United States Patent
`US 6,415,166 B1
`(10) Patent No.:
`(12)
`Van Hoyetal.
`(45) Date of Patent:
`Jul. 2, 2002
`
`
`US006415166B1
`
`(54) PHOTOPLETHYSMOGRAPHIC DEVICE
`WITH REMOTE FACSIMILE
`
`(75)
`
`Inventors: Gilbert W. Van Hoy, Broomfield;
`Charles A. Gonzales, Westminster;
`David L. Newcomb, Louisville;
`
`A.Dessel,Boulder,allofCO(US)
`(73) Assignee: Datex-Ohmeda, Inc., Louisville, CO
`(US)
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`US.C. 154(b) by 0 days.
`
`(*) Notice:
`
`(21) Appl. No.: 09/386,691
`(22)
`Filed:
`Aug. 30, 1999
`(Under 37 CFR 1.47)
`ar
`Related U.S. Application Data
`(63) Continuation-in-part of application No. 08/938,224,filed on
`Sep. 26, 1997, now abandoned.
`A61B 5/00
`Int. C17
`(51)
`cnnya. eA
`
`(52) US. Ch we . 600/323; 600/333; 128/904
`(58) Field of Search ....ccccsssssccssseseeeeeee 600/300, 301,
`600/310, 322, 323, 324, 333; 128/903,
`904
`
`(56)
`
`References Cited
`US. PATENT DOCUMENTS
`5,078,136 A
`1/1992 Stone etal.
`
`9/1994 Hollub
`5,348,004 A
`5/1996 Galen et al. oe. 128/904
`5,515,176 A *
`8/1996 Davidet al. uc. 128/904
`5,544,649 A *
`5,581,369 A * 12/1996 Righter et al. 0... 128/904
`5,701,894 A
`12/1997 Cherryetal.
`
`“te BY examine
`Primary Examiner—Eric F. Winakur
`(74) Attorney, Agent, or Firm—Marsh Fischmann &
`Breylogle LLP
`(57)
`
`ABSTRACT
`
`A photoplethysmographic monitoring system such as a pulse
`oximeter collects data regarding the blood analyte concen-
`tration and pulse rate of a patient through the analysis of
`light transmitted form an emitter through tissue to a photo
`detector. It is often necessary to review the collected data,
`such as oxygensaturation, pulse rate and pulsatility value at
`a location remote to the patient being monitored. The
`photoplethysmographic system formats the selected data for
`transmittal
`to a remote facsimile machine via standard
`telephone communication systemsusing an internalor exter-
`nal modem. The formatter is able to function within the
`rocessing
`and memorv
`constraints of
`pulse oximeters b
`formatting ad transmitting the data in sections, Formatted
`.
`:
`data may be sent via hard-wired telephone, cellular phone,
`PCSdigital telephones or through satellite communication
`systems enabling transmittal of data from a portable pho-
`toplethysmographic system.
`19 Claims, 20 Drawing Sheets
`
`
`
`3t
`
`33
`
`MAIN MEMORY
`
`PULSATILITY
`VALUE GEN
`
`PULSE
`
`$p0)
`GENERATOR
`
`GRAPH
`
`MEMORY
`BUFFER
`
`STATISTIC &
`ALARM
`GENERATOR
`
`
`ANALOG
`10
`DIGITAL
`CONVERTER
`
`GENERATOR
`
`
`
`
`
`STROBE —<1 CPU
`
`MODEM
`ANALOGISERIAL
`INTERFACE
`
`
`
`
`
`
`
`
`
`
`MODEM
`
`40
`
`SIGNAL QUALITY
`MONITOR
`
`
`
`1
`
`APPLE 1021
`
`APPLE 1021
`
`1
`
`

`

`U.S. Patent
`
`—
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`
`US 6,415,166 B1
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`US 6,415,166 B1
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`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 2 of 20
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`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 3 of 20
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`US 6,415,166 B1
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`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 4 of 20
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`US 6,415,166 B1
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`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 5 of 20
`
`US 6,415,166 B1
`
`Gols Move
`ANOHdsTALYALAWIXOa
`
`6
`
`
`
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 6 of 20
`
`US 6,415,166 B1
`
`PULSE OXIMETRY INSTAREPORT
`
`H GONZALES
`110
`DR CASEY
`
`GENERAL
`
`602
`
`BY.
`COMMENTS
`
`STUDY DURATION AND VALUES
`TIME
`PR
`01/02/99 00:00:00
`STUDY START DATETIME:
`
`
`
`STUDY END DATETIME: 01/03/89 12:00:00|LOW Sp0. 81% 134BPM 00:58:05
`AVERAGE $p0:
`"
`Sp0 STD.
