Distinguished Professor Paul Chao at National Chiao Tung University (NCTU), have developed successfully the world-first hand-held blood flow volume (BFV) sensor. The sensor is designed employs special wavelength lighting to sense the volume pulsation of wrist artery under the skin based on the principle of Photoplethysmography (PPG), leading further to heart rate (HR), blood flow volume (BFV), blood pressure (BP) and atrial fibrillation (AFib).

The size of the sensor is in half of a popular smart phone, therefore, easy to operate, no radiation and non-invasiveness. The obtained BFV can predict dehydration, heat stroke, mountain sickness and of course he AVF quality of hemodialysis patients. The collected PPG data and obtained BFV are transmitted to cloud to be monitored by doctors and hospital for early diagnosis.

Since the first-generation of this BFV was reported in 2017, continuous effort has been dedicated to improve its performance. The optical mask has been re-designed to overcome user’s mis-positioning and ambient lighting interference. Also, the doctors at two medical centers have participated in collecting more than hundreds of sets of data at hospital sites. With an AI model successfully established based these data, the BFV can be predicted with calibration in a favorable accuracy for future FDA approval, elevating significantly the associated usability.

In Taiwan, there is a significant portion in population suffers chronic kidney dis-ease (CKD), many of whom are at the end-stage renal disease (ESRD), replying on the treatment of hemodialysis (HD) to sustain the fundamental functions of kidney. An estimated 900M TWD each year, based on 2017 Taiwan Society of Kidney, is spent on the HD by the national healthcare. To enable HD, the vascular accesses on patients are surgically orchestrated with an anastomosis of artery and vein, referred to as AVF.

With long-time operation of hemodialysis, AVF could malfunction due to vascular thrombosis or stenosis occurring near AVF region. Therefore, how to monitor and control the quality of vascular access at AVF region over an extensive period of time becomes a critical issue for patients undergoing hemodialysis. Available technologies for monitoring AVF are angiography and Doppler ultrasound.

Angiography is invasive, while Doppler ultrasound, though non-invasive, requires a large-sized module to accommodate its components, not to mention its high cost and the need of experienced operators. The PPG-type BFV sensor developed by Prof. Chao serves well as a small-sized, hand-held and low-cost device for patients to measure at home with high precision. Compared to the standard monitors, the developed BFV sensor can achieve an accuracy of 91%, and capable of effective early diagnosis to minimize the necessity of re-operations on AVFs

Since 2014, significant effort has been dedicated by Prof. Chao’s Lab on this PPG sensor. There has been drawn interests from 24 companies, 36 collaboration projects, technology transfers and consulting. The developed technologies also earned many awards, like the 13th, 15th and 16th National Innovation Award, and most, recently, the 2019 IEEE Sensors Council Technical Achievement Award in the field of Sensor Systems or Networks - Advanced Career.

Many smart wearable devices were in the market with considerable profits in the past ten years. It is estimated that in 2025 the global market of the smart health devices in 2025 will amount to 24.46 billion USD. Among all the smart health devices, quite a few of them aims to monitor cardiovascular functionalities of users. The world health organization reported that there are about 1.7 million died each year due to heart diseases, which is 31% of death toll in the world.

The PPG sensor for BFV measurement is planned to pass FDA approval at the end of the next year, benefits greatly HD patients. On the other hand, the PPG sensor can also equipped with functions of detecting heart rate (HR), blood pressure (BP) and atrial fibrillation (AFib).

In the next phase of PPG sensor development, Prof. Chao has successfully designed and realized a world–first flexible PPG sensor patch and its algorithms to estimate heart rate (HR),etc. the long-time wearability facilitates continuous monitoring on the cardiovascular functionalities of users. The collected data will be the important bases towards smart, in-depth prognosis, precision medicine for cardiovascular patients.