Artifact rejector for repetitive physiologic-event-signal data

• US 6,405,076 B1
• Filed: 07/29/1999
• Issued: 06/11/2002
• Est. Priority Date: 09/20/1995
• Status: Expired due to Term

• Current Assignee: Protocol Systems Inc
• Original Assignee: Protocol Systems Inc
• Inventors: Bennett, Ronald G., Dorsett, Thomas J., Taylor, Lee A.
• Primary Examiner(s): EVANISKO, GEORGE ROBERT
• Application Number:
  US09/364,272
• Time in Patent Office: 1,048 Days
• Field of Search: 128/901, 600/485, 600/493-496, 600/500, 600/490, 600/513
• US Class Current: 600/513
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/346 Analysis of electrocardiograms
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: Y10S 128/901 Suppression of noise in electric signal

Abstract

An artifact rejector for repetitive physiologic-event-signal data generated from electronically-controlled physiologic-event-measuring equipment includes a physiologic-event-signal averager in communication with such physiologic-event-measuring equipment. The artifact rejector is constructed to generate and store repetitive averaged physiologic-event-signal data based upon a substantially stable time relationship between corresponding physiologic-event-signal data and heart-beat-related-signal data. The repetitive averaged physiologic-event-signal data includes less noise than the repetitive physiologic-event-signal data. The artifact rejector generates and continuously updates an averaged-data template by storing such repetitive averaged physiologic-event-signal data for a preselected number of measured physiologic events. The artifact rejector also includes a physiologic-event-noise estimator and a physiologic-event-noise monitor in communication with such physiologic-event-measuring equipment, and capable of instructing the monitor to adjust the measurement cycle based upon estimated, monitored noise. The averager preferably includes a sharp roll-off, low pass filter and examples include a fourth-order Bessel filter, two cascaded, identical second-order Bessel filters, an elliptic filter, a Tchetschebyscheff filter, or finite impulse response filters. The heart-beat-related signal is preferably an ECG signal. A method of artifact rejection includes generating and storing repetitive averaged physiologic-event-signal data based upon a substantially stable time relationship between corresponding physiologic-event-signal data and heart-beat-related-signal data, with the repetitive averaged physiologic-event-signal data including less noise than the repetitive physiologic-event-signal data.

Claims

1. An artifact rejector for repetitive physiologic-event-signal data generated from physiologic-event-measuring equipment, which equipment also generates repetitive heart-beat-related-signal data during a physiologic-event measurement cycle, comprising:

physiologic-event-measuring equipment constructed to measure physiologic events of a patient, the equipment also being constructed to generate repetitive physiologic-event signal data and heart-beat-related signal data during a physiologic-event measurement cycle;

a physiologic-event-signal averager in communication with the physiologic-event-measuring equipment, and constructed to generate and store repetitive averaged physiologic-event-signal data based upon a substantially stable time relationship between corresponding repetitive physiologic-event-signal data and heart-beat-related-signal data, wherein the repetitive averaged physiologic-event-signal data includes less noise than the repetitive physiologic-event-signal data, and constructed to generate and continuously update an averaged-data template by storing the repetitive averaged physiologic-event-signal data monitored for a preselected time interval after an occurrence of the heart-beat-related signal; and

wherein the physiologic-event-signal averager also includes a sharp roll-off, low pass filter, and wherein the averager is constructed to adjust the filter based upon the physiologic-event-measurement cycle as a way of promoting accurate measurement of physiologic-event parameters by the physiologic-event-measuring equipment.

2. The artifact rejector of claim 1, wherein the filter is chosen from the group consisting of a fourth-order Bessel filter, two cascaded, identical second-order Bessel filters, an elliptic filter, a Tchetschebyscheff filter, or finite impulse response filters.

3. An artifact rejector for repetitive NIBP-oscillometric-signal data generated from electronically-controlled oscillometric-NIBP-measuring equipment, which equipment also generates repetitive heart-beat-related-signal data during an NIBP-measurement cycle that is characterized as measuring desired NIBP parameters by monitoring the repetitive NIBP-oscillometric-signal data corresponding to measured NIBP pulses at decreasing pressures according to an NIBP-measurement cycle, comprising:

electronically-controlled oscillometric-NIBP-measuring equipment constructed to measure blood pressure of a patient, the equipment being constructed to generate repetitive NIBP-oscillometric-signal data and repetitive heat-beat-related signal data during an NIBP-measurement cycle that is characterized as measuring desired NIBP parameters by monitoring the repetitive NIBP-oscillometric signal data corresponding to measured NIBP pulses at decreasing pressures according to an NIBP-measurement-cycle rate;

an NIBP-oscillometric-signal averager in communication with the NIBP-measuring equipment, and constructed to generate repetitive averaged NIBP-oscillometric-signal data based upon a substantially stable time relationship between corresponding NIMP-oscillometric-signal data and heart-beat-related-signal data, wherein the repetitive averaged NIBP-oscillometric-signal data includes less noise than the repetitive NIBP-oscillometric-signal data, and constructed to generate and continuously update an averaged-data template by storing the repetitive averaged NIBP-oscillometric-signal data for a number of measured NIBP pulses; and

wherein the NIBP-oscillometric-signal averager includes a sharp roll-off, low pass filter.

4. The artifact rejector of claim 3, wherein the NIBP-oscillometric-signal averager is constructed to adjust the filter based upon the NIBP-measurement-cycle rate as a way of promoting accurate measurement of NIBP parameters by such NIBP-measuring equipment.

5. The artifact rejector of claim 4, wherein the filter is chosen from the group consisting of a fourth-order Bessel filter, two cascaded, identical second-order Bessel filters, an elliptic filter, a Tchetschebyscheff filter, or finite impulse response filters.