`DEV.
`Bi
`
`
`
`12:0000 696
`STUDY DURATION:
`TIME
`$00)
`
`HIGH PR 100BPM—go% 02:00:00
`
`LOW PR
`61BPM
`30%
`04:58:06
`#SDO2VALUES BELOW ASH 1
`AVERAGEPR
`72. BPM
`
`AL DURATION BELOW 85% 00:13:34
`
`Sp09 PULSE OXIMETRY INSTAREPORT
`
`
`
`
`
`
`
`
`
`0-70% 71-75% 76-80% 81-85% 86-90% 91-95% 96-100%
`
`PAGE 1 OF 2
`
`FIG.6A
`
`7
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 7 of 20
`
`US 6,415,166 B1
`
`601
`
`610q-~—
`
`H GONZALES
`110
`DR CASEY
`GENERAL
`|
`
`PULSE OXIMETRY INSTAREPORT
`
`602
`
`BY
`COMMENTS
`
`LEGEND:
`
`616 ee
`LOWSp0) 617°. == NODATA
`
`
`PAGE 2 0F 2
`
`
`
`
`611
`
`
`
`
`613
`
`
`615
`
`
`611
`
`613
`
`615
`
`611
`
`
`
`
`
`
`
`0
`
`05:00:00 07:00:00 __ 06:00:00
`
`
`
`
`
`
`613
`
`615
`
`0
`08:00:00
`PULSE OXIMETRY INSTAREPORT
`
`09:00:00
`
`10:00:00
`
`14:00:00
`
`12:00:00
`
`8
`
`

`

`—|00:00:12
`
`
`LOW Sp0,
`HIGH PR
`LOW PR
`AVERAGE Sp0O
`Sp» STD.DEV
`SUMMARYSTATISTICS
`%TIME PER SpOy RANGE
`0
`20 40 60 80
`100 %
`as 67
`90-100
`85-89!
`0
`!
`80-84
`33
`i
`!
`70-79 ||
`0
`I
`Oi
`rr i tt 0
`TIME PER SpO> RANGE
`90-100%
`00:00:24
`85-80%
`00:00:00
`80-84%
`00:00:12
`70-79%
`00:00:00
`0-69%
`00:00:00
`
`||#Sp02 VALUES BELOW 85%:
`—|
`
`2T
`
`OTAL DURATION BELOW 85%:
`
`FIG.7
`
`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 8 of 20
`
`US 6,415,166 B1
`
`H GONZALES
`110
`DR CASEY
`GENERAL
`BY:
`COMMENTS:
`
`STUDY DATE:
`|_| 05/16/98
`
`ALARM LEGEND
`HIGH Sp09..ussssssnnnnneine '
`LOWSp. t
`NO SENSOR... eceseecteeens |
`SENSOROFF........-e:secsseeeeeiess ?
`6-SECOND FORMAT
`Sp05
`9 50 60 70 80 90 100 SpQ.
`!
`I
`80
`,
`95
`1
`'
`4 82
`|
`|
`|
`84 !
`|
`1
`9 86
`|
`!
`|
`|
`5 88
`90
`
`|Itt'i
`
`
`
`STUDY DURATION AND VALUES
`-—| START DATE/TIME:
`05/16/98
`12:34
`
`END DATE/TIME:
`05/16/98
`12:35
`
`[| STUDY DURATION:
`00:01:00
`
`80% 840
`90.9
`80°
`90%
`
`9
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 9 of 20
`
`US 6,415,166 B1
`
`803-4
`
`804
`
`TREND DATA OUTPUT
`6 SECONDS PER DATA POINT
`P HERNANDEZ
`93256
`JP CLAIR
`GENERAL
`09/03/98
`14:01:31
`14:01:25
`14:01:19
`14:01:13
`14:01:07
`14:01:01
`14:00:55
`14:00:49
`14:00:43
`14:00:37
`
`SpOQ2= 80
`SpO2= 81
`SpO2= 81
`SpO2= 97
`SpO2= 99
`SpO2=100
`$p02=100
`Sp02=
`SpO02=
`Sp02=
`
`Pl=1.38
`Pl=1.43
`Pl=1.48
`PI=1.56
`PI=2.14
`Pl=0.47
`Pl=
`Pl=
`PI=
`P=
`
`ee
`be
`
`END TREND DATA
`
`+»
`
`LOW Sp02
`LOW Sp02
`LOW Sp02
`
`NO SENSOR
`NO SENSOR
`NO SENSOR
`
`FIG.8
`
`10
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 10 of 20
`
`US 6,415,166 B1
`
`MODEM STATUS
`
`SELECT DATA>
`(12) SEND DATA>
`
`STATS>
`
`SETUP MODEM>
`
`SELECT HOURS
`
`12 HOURS
`
`HOUR -/+>
`(24) ALL>
`
`11
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 11 of 20
`
`US 6,415,166 B1
`
`902
`
`SEND DATA
`
`FAX>
`TO HOST SYSTEM>
`
`900
`
`900
`
`WAIT FOR CALL>
`
`-
`
`902
`
`AFTER TONES ARE
`
` DIAL FAX
`
`HEARD PRESS
`
`950
`
`a op
`
`900
`
`
`
`1210
`1220
`1Or=:
`
`FIG.12
`
`12
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 12 of 20
`
`US 6,415,166 B1
`
`SENDING DATA
`
`VLA
`
`WAIT FOR CALL...
