United States Patent
`(12)
`(10) Patent No.:
`US 6,996,427 B2
`Ali et al.
`(45) Date of Patent:
`*Feb. 7, 2006
`
`
`US006996427B2
`
`(75)
`
`(54) PULSE OXIMETRY DATA CONFIDENCE
`INDICATOR
`Inventors: Ammar Al Ali, Tustin, CA (US); Divya
`S. Breed, Laguna Niguel, CA (US);
`Jerome J. Novak, Aliso Viejo, CA
`(US); Massi E. Kiani, Laguna Niguel,
`CA (US)
`
`DE
`a
`wo
`Wo
`wo
`WO
`wo
`
`FOREIGN PATENT DOCUMENTS
`3723566
`1/1989
`aoe
`ee
`WO 98/43071
`10/1998
`WO 00/38569
`72000
`WO 00/40147
`2000
`WO 00/56209
`9/2000
`WO 00761000
`10/2000
`
`;
`;
`(73) Assignee: Masimo Corporation, Irvine, CA (US)
`OTHER PUBLICATIONS
`(*) Notice:
`Subject to any disclaimer, the term of this
`Webster’s New World Dictionary of AMerican English,
`patent is extended or adjusted under 35
`:
`sa
`US.C. 154(b) by 0 days
`Webster’s New World , Third College Edition, p. 30.*
`eh
`y
`YS.
`
`
`
`
`Thi toaterminal ditent is subject Michael W. Wukitsch et al., “Pulse Oximetry: Analysis of
`clamor ent
`18 suoject
`10 a
`terminal
`cls-
`Theory, Technology, and Practice,” Journal of Clinical
`,
`Monitoring, vol. 4, No. 4, pp. 290-301 (Oct. 1998).
`2
`.
`(21) Appl. No.: 10/739,794
`* ciled by examiner
`(22) Filed:
`Dec. 18, 2003
`(65)
`Prior Publication Data
`ae |
`US 2004/0133087 Al Jul. 8, 2004
`Related U.S. Application Data
`(63) Continuation of application No. 09/858,114, filed on May
`15, 2001, nowPat. No. 6,684,090, which is a continuation-
`in-part of application No. 09/478,230,filed on Jan. 6, 2000,
`now Pat. No. 6,606,511.
`Provisional application No. 60/115,289, filed on Jan. 7,
`1999.
`Int. Cl.
`AGIB 5/00
`(2006.01)
`,
`.
`(52) US. Cle cescccceessssssssssessesssssssseteescen 600/310; 600/324
`(58) Field of Classification Paneer Ne.ay
`See
`application
`file
`for
`compl
`te search history,
`Se EPpheallon Wie
`LOT COMMPICNS Seareny
`DIStOTY.
`References Cited
`U.S. PATENT DOCUMENTS
`
`(60)
`
`(51)
`
`(56)
`
`Primary Examiner—Eric F. Winakur
`Assistant Examiner—Matthew Kremer
`(74) Attorney, Agent, or Firm—Knobbe, Martens, Olson &
`Bear LLP
`67)
`ABSTRACT
`physi
`£
`luralit
`fid
`A dat
`indi
`includ
`ala conlidence indicator includes a plurality of physi-
`ological data and a plurality of signal quality measures
`derived from a physiological sensor output, and a plurality
`of comparator outputs cach responsive to one of the mca-
`sures and a corresponding one of a plurality of thresholds.
`An alert trigger output combines the comparator outputs. A
`low signal quality warning is generated in response to the
`alert trigger output, wherein the thresholds are set so that the
`warningoccurs during a time period when there is low
`confidence in the data. The alert may be in the form of a
`message generated on the pulse oximeter display to warm
`that the accuracyof saturation and pulse rate measurements
`may be compromised. A confidenec-bascd 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.
`
`24 Claims, 24 Drawing Sheets
`
`3,875,930 A
`4,193,393 A
`
`4/1975 Silva et al.
