Oscillometric Waveform Evaluation for Blood Pressure Devices

Abstract

Most of the noninvasive blood pressure (NIBP) device algorithms have been derived from the clinical trials at various hospitals and human races in developed countries. It is urgent to develop an algorithm for NIBP devices for Indian citizens. In this regard, we have developed a flexible pressure sensor to record the human body's oscillometric waveform (OMW). As we know, assessing human blood pressure (BP) by noninvasive techniques is virtually a revolutionary step in biomedical science and engineering. High blood pressure is one of the most critical risk factors for heart disease and death; therefore, continuous monitoring of BP is necessary. We have obtained the BP pulse waveform by the flexible capacitive pressure sensor and further estimated the systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) using international guidelines. In this work, the BP simulation was performed on 64 waveforms, combinations of SBP (80–180 mmHg) and DBP (60–170 mmHg) to compute the BP in different health conditions such as hypotension, normal, and hypertension. In addition, an oscillometric waveform was also obtained from the brachial artery of a healthy person and analyzed for its utility as an NIBP waveform recorder. The SBP, DBP, and MBP were calculated from the oscillometric waveform envelope (OMWE) using the maximum amplitude algorithm (MAA) technique. In-house developed capacitive pressure sensors give comparable results when tested against the NIBP simulator and the commercial BP monitor. The pulse rate is also computed using the same OMW. The mean and standard deviation of the error in SBP, DBP, and MBP are within the universal standards' validation protocol for BP devices. The results indicate that the flexible capacitive pressure sensor can measure the BP with acceptable error and replace the commercial BP monitor and recorder sensor. The developed sensors show potential for large-scale clinical trials for blood pressure and pulse rate measurements.