`
`DIAL HOST SYSTEM.
`AFTER TONES ARE
`HEARD PRESS
`
`13
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 13 of 20
`
`US 6,415,166 B1
`
`1670 1620
`SUBROUTINE END MENU
`
`DATE
`
`1630
`
`START MENU
`
`DISPLAY
`MENU
`
`USER INPUTS
`MENU
`
`SELECTION
`
`1640
`
`
`1650
`No
`
`
`
`
`LABEL
`SELECTION=
`LABELS
`SUBROUTINE
`
`
`USER
`SELECTION=
`MODEM
`
`YES
`
`MODEM
`SUBROUTINE
`FIG.17
`
`1645
`
`USER\YES "609
`
`1660
`
`YES
`
`NO
`
`NO
`
`1665
`
`SETTINGS
`SUBROUTINE
`
`14
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 14 of 20
`
`US 6,415,166 B1
`
`START
`MODEM
`
`1770
`
`
`aay
`MENU
`SELECTIONS
`
`
`
`1720
`
`1730
`
`4780
`
`USER
`
`SELECTION=
`CANCEL
`9
`
`YES
`
`RETURN TO
`MENU
`
`
`
`
`
`
`
`
`USER INPUTS
`MODEM
`MENU
`SELECTION
`
`
`
`SUBROUTINE
`
` SELECT
`
`
`
`DATA
`SUBROUTINE
`FIG.18
`
`
`
`DATA
`SUBROUTINE
`FIG.19
`
`SETUP
`MODEM
`
`1745
`
`1765
`
`15
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 15 of 20
`
`US 6,415,166 B1
`
`1870
`
`START
`SELECT DATA
`
`1820
`
`
`
`DISPLAY
`DATA MENU
`
`SELECTIONS
`
`1830
`USER INPUTS
`DAT
`A
`
`SELECTION
`
`
`
`1875
`
`USER
`SELECTION=
`ETYRN
`
`
`
`Hee
`BUFFER
`
`
`1880
`
`STORE
`
`RETURN
`
`1845
`YES|DISPLAY STATS
`USER
`SELECTION=
`MESSAGE SET
`STATS
`
`STAT FLAG
`
`DISPLAY NUMBER
`OF HOURS SET
`NUMBER OF
`
`HOURS
`
`189°
`
`1865
`
`
`DISPLAY N HOURS
`SELECTED SET
`NUMBEROF
`HOURS
`
`1840
`
`
`
`16
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 16 of 20
`
`US 6,415,166 B1
`
`START
`SEND DATA
`
`SEND DATA
`
`SELECTIONS
`
`
`1920 we
`SELECTION:
`
`
`1970
`
`ANCEL
`
`1980
`
`?
`
`YES
`
`4930
`
`USER INPUTS
`DATA
`SELECTION
`
`1940
`
` AND MENU
`ONDBAT
`RETURN
`
`
`
`
`
`
`1945
`USER\.YES FAX
`
`SELECTION=
`SUBROUTINE
`FAX
`FIG.20
`
`FIG.22
`
`1955
`
`1965
`
`
`
`TO HOST
`SYSTEM
`SUBROUTINE
`FIG.21
`
`
`
`
`
`WAIT FOR
`ALL
`SUBROUTINE
`
`
`
`17
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 17 of 20
`
`US 6,415,166 B1
`
`
`
` USERCANCEL?