`3/1980 Schlager
`
`(Continued)
`
`404
`
`t612
`
`
`
`PR_DENSITY
`405
`
`
`
`
`
`
`4EZ2
`
`
`
`HR
`HARMONIC RATIO
`COMPARATOR A<B
`A
`1550
`8
`
`
`HR_ THRESHOLD
`
`1652
`
`0001
`
`ALERT TRIGGER
`
`Apple Inc.
`APL1064
`U.S. Patent No. 8,923,941
`FITBIT, Ex. 1064
`
`Apple Inc.
`APL1064
`U.S. Patent No. 8,923,941
`
`0001
`
`FITBIT, Ex. 1064
`
`

`

`US 6,996,427 B2
`
`Page 2
`
`
`
`
`
`U.S. PATENT DOCUMENTS
`
`8/2000 Lepper, Jr. et al.
`6,110,522 A
`9/2000 Kaestle et al.
`6,122,535 A
`a
`11/2000 Kiani-Azarbayjany etal.
`6,151,516 A
`9/1980 Boschung
`4,222,044 A
`11/2000 Gerhardtet al.
`6,152,754 A
`9/1987 Hetyet
`4,694,200 A
`12/2000 Diab et al.
`6,157,850 A
`T1980 cate
`4800495 ‘s
`
`oreo spon eeet al
`9/1989 Flower etal.
`.
`w. 356/41
`4,863,265 A *
`
`oe On :
`. 600/323
`9/1989 Craig et al.
`....
`4,869,253 A *
`6,206,830 Bl
`3/2001 Diab ct al.
`10/1990 Gordonetal.
`4,960,128 A
`6,229,856 Bl
`5/2001 Diab et al.
`5/1991 Beckers veces 600/316
`5,019,974 A *
`6,236,872 B
`5/2001 Diab etal.
`11/1992 Gordonetal.
`5,163,438 A
`6,256,523 B
`7/2001 Diab et al.
`3/1993 Wakabayashi
`5,199,048 A
`6,263,222 B
`7/2001 Diab et al.
`9/1993 DeLonzor
`5,246,003 A
`6,278,522 B
`8/2001 Lepper, In. etal.
`3/1994 Kaestle
`5,299,120 A
`6,280,213 B
`8/2001 Tobleretal.
`8/1994 Branigan
`5,337,744 A
`6,285,896 B
`9/201 Tobleretal.
`12/1994 Richardson
`5,372,134 A
`6,334,065 B1
`12/2001 AI-Ali et al.
`7/1995 Mathews
`5,431,170 A
`6,339,715 B
`1/2002 Bahrctal.
`9/1995 Branigan ct al.
`5,452,717 A
`6,349,228 B
`2/2002 Kianietal.
`1/1996 Diab etal.
`5,482,036 A
`6,360,114 B
`3/2002 Diab etal.
`1/1996 Baker, Jt. cece 600/323
`5,485,847 A *
`6,371,921 B
`4/2002 Caro et al.
`2/1996 Diab etal.
`5,490,505 A
`6,377,829 B
`4/2002 Al-Ali
`2/1996 O*Sullivan et al.
`5,494,043 A
`6,388,240 B2
`5/2002 Schulz ctal.
`5/1996 Gerhard
`5,517,988 A
`
`
`
`5,533,511 A 5/2002-Diabet al.7/1996 Kaspari etal. 6,397,091 B2
`
`.. 600/323
`5,590,649 A
`1/1997 Caro etal.
`6,415,166 B
`7/2002 Van Hoyet al.
`.
`
`1/1997 Yamaura oocscsceseecceceees 600/323
`5,595,176 A *
`6,430,525 B
`8/2002 Weberetal.
`
`vee 600/323
`5,632,272 A *
`5/1997 Diabetal...
`6,463,311 B1
`10/2002 Diab
`5,638,816 A
`6/1997 Kiani-Azarbayjanyct al.
`6,470,199 B
`10/2002 Kopotic ctal.
`5,638,818 A
`6/1997 Diab et al.
`6,501,975 B2
`12/2002 Diabetal.
