Spectral Analysis of Central Venous Pressure Waveform

The use of central venous pressure, which is one of the static preload indices, has been abandoned for the assessment of intravascular volume status because of its unreliability. The static preload indices have been replaced with dynamic preload indices, such as stroke volume variation or pulse pressure variation because the dynamic preload indices reliably predict fluid responsiveness and perform better than the static preload indices. However, the periodic component of central venous pressure, which goes with cardiac cycles, has not been investigated. The power corresponding to heart rate from spectral analysis of central venous pressure waveform represents the extent of the dynamic fluctuation of central venous pressure and is assumed to reflect intravascular volume status. It is hypothesized that the spectral power of central venous pressure corresponding to heart rate represents intravascular volume status.