` SPLAY
`
`SELECTION=
`
`MESSAGE
`“ACTION NOT
`
`COMPLETE”
`
`DISPLAY
`“SENDING DATA”
`MESSAGE AND
`
`RETRIEVE DATE,
`INSERT IN FAX
`FORMAT
`
`INSER
`
`
`
`FORMATTED
`DATA TO
`
`FAX FORMAT SEND FAX
`MODEM
`
` RETRIEVE DATA
`FROM MEMORY
`
`BUFFER,
`INSERT
`IN FAX FORMAT
`SCROLL BAR
`
`
`
`18
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 18 of 20
`
`US 6,415,166 B1
`
`START TO HOST
`SYSTEM
`
`DISPLAY MESSAGE
`“DIAL HOST
`SYSTEM, AFTER
`TONES ARE HEARD
`PRESS RETURN”
`
`
`
`
`
`
`2120
`
`2130
`
`RETURN OR
`
`SUBROUTINE
`
` USER INPUTS
`CANCEL 2145
`
`USER
`SELECTION=
`
`RETRIEVE LABEL DATA
`INSERT IN ASCII FORMAT
`
`RETURN
`
`2150
`RETRIEVE DATA FROM
`MEMORY BUFFER,INSERT
`
`IN ASCII FORMAT
`
`IN ASCII FORMAT
`
`RETRIEVE DATE, INSERT
`
`DATA TO MODEM
`
`SEND ASCII FORMATTED
`
`
`
`
`DISPLAY “SENDING DATA’
`
`MESSAGEfND SCROLL
`
`19
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 19 of 20
`
`US 6,415,166 B1
`
`MESSAGEAND SCROLL
`
`YES
`
`RETRIEVE LABEL DATA
`INSERT IN ASCII FORMAT
`
`RETRIEVE DATA FROM
`MEMORYBUFFER, INSERT
`IN ASCII FORMAT
`
`RETRIEVE DATE, INSERT
`IN ASCII FORMAT
`
`SEND ASCII FORMATTED
`DATA TO MODEM
`
`2250
`
`2295
`
`2260
`
`2265
`
`DISPLAY “SENDING DATA"
`
`2270
`
`TART WAIT FOR
`CALL
`SUBROUTINE
`
`DISPLAY MESSAGE
`“WAIT FOR CALL’
`
`USER INPUTS
`CANCEL OR NO
`INPUT
`
`USER
`SELECTION=
`
`COMPLEN
`2
`
`DISPLAY
`MESSAGE
`
`“ACTION NOT
`COMPLETE”
`
`FIG.22
`
`20
`
`20
`
`

`

`U.S. Patent
`
`Jul. 2, 2002
`
`Sheet 20 of 20
`
`US 6,415,166 B1
`
`START
`PRINT
`
`
`
` 2320
`
`USER ENTERS
`
` USER
`MODE
`
`GET TIME
`INTERVAL AND
`
`SELECTION=
`REAL
`TIME
`
`USER
`SELECTION=
`TREND
`
`STOP REAL TIME
`PRINTING
`
`SELECTION
`
`
`
` STOP PRINTING
`
`MECHANISM
`
` USER
`
`SELECTION=
`STOP
`
`FORMATDATA AND
`SEND TO PRINT
`
`FIG.23
`
`21
`
`21
`
`

`

`US 6,415,166 B1
`
`1
`PHOTOPLETHYSMOGRAPHIC DEVICE
`WITH REMOTEFACSIMILE
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`
`This application is a continuation-in-part of application
`Ser. No. 08/938,224, filed on Sep. 26, 1997, and titled
`“PHOTOPLETHYSMOGRAPHIC DEVICE WITH
`REMOTE FACSIMILE”, now abandoned, which is incor-
`porated herein by reference in its entirety.
`FIELD OF THE INVENTION
`
`This invention relates to the collection and transmission
`of data in medical monitoring equipmentand, in particular,
`to the collection, selection, arrangement, formatting, and
`transmission of data in photoplethysmographic systems
`which relate to the concentrations of certain blood analyte
`levels of a patient.
`BACKGROUND OF THE INVENTION
`
`is a problem in the field of monitoring systems to
`It
`transmit photoplethysmographic monitoring data to a
`physician, hospital, or other care giver from a remote
`location using only the hardware associated with the stan-
`dard photoplethysmographic devices. To date no photopl-
`ethysmographic monitors exist which are capable of pre-
`formatting the data collected and blood analyte
`measurements generated by a photoplethysmographic moni-
`tor.
`
`A facsimile is a digital representation of an image. Data
`and text in a facsimile is not stored as words and letters in
`ASCII format, but rather the imageof the text, data, graphs,
`etc. 1s stored as a gray-scale bit map. It
`is possible to
`purchase a standard modem for the transmittal of data to a
`remote location. However,
`there is no way to send the
`information directly to a facsimile machine due to the
`special facsimile data format which is required.
`The problemsassociated with the limitations of standard
`photoplethysmographic systemshas led to a numberofprior
`art alternatives which have their own limitations and draw-
`backs.