`5,645,440 A
`7/1997 Tobleretal.
`6,515,273 B2
`2/2003 ALAli
`5,685,299 A
`11/1997 Diabetal.
`6,525,386 B
`2/2003. Mills etal.
`D393,830 S
`4/1998 Tobleretal.
`6,526,300 B
`2/2003 Kianietal.
`5,743,262 A
`4/1998 Lepper, Jr. ct al.
`6,541,756 B2
`4/2003 Schulz ctal.
`5,751,911 A
`5/1998 Goldman
`6,542,764 B
`4/2003 AI-Ali et al.
`5,758,644 A
`6/1998 Diab etal.
`6,580,086 B
`6/2003 Schulz etal.
`5,760,910 A
`6/1998 Lepper, Ir. etal.
`6,584,336 B
`6/2003 Ali etal.
`5,769,785 A
`6/1998 Diab et al.
`6,597,933 B2
`7/2003 Kianiet al.
`5,782,757 A
`7/1998 Diab ctal.
`6,606,511 B
`8/2003 Alii ctal.
`5,785,659 A
`7/1998 Caro et al.
`6,632,181 B2
`10/2003 Flaherty et al.
`5,791,347 A
`8/1998 Flaherty et al.
`6,640,116 B2
`10/2003 Diab
`5,810,734 A
`9/1998 Caro etal.
`6,643,530 B2
`11/2003 Diabet al.
`5,810,740 A *
`9/1998 Paisner voces 600/515
`6,650,917 B2
`11/2003 Diabetal.
`5,819,007 A
`10/1998 Elghazzawi
`6,654,624 B2
`11/2003 Diabctal.
`5,823,950 A
`10/1998 Diabetal.
`6,658,276 B2
`12/2003 Pishneyetal.
`5,830,131 A
`11/1998 Caro etal.
`6,671,531 B2
`12/2003 ALAli etal.
`5,830,135 A
`11/1998 Bosqueetal.
`6,678,543 B2
`1/2004 Diabet al.
`
`5,833,618 A 6,684,090 B2*1/2004 Ali et dl. veces 600/32311/1998 Caroetal.
`
`5,860,919 A
`1/1999 Kiani-Azarbayjany ctal.
`6,697,656 B1
`2/2004 Al-Ali
`5,865,736 A
`2/1999 Baker, Jr. el al.
`6,697,658 B2
`2/2004 Al-Ali
`5,890,929 A
`4/1999 Mills et al.
`RE38,476 E
`3/2004 Diab et al.
`5,904,654 A
`5/1999 Wohltmannetal.
`6,699,194 B1
`3/2004 Diabet al.
`5,919,134 A
`7/1999 Diab
`6,714,804 B2
`3/2004. Al-Ali et al.
`5,934,925 A
`8/1999 Tobler etal.
`RE38,492 E
`4/2004 Diab ct al.
`5,940,182 A
`8/1999 Lepper, Jr.etal.
`6,725,075 B2
`4/2004 Al-Ali
`5,967,994 A * LO/L999 Wang vescscessscssereseeeees 600/509
`6,745,060 B2
`6/2004 Diabetal.
`5,995,855 A
`11/1999 Kianietal.
`6,760,607 B2
`7/2004 AL-All
`5,997,343 A
`12/1999 Millset al.
`6,770,028 B1
`8/2004 Ali etal.
`6,002,952 A
`12/1999 Diab etal.
`6,771,994 B2
`8/2004 Kianictal.
`6,006,119 A * 12/1999 Soller el al. cece 600/322
`6,792,300 Bl
`9/2004 Diabetal.
`6,011,986 A
`1/2000 Diab etal.
`6,813,511 B2
`11/2004 Diabetal.
`6,027,452 A
`2/2000 Flaherty etal.
`6,816,741 B2
`11/2004 Diab
`6,036,642 A
`3/2000 Diab etal.
`6,822,564 B2
`11/2004 AL-Ali
`6,045,509 A
`4/2000 Caro etal.
