Applications of Infrared Plethysmograph Waveform Time-Frequency Analysis

In the past, when patients were taking computed tomography (CT) scan, the physician usually monitored the patients on-site as a passive way; however, the entire physiological conditions of the patients couldn’t be fully comprehended this way. According to many clinical reports, the heart rates of the patients under tomography may fluctuate because of the injection of contrast medium. A standard pulse oximeter is usually used to measure the variation of heart rates. The problem is, the measured signal waveform could be distorted if the patients move their fingers or toes, or the connections of probes are loose. In this dissertation, several different time-frequency analysis methods will be used to explore the instantaneous frequency fluctuation of infrared plythysmograph waveform. We hope to find a feasible and direct time-frequency analysis to apply to monitoring patients’ physiological conditions.