`
`The Medical Data Archiving Corporation (MDAC)
`Oximetry Recording & Reporting System (OxiScan™)pro-
`vides a method and system for transmission of oximetry data
`via standard telephonelines. The OxiScan™ system requires
`the connection of the photoplethysmographic monitor to a
`processing terminal. Additionally, the output of the process-
`ing terminal is not sent to the ultimate care provider, but
`rather, is directed to the MDAC Reporting Service which
`then sends an oximetry report to a facsimile machine within
`fifteen minutes. The delay caused by the intermediate pro-
`cessing at a second remote location and the possibility of
`error introduced by the additional transmission step reduces
`the usefulness of such a system.
`In most commercial pulse oximeters such as the Ohm-
`eda® 3800 or the Nellcor -3000 there is an RS232 serial
`port which maybe used to download collected photoplethys-
`mographic data from a pulse oximeter to another computing
`device. However,
`there is presently no photoplethysmo-
`graphic system that enables a user, such as a remote acute
`care provider,
`to convey photoplethysmographic data
`directly from the remote field location to the ultimate care
`provider in the hospital or physician’s office.
`SUMMARYOF THE INVENTION
`
`The above described problemsare solved and a technical
`advance achievedin the field by the photoplethysmographic
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`system of the present invention which conveys photopl-
`ethysmographic data to the standard facsimile machine of a
`remote user in a simple, direct, and immediate manner. This
`photoplethysmographic system produces a facsimile data
`format serial output which can be transmitted to the remote
`facsimile via telephone lines via an external modem or via
`a modem internal to the photoplethysmographic monitor.
`Photoplethysmographic data may also be transmitted to a
`remote host system via the internal or external modem. The
`remote host system may also retrieve the data through
`contacting the system of the present
`invention directly.
`Lastly, through an internal printer, photoplethysmographic
`data may be printed out in hard copy form.
`In a preferred embodiment of the invention, a photopl-
`ethysmographic monitoring system provides the facsimile
`data format for oximetry data to an external modem viaits
`serial port. In another embodiment of the invention, the
`photoplethysmographic monitor contains the modem inter-
`nally and, therefore, can transmit formatted reports directly
`to the facsimile machine of a remote user without additional
`hardware.
`
`DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a functional block diagram of one embodiment
`of the present
`invention in which the formatted data is
`directed to an external modem orto an internal printer.
`FIG. 2 is a block diagram of the embodiment of FIG. 1
`further depicting functional components of the system of
`FIG. 1.
`
`FIG. 3 is a block diagram of the embodiment of FIG. 1
`further depicting alternative functional components of the
`system of FIG. 1.
`FIG. 4 is a functional block diagram of an alternative
`embodimentof the present invention in which the modem is
`internal to the photoplethysmographic device.
`FIG. 5 is a block diagram of the alternative embodiment
`of FIG. 4 further depicting functional components of the
`system of FIG. 4.
`FIGS. 6A and 6B depict the facsimile report format of a
`device according to an embodimentof the present invention.
`FIG. 7 depicts the internal printer report format of a
`device according to an embodimentof the present invention.
`FIG. 8 depicts the remote host system report format of a
`device according to an embodimentof the present invention.
`FIGS. 9 through 15 depict various user interface screens
`provided in an embodiment of the present invention.
`FIGS. 16 through 23 depict a series of software flow
`diagrams for one embodimentof the present invention.
`
`DETAILED DESCRIPTION
`
`The data collected by a pulse oximeter, which is a type of
`photoplethysmographic monitoring system, is used to gen-
`erate a saturation value for oxygenated hemoglobin (SpO.,)
`which is directly related to the oxygen content of the
`patient’s blood, a pulse rate, and a pulsatility value. Other
`types of photoplethysmographic monitors may include
`blood analyte concentrations for carboxyhemoglobin,
`methemoglobin, or other blood analytes.
`In most pulse
`oximeters a number representing the oxygen content of the
`blood of a patient (SpO.) is displayed. A photoplethysmo-
`graphic waveform ofthe pulsatile variations in the collected
`data over time or trend data over a period of time may also
`be displayed. The pulse of the patient may also be displayed,
`and in certain Ohmeda® pulse oximeters, a Perfusion Index
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`US 6,415,166 B1
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`3
`PI™ pulsatility value is displayed. The PI™ pulsatility value
`indicates a quantified level of perfusion of the tissue of a
`patient through the inflow of blood intothe tissue. All of this
`information is useful to the medical practitioner in deter-
`mining the condition and proper treatment of a patient.
`The present invention enables the user of a photoplethys-
`mographic system to send collected photoplethysmographic
`data from the system to a remotely located facsimile
`machine thereby providing a formatted hard copyprintout of
`the photoplethysmographic data without the use of auxiliary
`computing devices, such as a personal computer or central
`monitoring station. Thereby, useful photoplethysmographic
`data, such as SpO, levels, pulse rates, and pulsatility values
`can be transmitted in a useful format from any location to
`a remotely located medical practitioner using standard
`telecommunications equipment. Data mayalso be sent
`directly to a remote host system, such as a personal
`computer, through
`the modem, or directly downloaded to a personal com-
`puter through an RS232 interface.