`6,826,419 B2
`11/2004 Diabetal.
`6,047,201 A *
`4/2000 Jackson, II ...
`6,830,711 B2
`12/2004 Mills etal.
`6,067,462 A
`5/2000 Diab etal.
`6,850,787 B2
`2/2005 Weberetal.
`6,080,111 A *
`6/2000 Pao-Lang occ. cecceee: 600/503
`6,850,788 B2
`2/2005 Al-Ali
`6,081,735 A
`6/2000 Diab etal.
`6,852,083 B2
`2/2005 Caroet al.
`6,083,172 A
`7/2000 Baker, Jr. et al.
`6,861,639 B2
`3/2005 Al-Ali
`6,088,607 A
`7/2000 Diab etal.
`6,898,452 B2
`5/2005 Al-Aliet al.
`
`
`
`
`.. 600/344
`
`0002
`
`FITBIT, Ex. 1064
`
`0002
`
`FITBIT, Ex. 1064
`
`

`

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`US 6,996,427 B2
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`730,140
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`160
`
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`US 6,996,427 B2
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`US 6,996,427 B2
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`4500
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` SIGNAL 1370 INTEG
`
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`
`QUALITY
`PR DENSITY
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`
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`PHYSIOLOGICAL DATA (PD)
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`SIGNAL QUALITY MEASURE (SQM)
`BASED
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`ALARM THRESHOLD
`ALARM
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`ALERT TRIGGER
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`US 6,996,427 B2
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`1
`PULSE OXIMETRY DATA CONFIDENCE
`INDICATOR
`
`This application is a continuation of application Ser. No.
`09/858,114, filed May 15, 2001, now US. Pat. No. 6,684,
`090, which is a continuation-in-part of application Ser. No.
`09/478,230,filed Jan. 6, 2000, now U.S. Pat. No. 6,606,511,
`which claimsthe benefit of U.S. Provisional Application No.
`60/115,289, filed Jan. 7, 1999.
`
`rn
`
`10
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`2
`physiological conditions including heart stroke volume,
`pressure gradient, arterial elasticity and peripheral resis-
`tanec. The ideal waveform 100 displays a broad pcriphcral
`flow curve, with a short, steep inflow phase 130 followed by
`a 3 to 4 times longer outtlow phase 140. ‘he inflow phase
`130 is the result of tissue distention by the rapid blood
`volume inflow during ventricular systole. During the out-
`flow phase 140, blood flow continues into the vascular bed
`during diastole. The end diastolic baseline 150 indicates the
`minimumbasal tissue perfusion. During the outflow phase
`140 is a dicrotic notch 160, the nature of which is disputed.
`Classically, the dicrotic notch 160 is attributed to closure of
`the aortic valve at the end of ventricular systole. However,
`it may also be the result of reflection from the periphery of
`an initial, fast propagating, pressure pulse that occurs upon
`the opening of the aortic valve and that precedes the artcrial
`flow wave. A double dicrotic notch can sometimes be
`
`observed, although its explanation is obscure, possibly the
`
`
`
`result of reflections reaching the sensor at different times.
`FIGS.2-4 illustrate plethysmograph waveforms 200, 310,
`360 that display various anomalies. In FIG. 2, the waveform
`200 displays two arrhythmias 210, 220.
`In FIG. 3,
`the
`waveform 310 illustrates distortion corrupting a conven-
`tional plethysmograph 100 (FIG. 1). FIG. 4 showsa filtered
`waveform 360 after distortion has been removed through
`adaptive filtering, such as described in U.S. Pat. No. 5,632,
`272 cited above. FIG. 4 illustrates that, although the wave-
`form 360is filtered, the resulting pulses 362 have shapesthat
`are distorted in comparison to the pulses illustrated in FIG.
`1.
`
`A desirable feature of pulse oximelers is an audible
`“beep” tone produced to correspond to the patient’s pulse.
