US005673692A
`
`[11]
`
`145]
`
`Patent Number:
`
`Date of Patent:
`
`5,673,692
`Oct. 7, 1997
`
`OTHER PUBLICATIONS
`
`United States Patent
`Schuizeet al.
`
`[54]
`
`SINGLE SITE, MULTI-VARIABLE PATIENT
`MONITOR
`
`[75}
`
`Inventors: Arthur E. Schulze, Houston; Tommy
`G. Cooper, Friendswood, both of Tex.
`
`[73] Assignee: BioSignals Ltd. Co., Albuquerque, N.
`Mex.
`
`[21] Appl. No.: 383,116
`
`[22] Filed:
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`T. Shinozaki, MD,et al, “Infrared Tympanic Thermometer:
`Evaluation of A New Clinical Thermometer”, Critical Care
`Medicine, 1988, vol. 16, No. 2., pp. 148-150.
`R. C. Cork, MD PhD,et al, “Precision And Accuracy of
`Intraoperative Temperature Monitoring”, ANESTH ANAGL,
`1983, vol. 62, pp. 211-214.
`J. J. Nobel, MD, “Infrared Ear Thermonetry”, Pediatric
`Emergency Care, Feb. 1992, vol. 8, No. 1, pp. 54-58.
`J. Vandeput, MD,et al “Photoelectric Plethysmography In
`Monitoring Skin Circulation”, Southern Medical Journal,
`Feb. 3, 1995
`May 1990, vol. 83, No. 5, pp. 533-537.
`
`[52] Tint, C02nncccecssscsssssssssssscesecerssetesnssneecesens A61B 5/00
`
`Y. Mendelson, PhD, et al, “Noninvasive Measurement Of
`[52] U.S. Che cc ceccesscseenssees 128/633; 128/664; 128/666;
`Arterial Oxyhemoglobin Saturation With A Heated And A
`.
`128/736; 356/41
`Non-heated Skin Reflectance Pulse Oximeter Sensor”, Bio-
`medical Instrumentation & Technology, Nov./Dec. 1991, pp.
`[58] Field of Search .........ccscssssscsscssseeseanes 128/670, 664,
`472-480.
`128/736, 691, 689, 665, 633, 634, 666
`S. Schotz, MD,et al, “The Ear Oximeter As A Circulatory
`Monitor”, Anesthesiology, May—Jun. 1958, vol. 19, No. 3,
`pp. 386-393.
`Primary Examiner—Robert Nasser
`3,858,574—1/N97TS Page ....scsssesessncccrsoeessenseartacesees 128/205
`Attorney, Agent, or Firm—Norman E. Brunell
`3,910,257 10/1975 Fletcheret al.
`wenee 128/670
`[57]
`ABSTRACT
`4,797,840
`1/1989 Fraden ............
`364/557
`5,109,849
`5/1992 Goodman et al.
`.......sesreeree 128/670
`5,115,133
`5/1992 Knudson...............
`250/341
`5,137,023
`8/1992 Mendelson etal
`128/633
`5,152,296 10/1992 Simons ........0000
`128/670
`5,167,235 12/1992 Seacord
`128/664
`5,213,099
`5/1993 Fripp, Jr
`128/633
`5,297,554
`3/1994 Glynn etal
`128/665
`5,361,758 11/1994 Hall et al
`128/633
`5,469,855
`11/1995 Pompei et al
`. 128/664
`5,509,422
`4/1996 Pukamii ou...scccsssscessssccesssesees 128/670
`
`
`
`FOREIGN PATENT DOCUMENTS
`
`2653959A1
`3910749A1
`
`6/1978 Germany.
`4/1989 Germany .
`
`An apparatus for monitoring multiple physiological vari-
`ables of a patient at a single site on the patient can be used
`to facilitate assessment of the patient’s well being during
`medical surgery as well as during ambulatory monitoring,
`home monitoring, procedure monitoring and similar situa-
`tions. The apparatus has an infrared (IR) temperature sensor,
`a pulse oximeter sensor and a communication circuit for
`outputting information produced from the pulse oximeter
`and information produced from the infrared temperature
`measuring device. These elements are integrally placed
`within a mold or plug madeto fit the ear of the patient.
`
`8 Claims, 6 Drawing Sheets
`
`
`
`SeLLLLLLLL
`
`0001
`
`Apple Inc.
`APL1057
`U.S. Patent No. 8,652,040
`
`Apple Inc.
`APL1057
`U.S. Patent No. 8,652,040
`
`0001
`
`