`In addition,
`the
`present invention will automatically answer an incom-
`ing call from a personal computer, and allow the
`personal computer to access the photoplethysmo-
`graphic data. An optional internal printer can provide
`on-demand hard copy output of the collected data.
`The monitoring apparatus described herein as the pre-
`ferred embodiment is a pulse oximeter instrument which
`measures the oxygen saturation of the arterial blood of a
`patient. The pulse oximeter instrument operates by illumi-
`nating the arteriolar bed of a perfused appendage, ear lobe,
`or nasal septum of the patient with light from light sources
`characterized by spectra having distinct center wavelengths.
`The center wavelengthsare selected so that the light emitted
`by one light source is highly absorbed by oxygenated
`hemoglobin contained in the arterial blood, while the other
`is selected with respect to its absorbency by deoxygenated
`hemoglobin. The pulse oximeter instrument then measures
`the magnitude of the light that passes through the illumi-
`nated tissue. The pulsatile component of the light output
`from the tissue is used to determine the oxygen saturation of
`the arterial blood flow.
`Referring to FIGS. 1 and 2, a probe 20 containing a
`plurality of light sources 9 and 10, such as LED orlaser
`diodes, and a photo detector 7 is attached to an appendage
`of the patient, such as a finger 8. The appendageis rich in
`arterial blood flow so that the light transmissivity of the
`arterial blood, and thereby the oxygen saturation thereof, can
`be directly measured. The light sources 9 and 10 and photo
`detector 7 may, alternatively, be placed on the ear lobe or
`nasal septum of the patient. The output signal produced by
`the photo detector 7 is transmitted via cable 6 and is
`processed by the pulse oximeter instrument 30, producing a
`numeric value indicative of the oxygen saturation of the
`arterial blood. It is a collection of these oxygen saturation
`levels (SpO., levels) overtime that is transmitted to a remote
`location or retrieved from a remote location or printed out on
`an internal printer.
`The functional block diagram of the pulse oximeter
`instrument 30 of FIG. 1 provides a description of the internal
`processing necessary to provide a complete facsimile data
`format output to modem 40 and to remote facsimile 70, to
`provide an ASCII data format output to modem 40 and to
`remote host system 80, and to provide an ASCII data format
`output to print mechanism 23.
`Raw input data from probe 20 is converted to a digital
`representation by analog-to-digital converter 37. The digital
`data set representing the output from photo detector 7 of
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`probe 20 is then used by the software internal to the pulse
`oximeter instrument 30 to calculate the SpO, level of the
`patient’s blood in a well known way. For instance,
`the
`techniques discussed in U.S. Pat. No. 5,503,148 issued to
`Pologe et. al., hereby incorporated by reference, may be
`used for calculating SpO, levels.
`The digital data set from the analog-to-digital converter
`37 is used by the SpO, generator 34 to generate SpO,
`saturation levels at specific time intervals of at least every
`six seconds. The SpO, saturation levels generated by the
`SpO, generator 34 are then forwarded to a memory buffer 32
`where a time-tagged series of SpO, blood saturation values
`is stored for later output to central processing unit 21 and on
`to main memory 36, modem analog/serial
`interface 25,
`output display 27, and printer parallel interface 22, and for
`use by graph generator 33 andstatistic and alarm generator
`35. Output display 27 is typically a combination of an LED
`display and an LCD display, but could be one or the other
`only. Photoplethysmographic waveform and trend data are
`easily displayed on the LCD type display. Saturation and
`pulse rate values and alarm indicators are readily displayed
`on the LED type display.
`The SpO, saturation levels generated by the SpO, gen-
`erator 34 are forwarded from memory buffer 32 to a statistic
`and alarm generator 35 where a set of statistical character-
`istics for a data set are defined for the buffered set of data.
`
`For example, a histogram may be generated as well as a
`breakdown by range of the amount of time the SpO, level
`was within certain ranges. Other statistical characteristics
`such as the highest and lowest SpO, levels and durations for
`each of the high and low levels for a given set of data can
`also be generated by the statistic and alarm generator 35.
`Examples of alarms which can be generated bythe statistic
`and alarm generator 35 include “Low SpO,”, “High SpO,”,
`“No Sensor” and “Sensor Off’ warnings. These latter two
`warnings are generated by the data emerging from the signal
`quality monitor 38.