`Conventionally, the beep is triggered from recognition of
`some aspect of the plethysmograph waveform shape. Such
`a waveform-triggered beep may indicate an arrhythmia,like
`those displayed in FIG. 2, but may also generate false pulse
`indications as the result of motion-artifact or noise induced
`waveform distortion, as illustrated in FIGS. 3 and 4. This
`characteristic results because both distortion and arrhyth-
`mias result in anomalies in the plethysmograph waveform
`shape on which this beep mechanism is dependent.
`Alternatively, the becp can be triggered from a time basc sect
`to the average pulse rate. Signal processing can generate an
`average pulserate that is resistant to distortion induced error.
`A pulse beep based on average pulse rate is relatively
`insensitive to episodes of distortion, but is likewise insen-
`sitive to arrhythmias.
`An example of the determination of pulse rate in the
`presence of distortion is described in U.S. Pat. No. 6,002,
`952, filed Apr. 14, 1997, entitled “Signal Processing Appa-
`ratus and Method,” which is assigned to the assignee of the
`current application and incorporated by reference herein.
`Another example of pulsc rate determination in the presence
`of distortion is described in U.S. patent application Ser. No.
`09/471,510, filed Dec. 23, 1999, entitled “Plethysmograph
`Pulse Recognition Processor,” which is assigned to the
`assignee of the current application and incorporated by
`reference herein.
`
`Once aspect of the present invention is a processor having
`a decision elementthat determinesif the waveform haslittle
`or no distortion or significant distortion. If there is little
`distortion, the decision element provides a trigger in real-
`time with physiologically acceptable pulses recognized by a
`waveform analyzer. If there is significant distortion, then the
`decision element providesthe trigger based synchronized to
`an averaged pulse rate, provided waveform pulses are
`detected. The trigger can be used to generate an audible
`
`
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`
`‘This application generally relates to devices and methods
`for measuring physiological data, and more particularly to
`devices and methods of presenting this data.
`2. Description of the Related Art
`Oximetry is the measurement of the oxygen status of
`blood. Early detection of low blood oxygenis critical in the
`
`medical field, for example in critical care and surgical
`
`applications, because an insufficient supply of oxygen can
`result in brain damage and death in a matter of minutes.
`Pulse oximetryis a widely accepted noninvasive procedure
`for measuring the oxygen saturation level ofarterial blood,
`bomn
`an indicator of oxygen supply. A pulse oximeter typically 7
`provides a numerical
`rcadout of the paticnt’s oxygen
`saturation, a numerical readout of pulse rate, and an audible
`indicator or “beep” that occurs in response to each pulse. In
`addition, a pulse oximeter may display the patient’s plethys-
`mograph waveform, which is a visualization of blood vol-
`ume change in the illuminated tissue caused bypulsatile
`arterial blood flow over time. The plethysmograph provides
`a visual displaythat is also indicative of the patient’s pulse
`and pulse rate.
`A pulse oximetry system consists of a sensor attached to
`a patient, a monitor, and a cable connecting the sensor and
`monitor. Conventionally, a pulse oximetry sensor has both
`red and infrared (IR) light-emitting diode (LED) emitters
`and a photodiode detector. The sensoris typically attached
`to a patient’s fingeror toe, or a very young patient’s patient’s
`foot. For a finger, the sensor is configured so that the emilters
`project light through the fingernail and into the blood vessels
`and capillaries underneath. The photodiade is positioned at
`the fingertip opposite the fingernail so as to detect the LED
`transmitted light as it emerges from the finger tissues.
`‘The pulse oximetry monitor (pulse oximeter) determines
`oxygen saturation by computing the differential absorption
`by arterial blood of the two wavelengths emitted by the
`wn5
`_
`sensor. The pulse oximeter alternately activates the sensor
`LED emitters and reads the resulting current generated by ©
`the photodiode detector. This current is proportional to the
`intensity of the detected light. The pulse oximeter calculates
`a ratio of detected red and infrared intensities, and an arterial
`oxygen saturation value is empirically determined based on
`the ratio obtained.‘The pulse oximeter contains circuitry for
`controlling the sensor, processing the sensor signals and
`displaying the patient’s oxygen saturation and pulse rate. A
`pulse oximeter is described in U.S. Pat. No. 5,632,272
`assigned to the assignee of the present invention.