`

`US. Patent
`
`Oct. 7, 1997
`
`Sheet 1 of 6
`
`5,673,692
`
`FIG.
`
`7
`
`
`CONTROLLER
`
`RECEIVER
`
`L
`
`FIG. 4
`
`C5
`
`7
`
`0002
`
`0002
`
`

`

`U.S. Patent
`
`Oct. 7, 1997
`
`Sheet 2 of 6
`
`5,673,692
`
`TWNYFLXF
`
`YOSSIIONd
`
`NOLLYOINNWNOD
`
`AXLINIUD
`
`0003
`
`
`
`LHOIT{Sed
`
`FINOS
`
`
`
`LH?GNODIS
`
`JINOS
`
`me
`
`0¢
`
`JINVAWAL
`
`JINVUEWIN
`
`0003
`
`
`
`
`
`

`

`US. Patent
`
`Oct. 7, 1997
`
`5,673,692 FIG. 3
`
`Sheet 3 of 6
`
`0004
`
`0004
`
`

`

`Sheet 4 of 6
`
`5,673,692
`
`US. Patent
`
`Oct. 7, 1997
`
`86
`
`0005
`
`0005
`
`

`

`US. Patent
`
`Oct. 7, 1997
`
`Sheet5 of 6
`
`5,673,692
`
`76
`y
`
`|
`
`FIG.
`
`10
`
`
`Seen
`LILLLLAMLELLLL
`
`_,RASAASSSAASSSALZLLLLLLLLAAA
`
`
`
`
`
`
`td
`
`150
`
`NN]
`
`0006
`
`0006
`
`

`

`U.S. Patent
`
`
`
`Oct. 7, 1997
`
`Sheet 6 of 6
`
`5,673,692
`
`eXREELSNSARSOS
`
`2.
`
`0007
`
`0007
`
`
`

