Pulse oximetry data confidence indicator
First Claim
1. A data confidence indicator comprising:
- a plurality of physiological data and a plurality of signal quality measures derived from a physiological sensor output;
a plurality of comparator outputs each responsive to one of said measures and a corresponding one of a plurality of thresholds;
an alert trigger output combining said comparator outputs; and
a low signal quality warning generated in response to said alert trigger output, said thresholds set so that said warning occurs during a time period when there is low confidence in said data.
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Abstract
An intelligent, rule-based processor provides a pulse indicator designating the occurrence of each pulse in a pulse oximeter-derived photo-plethysmograph waveform. When there is relatively no distortion corrupting the plethysmograph signal, the processor analyzes the shape of the pulses in the waveform to determine where in the waveform to generate the pulse indication. When distortion is present, looser waveform criteria are used to determine if pulses are present. If pulses are present, the pulse indication is based upon an averaged pulse rate. If no pulses are present, no indication occurs. The pulse indicator provides a trigger and amplitude output. The trigger output is used to initiate an audible tone “beep” or a visual pulse indication on a display, such as a vertical spike on a horizontal trace or a corresponding indication on a bar display. The amplitude output is used to indicate data integrity and corresponding confidence in the computed values of saturation and pulse rate. The amplitude output can vary a characteristic of the pulse indicator, such as beep volume or frequency or the height of the visual display spike.
The visual pulse indicator is supplemented by a signal quality alert. Combined with several indicators of signal quality, the alert is used to initiate a warning when data confidence is very low. The alert may be in the form of a message generated on the pulse oximeter display to warn that the accuracy of saturation and pulse rate measurements may be compromised. A confidence-based alarm utilizes signal quality measures to reduce the probability of false alarms when data confidence is low and to reduce the probability of missed events when data confidence is high.
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Citations
18 Claims
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1. A data confidence indicator comprising:
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a plurality of physiological data and a plurality of signal quality measures derived from a physiological sensor output;
a plurality of comparator outputs each responsive to one of said measures and a corresponding one of a plurality of thresholds;
an alert trigger output combining said comparator outputs; and
a low signal quality warning generated in response to said alert trigger output, said thresholds set so that said warning occurs during a time period when there is low confidence in said data. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A data confidence indicator comprising:
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a processor configured to derive a time-dependent physiological data set and a plurality of time-dependent signal quality measures from a physiological signal;
a buffer configured to time-shift said data set by a delay to generate a delayed data set, said delay being a function of at least one of said signal quality measures;
a threshold setting a limit for said data set and said delayed data set; and
a warning generated when the levels of said data set and said delayed data set are beyond said threshold. - View Dependent Claims (8, 9)
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10. A data confidence indication method comprising the steps of:
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acquiring a signal from a physiological sensor;
calculating a physiological data set from said signal;
calculating a plurality of signal quality measures from said signal; and
indicating on a display the confidence in said data set based upon at least one of said signal quality measures. - View Dependent Claims (11, 12, 13, 14, 15, 17, 18)
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16. A data confidence indication method comprising the steps of:
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acquiring a signal from a physiological sensor;
calculating a physiological data set from said signal;
calculating a plurality of signal quality measures from said signal;
setting an alarm threshold for said data set; and
delaying an alarm trigger when said data set exceeds said threshold as a function of at least one of said signal quality measures so as to reduce the probability of false alarms.
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Specification