Development of a Continuous Blood Pressure Assessment System by Pulse Transit Techniques

  • 柯 佳伶

Student thesis: Master's Thesis

Abstract

Blood pressure (BP) is one of the vital signs and is an index that helps determining the stability of life In this respect some spinal cord injury patients need to take the tilt table test When doing so the posture changes abruptly and may cause a patient’s BP to change abnormally This may cause patients to feel discomfort and even feel as though their life is threatened Therefore if a continuous non-invasive BP assessment system were built it could help to alert health care professionals in the process of rehabilitation when the BP value is out of range According to research the relationship between pulse transit time and BP is a negative relationship Hence in our research BP assessed by the pulse transit technique was developed In the system we use a self-made photoplethysmograph (PPG) sensor and filter circuit to detect two PPG signals LabVIEW was used to display the waveform and control the voltage level as well as magnify and calculate the time difference; then a DAQ card produced by National Instruments was used to obtain the analog signal Finally the BP can immediately be assessed by the trend line According to the results of this study the relationship between the systolic BP and pulse transit time has a highly negative linear correlation (R2=0 8) Further we used the trend line to assess the value of the BP and compared it to a commercial sphygmomanometer (Omron MX3); the error rate of the system was found to be in the range of ±10% which is within the permissible error range of a commercial sphygmomanometer Thus to continuously monitor BP by the pulse transit technique is verified as having good feasibility
Date of Award2014 Aug 24
Original languageEnglish
SupervisorTainsong Chen (Supervisor)

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