Evaluation of step interpolation of systolic arterial blood pressure signals

Power spectral analysis of systolic arterial blood pressure variability (SAPV) provides a window to the activity of the autonomic nervous system when used in conjunction with heart rate variability (HRV) spectral techniques. To derive power spectra from raw blood pressure signals, many steps of signal processing must be performed. Most popular methods of spectral analysis such as the FFT require evenly spaced samples; therefore interpolation and resampling techniques must be used. Since various resampling techniques introduce biasing to resulting spectra, it was determined that when comparing HRV spectra to SAPV spectra, the same interpolation methods should be used for both. It was found that step interpolation of systolic blood pressures results in spectra that are similar in content to that of the corresponding raw blood pressure signal due to the inclusion of HRV components