`
`60
`
`SUMMARYOF THE INVENTION
`
`TIG. 1 illustrates the standard plethysmograph waveform
`100, which can be derived from a pulse oximeter. The
`waveform 100 is a display of blood volume, shown along the
`y-axis 110, over time, shown along the x-axis 120. The shape
`of the plethysmograph waveform 100 is a function of
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`3
`is insensitive to episodes of significant
`pulse beep that
`distortion,but is capable of responding to arrhythmia events.
`Another desirable feature for pulse oximeters is a visual
`indication of the patient’s pulse. Conventionally,
`this is
`provided by an amplitude-versus-time display of the
`plethysmograph waveform, such as illustrated in FIG. 1.
`Some monitors are only capable of a light-bar display of the
`plethysmograph amplitude. Regardlcss, both types of dis-
`plays provide a sufficient indication of the patient’s pulse
`only whenthereis relatively small distortion of the plethys-
`mograph waveform. When there is significant distortion,
`such as illustrated in [IG. 3A, the display provides practi-
`cally no information regarding the patient’s pulse.
`Yet another desirable feature for pulse oximeters is an
`indication of confidence in the input data. Conventionally, a
`visual display of a plethysmograph waveform that shows
`relatively small distortion would convey a high confidence
`level in the input data and a corresponding high confidence
`in the saturation and pulse rate outputs of the pulse oximeter.
`Ilowever, a distorted waveform doesnot necessarily indicate
`low confidence in the input data and resulting saturation and
`pulse rate outputs, especially if the pulse oximeter is
`designed to function in the presence of motion-artifact.
`Another aspect of the current invention is the generation
`of a data integrity indicator that is used in conjunction with
`the decision element trigger referenced above to create a
`visual pulse indicator.
`‘The visual pulse indicator is an
`amplitude-versus-time display that can be provided in con-
`junction with the plethysmograph waveform display. The
`trigger is used to generale a amplitude spike synchronousto
`a plethysmograph pulse. The data integrity indicator varies
`the amplitude of the spike in proportion to confidence in the
`measured values.
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`
`Yet another aspect of the present invention is a processing
`apparatus that has as an input a plethysmograph waveform
`containing a plurality of pulses. The processor generates a
`trigger synchronous with the occurrence of the pulses. The
`processor includes a waveform analyzer having the wave-
`form as an input and responsive to the shape of the pulses.
`The processoralso includes a decision element responsive to
`the waveform analyzer output when the waveform is sub-
`stantially undistorted and responsive to pulse rate when the
`waveform is substantially distorted. ‘The trigger can be used
`to gencratc an audible or visual indicator of pulse occur-
`rence. A measure of data integrity can also be used to vary
`the audible or visual indicators to provide a simultaneous
`indication of confidence in measured values, such as oxygen
`saturation and pulse rate.
`wn5
`A further aspect of the current invention is a method of 5
`indicating a pulse in a plethysmograph waveform.
`‘lhe
`methodincludesthe steps of deriving a measure of distortion
`in the waveform, establishing a trigger criterion dependent
`on that measure, determining whetherthe triggercriterion is
`satisfied to provide a trigger, and generating a pulse indica-
`tion upon occurrence of the trigger. The deriving step
`includes the sub-steps of computing a first value related to
`the waveform integrity, computing a second value related to
`the recognizable pulses in the waveform, and combining the
`first and second values to derive the distortion measure. ‘The
`trigger critcrion is based on waveform shape and possibly on
`an averaged pulserate.
`One more aspect of the current invention is an apparatus
`for indicating the occurrence of pulses in a plethysmograph
`waveform. This apparatus includes a waveform analyzer
`means for recognizing a physiological pulse in the wave-
`form. Also included is a detector means for determining a
`
`QDa
`
`4
`measure of distortion in the waveform and a decision means
`for triggering an audible or visual pulse indicator. The
`decision means is based the physiological pulse and possibly
`the pulse rate, depending on the distortion measure.
