| Summary: | 碩士 === 國立東華大學 === 電機工程學系 === 103 === In recent years, baroreflex sensitivity (BRS) has been applied to assess autonomic nervous systems activity in many clinical trials. This indicator has been proposed to relate to many cardiovascular diseases, such as hypertension, myocartial infarction, stroke, etc. Traditionally, BRS is defined as the relationship between the changes of blood pressure and heart beat interval (indicated by ECG R-R interval) after intravenous injection of vasoactive agents such as phenylepirin or sodium nitroprusside and so on.
There are some commercialized instruments used to assess BRS by a noninvasive method to measure blood pressure, but these instruments are high cost and need professionals to operate. Therefore, this thesis attempted to use digital volume pulse acquired by infrared sensor photoplethysmography (PPG) to replace invasive blood pressure assessment. We used compare spontaneous sequence to calculate BRSs by using PPG signals and blood pressure. Reproducibility of these to indicators are good and validity are also good as compared with the traditional BRS method.
Furthermore, we used ternary arithmetic coding to quantify the oscillation of blood pressure and heart rates. The similarity between these two signals was proposed to be used as a new indicator of baroreflex activity, named ternary arithmetic coding probability (TACpr).
This thesis using XCTION VIEW and photoplethysmography system to acquire BP , ECG and PPG data in 11 Wistar Kyoto (WKY) rats to analyze BRSspt and TACpr, and then verify the reproducibility. Validity of these parameters was identified as compared with traditional method by intravenous injection of phenylephrin namly BRSpheny.
Our results showed that BRSspt and TACpr had very good reproducibility. The validity of these two parameterswas also good and acceptable. Meanwhile, we also found that pulse-pulse interval (PPI) could substitute for ECG R-R interval (RRI) to be used in assessing BRS in either method. Lastly, we demonstrated that TACpr was significantly attenuated as BRSspt was in Streptozocin-induced diabetic rats.
In summary, DVP acquired by PPG could replace BP in BRS assessment, and TACpr might be a better method than the traditional one for assessing BRS in clinical studies.
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