`Signal quality monitor 38 receives data from the analog-
`to-digital converter which is indicative of the quality of the
`input data signal. The quality of the signal can be a measure
`of the signal to noise ratio, intensity and/or frequency of
`motion artifacts, or other measure of the credibility of the
`input data, regardless of the signal strength. The signal
`quality monitor 38, in response to the received data, pro-
`duces one of a plurality of drive signals to generate an
`indication of the quality of the input data signal in order to
`determine if an alarm such as “No Sensor”or “Sensor Off”
`
`should be displayed to the user.
`There are other characteristics of the input signal received
`from probe 20 that are of interest to the user of the pulse
`oximeter 30, such as the patients’ pulse rate and pulsatility
`value. Data from analog-to-digital converter 37 is also
`supplied to pulse strobe 39 to provide a time-tagged pulse
`value for the patient which is then stored in memory buffer
`32 for later transfer through central processing unit 21 to
`specific memory locations in main memory 36. The data will
`later be used by modem analog/serial
`interface 25 and
`printer parallel interface 22. The statistic and alarm genera-
`tor 35 also uses the set of pulse values to develop a high and
`low pulse statistic and rate duration as well as high and low
`pulse alarms. Data from analog-to-digital converter 37 is
`also forwarded to a pulsatility value generator 31 where the
`pulsatility value is generated according to one or more
`known methods,including,but not limited to, percent modu-
`lation.
`Graph generator 33 provides a bar graph or other graphi-
`cal representation of photoplethysmographic data which can
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`US 6,415,166 B1
`
`5
`then be stored in main memory 36 and formatted for
`transmission to the remote facsimile via modem 40. Internal
`
`clock 26 is used to time-tag data and provide the date of data
`collection,
`the time the data collection began, and the
`duration of the data collection.
`
`the user,
`input 15 provides a mechanism for
`User
`generally, the nurse, home-care aide or physician, to input
`data regarding the patient and the time and date of the
`photoplethysmographic study. Additionally, user input 15
`permits the user to select the duration of the study, to select
`the format of data to be displayed on output display 27, to
`select modem characteristics, and set up pulse oximeter 30
`for transmission of data via modem 40 or in response to
`receiving a call from remote host system 80. User input 15
`may comprise one or more of the following input devices:
`touch-sensitive screen, keyboard,
`touch-pad, mouse,
`trackball, joystick, or axially actuatable rotary dial (for
`example, as disclosed in U.S. Pat. No. 5,627,531 to Reichert
`et al., and hereby incorporated by reference). In an alternate
`embodimentthe user input 15 is external to pulse oximeter
`30 and communicates through the standard RS232 port
`found on most pulse oximeters. In this alternate embodiment
`user input 15 may be a personal computer or some other
`communication device having a user interface and a serial
`communication port.
`Print mechanism 23 can provide on-demand hard copy
`output of the data collected by probe 20 and processed by
`pulse oximeter 30. Printer mechanism 23 is typically a
`thermal single column dot matrix printer. Printer user input
`24 is only active when waveform data or trend data is being
`displayed on output display 27.
`The user may select one of several options with printer
`user input 24. The user mayselect to print out real time data
`while monitoring the patient. The real time data may be
`printed out in SpO, format or PI™ format in either six
`second or thirty second intervals. Selecting a summation
`option during real time printing immediately stops the real
`time printing. Summary statistics are then printed out
`encompassing all the data that was printed out in real time
`up to the time when the summation option was selected. The
`user may also choose to print trend data over a selected
`period of time. The user can further select to print all the
`trend data over the selected period of time or only summary
`statistics for the selected period of time.
`FIG. 2 depicts a system according to the present invention
`wherein probe 20 is connected to pulse oximeter 30. Upon
`selection of a send fax option, pulse oximeter 30 generates
`data in a facsimile data format which is sent via modem 40
`and telephone 50 through a standard telephone jack 60
`through the telecommunication switching network of local
`and/or long distance carriers to remote facsimile 70. Upon
`selection of a send to host system option, pulse oximeter 30
`generates data in an ASCII data format which is sent via
`modem 40 and telephone 50 through a standard telephone
`jack 60 through the telecommunication switching network
`of local and/or long distance carriers to remote host system
`80. Uponselection of a wait for call option, pulse oximeter
`30, when called by remote host system 80, generates data in
`an ASCII data format which is sent via modem 40 and
`
`telephone 50 through a standard telephone jack 60 through
`the telecommunication switching network of local and/or
`long distance carriers to remote host system 80.
`FIG. 3 depicts an additional connection scheme where
`external modem 40 is compatible with cellular communica-
`tion devices for transmission of the data in facsimile data
`format
`to remote facsimile 70 or ASCII data format to
`
`remote host system 80.