`Another aspect of the present invention is a data confi-
`dence indicator comprising a plurality of physiological data
`and a plurality of signal quality measures derived from a
`physiological sensor output. A plurality of comparator out-
`puts are each responsive to one of the measures and a
`corresponding one of a plurality of thresholds. An alert
`trigger oulpul combines said comparator outputs, and a low
`signal quality warning is generated in responseto said alert
`trigger output. The thresholds are sct so that the warning
`occurs during a time period when there is low confidence in
`the data.
`In one embodiment,
`the warning is a display
`message that supplements a visual pulse indicator,
`the
`display message specifies a low signal quality when the
`visual pulse indicator has an amplitude that is less than
`one-third full-scale. In another embodiment, the signal qual-
`ily Measures are an inlegrily measure, a pulse rate densily
`measure and a harmonic ratio measure.
`In a particular
`embodiment, the thresholds may have an integrity valuc of
`less than 0.3, a pulse rate density value of less than 0.7 and
`a harmonicratio value of less than 0.8.
`In yet another embodimenta filter for the data generates
`a smoothed data output. An adjustment for the smoothed
`data output is a function of at least one of the signal quality
`measures so that smoothing at the smoothed data output
`increases when at least one of the signal quality measures
`decreases. An alarm trigger is responsive to the smoothed
`data outpul so as to generate an alarm when the smoothed
`data output is outside of a predetermined limit. In a particu-
`lar embodiment the filter comprises a buffer having a buffer
`input and a delayoutput. The buffer input correspondsto the
`data and the delay output is time-shifted according to the
`adjustment. A first filter comparator output is responsive to
`the data and a data threshold, and a second filter comparator
`output is responsive to the delay output and a delay output
`threshold. The comparator outputs are combined so as to
`provide the alarm trigger.
`A further aspect of the present invention is a data confi-
`dence indicator comprising a processor configured to derive
`a time-dependent physiological data set and a plurality of
`time-dependent signal quality measures from a physiologi-
`cal signal. A buffer is configured to time-shift the data set by
`a delay to generate a delayed data set, where the delay is a
`function of at least one of the signal quality measures. The
`indicator has a threshold setting a limit for the delayed data
`set. A warning is generated when the levels of the data set
`and the delayed data set are beyond that threshold. In one
`embodiment, a first comparator output is responsive to the
`data and the threshold, and a second comparator output is
`responsive to the delayed data sct and the threshold. A
`combination of the first and second comparator outputs
`provides an alarm trigger for the warning. The data confi-
`dence indicator may also comprise a combination of the
`signal quality measures providingan alert trigger to generate
`warning when confidence in the data set is low.
`An additional aspect of the present invention is a data
`confidence indication method comprising the steps of
`acquiring a signal from a physiological sensor, calculating a
`physiological data set from the signal, calculating signal
`quality measures from the signal, and indicating on a display
`the confidence in the data set based upon at least one of the
`signal quality measures. The indicating step may have the
`substeps of utilizing the signal quality measures to detect a
`lowsignal quality period during whichtime the data set may
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`5
`be compromised, and writing an alert message on the display
`during at least a portion of that period. Additional utilizing
`substeps may include comparing each of the signal quality
`measures to a corresponding one ofa plurality of thresholds
`to generate a plurality of trigger inputs and combining the
`trigger inputs to trigger a low signal quality warning. Addi-
`tional steps mayinclude setting an alarm limit for the data
`set, filtering the data set to generate an alarm trigger based
`upon the alarm limit and adjusting the characteristics of the
`filtering step according to at least one of the signal quality
`measures so that more filtering is applied during the low
`signal quality period. In one embodiment,the filtering step
`compriscs the substepsof time-shifting the data sct to create
`a delayed data set, comparing the data set to a threshold to
`generate a first trigger input, comparing the delayed data set
`to the threshold to generate a second trigger input, and
`combining the trigger inputs to generate the alarm trigger.
