以非侵入式連續血壓量測系統即時評估血管特性之動態變化

Evaluate the dynamic change of blood vessel characteristic using non-invasive continuous blood pressure measurement

饒憲堂(Hsien-Taung Jao)

指導教授 ： 徐良育

中原大學/工學院/醫學工程研究所/碩士(2007年)

https://doi.org/10.6840/CYCU.2007.00652

摘要

在臨床應用上，侵入性血壓量測裝置可紀錄連續血壓訊號，雖精準卻不能在一般例行性檢查中進行。非侵入式血壓量測計可應用於一般檢查或居家環境中，卻僅能提供收縮壓與舒張壓兩個特徵值，無法呈現完整血壓訊號的資訊。
本研究改良連續血壓系統，進行系統周邊裝置改良以及功能建構，主要包括血壓校正量測系統、周邊裝置及恆定壓力控制迴路。本系統內部以數位訊號處理單晶片進行即時特徵參數偵測與數位訊號處理，配合微處理器MSP430，搭配PI(比例-積分)控制法進行電動幫浦電壓調控，將氣囊內壓力維持於39~41mmHg之間，達到長時間、即時擷取連續血壓訊號之目的。
本研究針對六位正常年輕自願受測者，進行憋氣實驗以提升血壓與心率，同時利用所發展之非侵入式連續血壓波型量測裝置測量正常受測者手腕與手臂之連續血壓波型，並計算其血壓波型增大指數(augmentation index, AIx)、周邊阻抗(peripheral resistance)、動脈血管順應性(arterial compliance)等參數並以評估本裝置之正確性。實驗結果分為憋氣前、憋氣中與敝氣後，利用本系統即時處理之結果與Matlab處理結果進行比對。
系統測試結果，針對六位受測者，測試系統校正功能與床邊監視器(Spacelab 9036)所偵測之平均血壓、收縮壓與舒張壓間的相關度分別為0.71、0.78、0.90。連續血壓量測功能，針對六位受測者，本裝置扣除電動幫浦充氣訊號區段與訊號飽和區段後，平均資料可用率為47.3％，平均資料正確率為78.5％。
本研究完成之非侵入連續血壓量測系統，以數位訊號處理單晶片進行即時連續血壓量測功能與AIx、時間常數等特徵參數之偵測。系統利用PI控制法改善電動幫浦達到穩態響應時間，並增加血壓校正模式在。在硬體架構上，需改進裝置產生飽和的情況，在軟體撰寫上，修改電動幫浦充氣訊號區段的訊號處理方式，即可提升系統資料可用率。另一方面AIx、時間常數與振幅的偵測法，若能做部分修正，即可提升資料正確率與裝置整體性能。

關鍵字

動脈血管順應性 ； 周邊阻抗 ； 增大指數

並列摘要

In clinical application, invasive blood measurement can provide continuous blood pressure signal. Although it is accurate, but it can’t apply to routine inspection. In ordinary circumstances, noninvasive blood device must be used. But it can only provide diastolic and systolic blood pressure readings without detail blood pressure information.
In this study, improvements were made on the existing continuous blood pressure measurement system including blood pressure calibration, peripheral devices and constant pressure control. The proposed system uses DSP chip to process signal in real-time fashion. Additionally, the micro-controller (MSP430F149) implement proportional-integral (PI) control mechanism to control pump voltage in order to maintain the pressure inside the cuff around 39~41mmHg. Thus, long-term acquisition of continuous blood pressure signal is possible.
In this study, six normal volunteer were recruited to perform breath holding maneuver in order to increase heart rate and blood pressure. At the same time, parameters such as augmentation index (AIx), peripheral resistance and arterial compliance were computed from recorded continuous blood pressure signal to evaluate the device accuracy. During result analysis, comparisons were made between the real-time results from the proposed system and results from Matlab at time periods before breath holding, during breath holding and after breath holding.
The correlation between Spacelab (model 9036) and the proposed system are 0.71, 0.78 and 0.90 for mean, systolic and diastolic pressure, respectively. For continuous blood pressure monitoring capability, the data usability is 47.3％ and the data accuracy is 78.5％ after deducting saturation signal and pump active signal from the signals of six subjects.
In this study a non-invasive continuous blood pressure measurement system is completed. DSP chip is used to achieve real-time continuous blood pressure measurement and computation of parameters such as AIx and time constant. The proposed system uses PI control algorithm to improvement rising time and eliminate steady state error. For hardware improvement, the signal saturation need to be eliminated. For software improvement, the signal processing algorithm, during pump activation, also need to be improved. After improvement, the data usability will be improved. On the other hand, the detection algorithm for AIx, time constant and amplitude also need to be improved in order to increase data accuracy and system performance.

並列關鍵字

arterial compliance ； peripheral resistance ； augmentation index (AIx)

參考文獻

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