Extraction of the diagnostic parameters from the pulse plethysmogram during real-time continuous hemodynamic monitoring

Noninvasive continuous patient monitoring in real-time is considered to be the “Holy Grail” of hemodynamic assessment. Early detection of the changes in circulatory parameters prevents potential deseases, organ failures and death. For the purposes of the clinical patient surveillance this goal can be attained by enhancing of the pulse waveform analysis. Pulse oximetry is an established method for the noninvasive measurement of arterial blood saturation and pulse rate. With advances in digital signal processing its range can be expanded for the acquisition of extra diagnostic data. Software algorithms were tested on 46 patients in the dialysis station and intensive care unit (ICU). Continuous wavelet transform (CWT) was used as a tool for complete monitoring of the microdynamics at the sensor site. Spectrum of the microregulatory mechanisms can be represented in 3D-time window by means of the frequency allocation. Wavelet transforms applied to the pulse oximetry signals reveal a great potential for analysis of the cardiovasculatory processes in clinical environment.