`Yet a further aspect of the present invention is a data
`confidence indication mcthod comprising the steps of
`acquiring a signal from a physiological sensor, calculating a
`physiological data set from the signal, calculating a plurality
`of signal quality measures fromthe signal, setting an alarm
`threshold for the data set, and delaying an alarm trigger
`when the data set exceeds the threshold as a function of at
`least one of the signal quality measures so as to reduce the :
`probability of false alarms. In one embodiment, the delaying
`step comprises the substeps of time-shifting the data set by
`a delay to generate a delayed data sct, where the delay is a
`function of at least one of said signal quality measures, and
`comparing the data set to the thresholdto createa first limit
`output. Further substeps include comparing the delayed data
`set
`to the threshold to create a second limit output and
`combining the limit outputs to generate the alarm trigger.
`The data confidence indication method mayfurther com-
`prise the steps of comparing each of the signal quality
`measures to a corresponding one of a plurality of thresholds
`to generate a plurality of trigger inputs and combining the
`trigger inputs to trigger a low signal quality warning.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`10
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`15
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`30
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`35
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`40
`
`FIG. 1 illustrates a standard plethysmograph waveform
`that can be derived from a pulse oximeter;
`FIG.2 illustrates a plethysmograph waveform showing an
`arrhythmia;
`TIG. 3A illustrates a plethysmograph waveform corrupted
`by distortion;
`FIG. 3B illustrates a filtered plethysmograph correspond-
`ing to the distortion-corrupted plethysmograph of FIG. 3A;
`FIG. 4 illustrates the inputs and outputs of the pulsc
`indicator according to the present invention;
`FIGS. 5A-Billustrate the generation of one of the pulse
`indicator inputs;
`FIG.6 is a top-level block diagram of the pulse indicator;
`FIG. 7 is a detailed block diagram ofthe “distortion level”
`portion of the pulse indicator;
`FIG.8 is a block diagram ofthe infinite impulse response
`GIR) filters of the “distortion level” portion illustrated in
`FIG. 7;
`FIG. 9 is a detailed block diagram of the “waveform
`analyzer” portion of the pulse indicator;
`FIG. 10 is a detailed block diagram of the “slope calcu-
`lator”portion of the waveformanalyzerillustrated in FIG. 9;
`FIG. 11 is a detailed block diagram of the “indicator
`decision” portion of the pulse indicator;
`FIG.12 is a display illustrating a normal plethysmograph
`and a corresponding visual pulse indicator;
`
`wn5
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`60
`
`65
`
`6
`FIG. 13 is a display illustrating a distorted plethysmo-
`graph and a corresponding high-confidence-level visual
`pulse indicator;
`FIG. 14 is a display illustrating a distorted plethysmo-
`graph and a corresponding low-confidence-level visual
`pulse indicator;
`FIG. 15 is an input and output block diagram of a signal
`quality alert;
`FIG. 16 is a functional block diagram of a signal quality
`alert;
`FIG. 17 is an input and output block diagram of a
`confidence-based alarm;
`FIG. 18 is a functional block diagram of a confidence-
`based alarm; and
`FIGS. 19A—-Dare saturation versus time graphsillustrat-
`ing operation of a confidence-bascd alarm.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`
`FIG. 4 illustrates a pulse indicator 400, which can be
`incorporated into a pulse oximeter to trigger the occurrence
`of a synchronousindication of each of the patient’s arterial
`pulses. The indicator 400 operates on an IR signal input 403
`and generates a trigger output 409 and an amplitude output
`410. The trigger output 409 can be connected to a tone
`generator within thc pulse oximeter monitor to create a
`fixed-duration audible “beep” as a pulse indication.
`Alternatively, or in addition,
`the trigger output can be
`connected to a display generator within the pulse oximeter
`monitor to create a visual pulse indication. The visual pulse
`indication can be a continuous horizontal t