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.
6 Assignments
0 Petitions
Reexamination
Accused Products
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.
1471 Citations
15 Claims
-
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. - View Dependent Claims (2, 3, 4, 5, 6)
a smoothing filter for said data;
an adjustment for said smoothing filter that is a function of at least one of said signal quality measures;
a predetermined alarm threshold for said data; and
an alarm trigger responsive to said smoothing filter and said alarm threshold.
-
-
6. The indicator of claim 5 wherein said filter comprises:
-
a buffer having said data as an input and a delay output, wherein the delay output comprises said data time-shifted according to said adjustment;
a first comparator output responsive to said data and said threshold; and
a second comparator output responsive to said delay output and said threshold, said comparator outputs combined so as to provide said alarm trigger.
-
-
7. A data confidence indicator comprising:
-
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)
a first comparator output responsive to said data set and said threshold;
a second comparator output responsive to said delayed data set and said threshold; and
a combination of said comparator outputs providing an alarm trigger for said warning.
-
-
9. The data confidence indicator according to claim 8 further comprising a combination of said signal quality measures providing an alert trigger to generate a warning when confidence in said data set is low.
-
10. A data confidence indication method comprising the steps of:
-
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;
indicating on a display a level of confidence in said data set based upon at least one of said signal quality measures;
utilizing said signal Quality measures to detect a low signal Quality period during which time said data set may be compromised;
writing an alert message on said display during at least a portion of said low signal quality period;
comparing each of said signal quality measures to a corresponding one of a plurality of thresholds to generate a plurality of trigger inputs; and
combining said trigger inputs to trigger a low signal quality warning.
-
-
11. A data confidence indication method comprising the steps of:
-
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;
indicating on a display a level of confidence in said data set based upon at least one of said signal quality measures;
setting an alarm limit for said data set;
filtering said data set to generate an alarm trigger based upon said alarm limit; and
;
adjusting characteristics of said filtering step according to said signal quality measures so that more filtering is applied during said low signal quality period. - View Dependent Claims (12, 13)
time-shifting said data set to create a delayed data set;
comparing said data set to a threshold to generate a first trigger input;
comparing said delayed data set to said threshold to generate a second trigger input; and
combining said trigger inputs to generate said alarm trigger.
-
-
13. The data confidence indication method according to claim 12 wherein said adjusting comprises the substep of changing the amount of said time-shifting according to said signal quality measures.
-
14. A data confidence indication method comprising the steps of:
-
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, wherein delaying the alarm trigger comprises;
time-shifting said data set by a delay to generate a delayed data set, wherein said delay is a function of at least one of said signal quality measures;
comparing said data set to said threshold to create a first limit output;
comparing said delayed data set to said threshold to create a second limit output; and
combining said limit outputs to generate said alarm trigger.
-
-
15. A data confidence indication method comprising the steps of:
-
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;
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;
comparing each of said signal quality measures to a corresponding one of a plurality of thresholds to generate a plurality of trigger inputs; and
combining said trigger inputs to trigger a low signal quality warning.
-
Specification