tissues.

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A Novel Wireless Photoplethysmography Blood-Flow Volume Sensor for Assessing Arteriovenous Fistula of Hemodialysis Patients

Cited by 29 publications

References 35 publications

A Novel Technology for Free Flap Monitoring: Pilot Study of a Wireless, Biodegradable Sensor

A Novel Technology for Free Flap Monitoring: Pilot Study of a Wireless, Biodegradable Sensor

A Portable, Wireless Photoplethysomography Sensor for Assessing Health of Arteriovenous Fistula Using Class-Weighted Support Vector Machine

Functional Soft Composites As Thermal Protecting Substrates for Wearable Electronics

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