`
`It
`
`is also possible to use other
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`telecommunications devices, such as digital PCS
`telephones, or satellite telephony services such as Global-
`star® or Iridium®. Such systemsallow the pulse oximeter to
`be used as a portable unit with the ability to provide
`facsimile data format output or ASCII data format output to
`any remote facsimile machine independent of hard-wired
`connections to existing telephone systems.
`FIG. 4 depicts an alternate embodimentof a pulse oxime-
`ter according to the present invention. Probe 20 is connected
`to pulse oximeter 130 which contains essentially identical
`circuitry and software to the above discussed embodimentof
`FIG. 1 including user input 115, central processing unit 121,
`printer interface 122, print mechanism 123, printer user
`input 124, modem analog/serial interface 125, internal clock
`126, output display 127, pulsatility value generator 131,
`memory buffer 132, graph generator 133, SpO, generator
`134, statistic and alarm generator 135, main memory 136,
`analog-to-digital converter 137, signal quality monitor 138,
`and pulse strobe 139. In this alternate embodiment, however,
`modem 140 is internal
`to pulse oximeter 130,
`thereby
`reducing the number of external boxes and connections
`required for use of the remote facsimile function.
`FIG. 5 is a block diagram of the alternative embodiment
`of FIG. 4 further depicting functional components of the
`system of FIG. 4. Referring now to FIG. 5, pulse oximeter
`130 with an internal modem is connected to the remote
`
`facsimile 70 or the remote host system 80 via telephone 50
`and telephone jack 60.
`FIGS. 6A and 6B depict one embodiment of a facsimile
`report format for photoplethysmographic data for a device
`according to the present invention. Referring now to FIGS.
`6A and 6B, Label Information Field 601 provides up to four
`lines of alphanumeric text, such as patient name, patient
`number, doctor name, and hospital. By And Comments Field
`602 provides up to four lines of alphanumeric text, such as
`clinician name and any relevant comments. Data for Label
`Information Field 601 and By And Comments Field 602 is
`entered either through user input 15 which is internal to
`pulse oximeter 30, or through a personal computer keyboard
`which is in serial communication with pulse oximeter 30.
`Study Start Time Field 603, Study End Time Field 604,
`and Study Duration Field 605 provide the date and time the
`data collection began, the date and time the data collection
`ended, and the duration of the data collection respectively.
`These values are derived from the internal clock 26 of pulse
`oximeter 30, which is also used to time-tag data.
`Statistic and alarm generator 35 is responsible for gener-
`ating the data found in Study Highlights Field 606, which
`includes the lowest SpO, value for the data printed with a
`corresponding Pulse Rate (PR) and time stamp. The average
`SpO, value, the SpO. standard deviation, the high PR rate
`with corresponding SpO,value and time stamp, the low PR
`rate with corresponding SpO. value and time stamp, and
`average PR are also reported. The standard deviation rep-
`resents the scatter of the SpO. data points. A high standard
`deviation represents a wide range of SpO,values.
`SpO, Values Below Field 607 showsthe total numberof
`SpO,values below the low SpO, alarm limit. Total Duration
`Below Field 608 showsthe total amountof time for all SpO.,,
`values below the low SpO, alarm limit. The data for these
`fields is forwarded bythe statistic and alarm generator 35 to
`the modem analog/serial interface 25 which then places the
`data in the correctfields.
`
`Percent Time Per SpO. Range Block 609 contains a graph
`of the percentage of time the patient’s SpO., was recorded in
`each of the ranges indicated. This graph is generated by
`graph generator 33 using data from memory buffer 32.
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`US 6,415,166 B1
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`7
`Alarm Legend 610 provides a legend of trend events that
`may occur. An event’s legend symbol appears on the report
`at the time of occurrence. Low SpO, Symbol 616 indicates
`an SpO,value was recorded that was below the low alarm
`limit. No Data Symbol 617 indicates that no data was
`recorded.
`SpO, Scale 611 indicates the percent scale for SpO,
`values displayed in the SpO, Time Graph 612. PR Range
`613 indicates the beats per minute range used for PR values
`displayed in the PR Time Graph 614. Time Scale 615 shows
`the time scale used for SpO, Time Graph 612 and PR Time
`Graph 614. These graphs are also generated by graph
`generator 33 using data from memorybuffer 32.
`The modem analog/serial interface 25 of FIG. 1 sends the
`final data in the facsimile data format to remote facsimile 70
`where it appears on paper in the facsimile report format of
`FIGS. 6A and 6B. The data format and protocol for trans-
`missions to facsimile machines of the present invention are
`governed by standards established by the International Tele-
`graph and Telephone Consultative Committee (CCITT).
`Telephone system standards for