建構可攜式低功耗藍牙生理訊號量測裝置：以量測血壓為例

Development of a portable Bluetooth Low Energy device for biosignal acquisition : using blood pressure measurement as example

翁旌賀(Jine-He Weng)

指導教授 ： 徐良育

中原大學/工學院/醫學工程研究所/碩士(2014年)

https://doi.org/10.6840/cycu201400769

摘要

近年來穿戴式量測裝置的需求日益劇增，有許多量測裝置都漸漸朝向輕便及簡易的方向來設計，讓其便於穿戴且不影響日常生活。本研究目標為發展一套適用於穿戴式的生理訊號擷取系統，並利用此系統來擷取非侵入式血壓訊號。
歷年國人十大死因中，心血管疾病都榜上有名，其中又以高血壓最具風險性，高血壓在發作期間並沒有明顯的症狀，非常容易被忽略，而導致更嚴重的併發症發生，因此定期監測血壓十分重要。目前市面上最普遍的非侵入式電子血壓計，較適用於例行性的血壓檢查，但其體積過大不便於攜帶，且必須使用壓脈帶進行量測，也因此容易讓使用者在量測過程中有不舒適感。
本研究結合了本實驗室無氣囊血壓擷取裝置的概念，建構一小型血壓感測器，並利用低功耗藍牙及iOS行動裝置，將血壓訊號經由CC2541以無線的方式傳輸到行動裝置上做進一步的分析及儲存，達到低功耗及提升可攜性之目的。
研究中所設計的低功耗生理訊號擷取模組尺寸為33mm×25mm×8mm(長×寬×高)。經實際測試能夠確實採集生理訊號，在傳輸過程中也沒有封包遺漏的狀況，並在使用CR2032及採樣頻率250Hz的情況下可連續量測長達19個小時以上，在每天量測3次及每次量測30秒的情況下可至少可使用760天。其傳輸效能及省電能力都相當優異。實際量測結果中，本研究測試了10位志願者，與市售之血壓計做比較，發現本裝置所測得的收縮壓、舒張壓及平均血壓與市售血壓計的相關度分別為0.06、0.22及0.14，結果並不理想，原因可能為裝置使用的不熟悉。
最後本研究完成了以低功耗藍牙為基礎的生理訊號量測裝置，並利用iOS行動裝置運算、儲存及顯示，提高了量測及攜帶的便利性，另外在功耗的部分也有非常明顯的改善。除了血壓的應用外，往後還可以使用在其他生理訊號的擷取，提升裝置的效能以及續航力，因此非常適用於穿戴式裝置。

關鍵字

血壓 ； 無氣囊 ； 低功耗藍牙 ； 生理訊號 ； iOS行動裝置

並列摘要

In recent years, the demand of the wearable measurement devices increases gradually. Many measurement devices are designed to be lightweight and easy to use, to make them wearable and don’t affect the daily life. The purpose of this study is to develop a biosignal acquisition system that is suitable for wearable devices, and use it to acquire non-invasive blood pressure signal.
Cardiovascular diseases are one of the leading causes of death in Taiwan, among which the hypertension is the most risky cause. There have no obvious symptoms during the onset of hypertension. It is very easy to be ignored, and lead to more serious complications. Therefore, regular blood pressure measurement is very important. Currently, the most common non-invasive electronic sphygmomanometer is suitable for routine blood pressure monitor. However, it is too large to carry around and it must use cuff during blood pressure measurement which make users uncomfortable.
This study combines the concept of cuff-less blood pressure measurement technique that was developed in our laboratory with Bluetooth Low Energy and iOS device to achieve low power consumption and to enhance portability. A small blood pressure sensor was construct and the acquired blood pressure signal was transmit through CC2541 to the iOS device for analysis and storage.
The dimension of the low power biosignal acquisition system constructed in this study is 33mm×25mm×8mm(L×W×H). After the actual test, the system can acquire biosignal faithfully, and have no packet loss during transmitting. When using a CR2032 battery to power the system and working on 250Hz sampling rate it can measure continuously for up to 19 hours. For typical usage, three measurements in a day and every measurement last for 30s, this system can last for up to 760 days. The transmission performance and power saving capabilities are excellent.
For non-invasive blood pressure measurement evaluation, this study recruits ten health volunteers to verify the system and to compare the measurement results with a commercial sphygmomanometer. The Pearson’s coefficients between the novel system and commercial sphygmomanometer are 0.06, 0.22 and 0.14 for SBP, DBP and MAP, respectively. The results are not satisfying and the reasons may be due to subjects are unfamiliar with the device.
In conclusion, this study accomplishes a biosignal acquisition device base on Bluetooth Low Power. The system uses iOS device to calculate, storage and display acquired signal. It not only improves the convenience of measuring and ease of carrying but also reduces the power consumption. In addition to non-invasive blood pressure application, it can also be easily adapted to capture other biosignal, with improved performance and extending the battery life. Thus it is very suitable for used in wearable devices.

並列關鍵字

Blood Pressure ； iOS portable Device ； Bluetooth Low Energy ； Vital Signs ； Cuff-less

參考文獻

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[17] 胡義騰, "以智慧型手機為核心之新型無氣囊血壓量測," 中原大學碩士論文, 中華民國 102 年 7 月.

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