Generalized transfer functions are available to mathematically derive the more relevant central blood pressure waveform from a more easily measured radial blood pressure waveform. However, these transfer functions are population averages and therefore may not adapt well to variations in pulse pressure amplification (ratio of radial to central pulse pressure). An adaptive transfer function was developed. First, the transfer function is represented in terms of the wave travel time and wave reflection coefficient parameters of an arterial model. Then, the model parameters are estimated from only the radial blood pressure waveform by exploiting the frequent observation that central blood pressure waveforms exhibit exponential diastolic decays. The adaptive transfer function estimated central blood pressure with significantly greater accuracy than generalized transfer functions in the low pulse pressure amplification group while showing similar accuracy to the conventional transfer functions in the higher pulse pressure amplification groups.
