Circulation monitoring system and method
First Claim
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1. 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.
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Abstract
A lightweight portable probe or transducer containing a transmissive or reflective electro-optical emitter and receptor in the infrared spectrum is fitted on a subject'"'"'s finger or toe. Associated electronics energize and monitor the probe, detect cardio-rhythmic fluctuations therefrom, and process digital data over a prescribed window to produce a non-invasive, qualitative or quantitative measure of the subject'"'"'s circulation. In accordance with one embodiment of the invention, a simple tri-color LED array is used to indicate the subject'"'"'s circulation as being normal, reduced, or borderline.
45 Citations
15 Claims
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1. Circulation monitoring apparatus comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification