Ultrasonic method and apparatus for measuring or detecting flow behavior of a non-sinusoidal periodicity

A method of operating a defibrillation unit that utilizes an ultrasonic method for detecting and/or measuring pulsatile flow comprising:

• acquiring ultrasonic Doppler signal information from a flow site;
• determining from the Doppler signal information a power spectrum within a specific frequency band that comprises a banded Doppler signal;
• identifying a fundamental and a plurality of harmonic peaks of the power spectrum of the banded Doppler signal within a plurality of discrete frequency ranges (i) that represent portions of the banded Doppler signal in which only periodic flow is present and (ii) that do not overlap;
• determining a ratio of power of (i) the Doppler signal to (ii) baseline noise for each of the plurality of discrete frequency ranges that do not overlap and in which the fundamental and harmonic peaks of the power spectrum of the banded Doppler signal have been identified;
• determining a measure of pulsatility of the pulsatile flow from a sum total of the power ratios of the Doppler signal to baseline noise determined for each of the plurality of discrete frequency ranges that do not overlap and in which the fundamental and harmonic peaks of the power spectrum of the banded Doppler signal have been identified;
• and
• controlling a defibrillation procedure, via a controller of the defibrillation unit, in response to the determined measure of pulsatility of the pulsatile flow.