血壓可以作為判斷心血管狀況與生命穩定度的指標；在臨床上通常使用連續的侵入式血壓監測得到準確的血壓值，但是這容易造成血栓與感染的危險，而一般居家血壓計則無法測得連續的精準血壓值，故本研究希望結合兩種方式的優點，建構一套「連續非侵入式血壓量測系統」。
本實驗使用光體積變化信號(PPG)的非侵入感測方式，藉由市售儀器Nellcor OxiMax N-600x收取PPG訊號，再使用Matlab截取出PPG的特徵參數與OMRON MX-3收取的血壓值做回歸分析得到回歸方程式，並且透過此方程式進行血壓的推估，最後與實際血壓值進行相關性分析。
研究結果顯示所取的PPG特徵參數較能代表血管作用效應下的結果，所以與舒張壓(DBP)，平均血壓(MBP)具有高相關性，故系統以平均血壓作為預測的指標。並且經由實驗發現藉著將0度，90度，180度的實驗結果結合進行分析，能得到更佳的預測血壓值，因此，利用PPG的特徵參數發展連續非侵入式的血壓量測系統，此一方式具有相當高的可行性。

Blood pressure (BP) can be used as an index to determine cardiovascular health and stability of life. However, measuring BP accurately often necessitates the use of invasive clinical procedures that may lead to vascular thrombosis and infection. Although commercial sphygmomanometers do not bear risks of vascular thrombosis and infection, they cannot be used to measure BP continuously. Thus, to exploit the advantages of both invasive and non-invasive methods, we developed a continuous non-invasive BP assessment system.
To construct an algorithm for estimating BP, regression analyses of characteristic parameters in photoplethysmography (PPG) using the Nellcor OxiMax N-600x instrument and BP measured using the OMRON MX-3 instrument were used; PPG parameters were then substituted into this algorithm. In addition, the estimated BP was correlated with the accurately measured BP.
The results indicate that PPG parameters are closely related to vascular effects and are highly correlated with diastolic BP (DBP) and mean BP (MBP). Therefore, MBP was used as an index in the system. However, MBP was more accurately estimated using combinations of measurements made at shoulder flexion angles of 0ﾟ, 90ﾟ, and 180ﾟ. Thus, we conclude that the current continuous non-invasive BP assessment system using PPG parameters is clinically feasible.

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