Patent ID: 7628760

Claim:
Circulation monitoring apparatus comprising: a transducer configured to illuminate and monitor light fluctuations through tissue within an anatomical extremity to produce a signal indicative of the fluctuations, the transducer including a photo emitter for emitting a light signal to illuminate the extremity and a photo receptor for receiving a light signal responsive thereto; a processor operatively coupled with the transducer, the processor configured to analyze the signal for periodicity and to measure the signal for amplitude, wherein the processor executes memory-based instructions including: instructions for DC level component removal from the signal; instructions for auto-correlating the signal; instructions for windowing the signal; instructions for producing a discrete Fourier transform (DFT) of the signal; and instructions for calculating the spectral flatness measure (SFM) of the signal; a comparator operatively coupled with the processor, the comparator configured to compare the measured amplitude of the signal to one or more predefined threshold amplitudes; and an indicator operatively coupled with the comparator, the indicator configured to indicate a circulation level from the comparator.