`

`5,673,692
`
`1
`SINGLE SITE, MULTI-VARIABLE PATIENT
`MONITOR
`
`TECHNICAL FIELD OF THE INVENTION
`
`The present invention is related in general to monitoring
`physiological variables of a patient and in particular to a
`device for remotely monitoring multiple physiological vari-
`ables from a single site on the body of a patient.
`
`BACKGROUND OF THE INVENTION
`
`Continuous monitoring ofphysiological variables, such as
`body core temperature, is importantin patient care, particu-
`larly during surgery. However, presently known methods of
`continuously monitoring physiological variables have been
`found to be quite unsatisfactory.
`For example, methods such as monitoring a patient’s
`temperature through rectal probes or by inserting a ther-
`mistor or thermocouple against a tympanic membrane/ear
`canal are not well liked by either patients or care givers.
`On the other hand, less intrusive methods such as moni-
`toring body temperature through skin measurements can
`only provide rough indicators ofchangesin the temperature
`of a patient. Furthermore, rather than measuring body core
`temperature directly, these methods can only provide a
`rough approximation thereof. Moreover, skin temperature
`measurements are susceptible to environmental changes
`such as body movement and changes in surrounding
`temperature, light, air currents, and the like.
`SUMMARY OF THE INVENTION
`
`Thepresent invention provides, in a first aspect, apparatus
`for monitoring multiple physiological variables of a patient
`at a single site on the body of the patient.
`In one aspect, the present invention provides a single
`probe with an infrared (IR) temperature sensor, a pulse
`oximeter sensor, and a communicationcircuit for outputting
`information generated by the pulse oximeter sensor and the
`IR temperature sensor.
`In another aspect, the present invention provides a moni-
`toring system having at least two sensors for measuring
`different physiological variables of a patient in the ear canal
`of the patient including measurements of the ear canal itself
`as well as measurements of the tympanic membrane, a
`communication circuit coupled to the sensors for commu-
`nicating outputs of the sensors to an external processor, a
`battery for supplying power to the sensors and the commu-
`nication circuit, and a support for coupling the apparatus to
`the ear canal. The monitoring system also includes an
`external processor receiving outputs of the sensors from the
`communication circuit for processing the outputs of the
`sensors into physiological data.
`In still another aspect, the present invention provides a
`method for monitoring multiple physiological variables of a
`patient. The method includes the steps of measuring at least
`two different physiological variables of the patient from the
`ear canal by coupling at least two sensors to the tympanic
`membrane and ear canal, communicating outputs of the
`sensors to an external processor, and processing the outputs
`of the sensors at the external processor into physiological
`data.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`In still another aspect, the present invention provides a
`method for monitoring multiple physiological variables of a
`patient. The method includes the steps of measuringat least
`two different physiological variables of the patient from an
`
`65
`
`2
`ear by coupling at least two sensors to the ear, communi-
`catingoutputs of the sensors to an external processor, and
`processing the outputs of the sensorsat the external proces-
`sor into physiological data.
`In yet another aspect, the present invention provides an
`apparatus for monitoring multiple physiologicalvariables of
`a patient, including a housing to fit in the ear canal of a
`patient. The housing has an inner end, an outer end, an
`elongated hollow section between the ends, and a pair of
`openings through the wall of the hollow section. One or
`moreradiation sources is mounted along oneof the openings
`to emit radiation toward the lining of the ear canal of the
`patient; and a radiation sensor is mounted along the other
`opening to receive radiation from the source following
`reflection and or conduction by the lining of the ear canal.
`An additional radiation sensor is also mounted on the
`housing to receive radiation from the tympanic membrane of
`the patient.
`A substrate, which carries the radiation sources, is dis-
`posed along the housing opening for the source. Similarly,
`another substrate, which carries the companion radiation
`sensorto the radiation source, is disposed along the housing
`opening for that sensor.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a block diagram depicting a system for moni-
`toring multiple physiological variables at a single site on the
`body of a patient.
`FIG. 2 is a block diagram of a system whereby physi-
`ological variables including core temperature, heart rate and
`oxygen saturation monitored at a single site on the body of
`a patient.
`FIG. 3 depicts how the core temperature, heart rate and
`oxygen saturation are monitored from the ear by the system
`shown in FIG.2.
`
`FIG.4 depicts a monitoring system where the sensors are
`clamped to an ear bya clip.
`FIG.5 depicts a monitoring system wherein physiological
`variables are measured by measuring optical radiation trans-
`mitted through an ear lobe.
`FIG.6 is a top plan view of a housing for sources, a sensor
`and a detector such as those represented in FIG.2, but with
`the sources and sensor using the ear canal lining, while the
`detector uses the tympanic membrane.
`FIG.7 is a cross-sectional view taken along the line 7—7
`of FIG.6.
`
`FIG. 8 is an end view of the housing of FIG. 6
`FIG. 9 is a cross-sectional view taken along the line 9—9
`of FIG.8.
`FIG. 10 is the same view as FIG. 9 but with the sources,
`sensor and detector mounted in the housing.
`.
`FIG.11 is a top planar view of housing 76illustrating the
`range of angular separations for radiation sources 110 and
`radiation detector 113.
`FIG. 12 is a cross sectional view of ear muff 138 which
`supports and positions integrated electronics package 142 in
`the auditory canal.
`FIG. 13 is a cross sectional view and enlargement of
`transmitter package 134 shown in FIG. 12.
`DETAILED DESCRIPTION
`
`FIG. 1 is a block diagram of a system 2 for monitoring
`multiple physiological variables of a patient at a single site
`on the body of the patient, preferably the ear. The system 2
`
`0008
`
`0008
`
`

`

`5,673,692
`
`3
`has an apparatus 4 having at least a first sensor 6 and a
`second sensor8 affixed to a support 10, such as an ear muff
`or a plug, for holding the first and second sensors 6 and 8 at
`one ear of the patient.
`Eachofthe first and second sensors 6 and § measures one
`
`or more physiological variables of the patient under control
`of a controller 12. Controller 12 also operates to preprocess
`the output signals from the sensors 6 and 8 into data which
`is communicated to a receiver 14. The receiver 14 can be a
`human operator. The receiver 14 can also be an external
`processor which further processes the data into required
`physiological information.
`Communication can be performed by either wireless
`transmission (e.g.. by infrared signals or by radio frequency
`signals) or by wired transmission (e.g., multi-channel cable,
`fiber optic medium or multiplexed transmission).
`FIG. 2 is a block diagram depicting a monitor system 20
`wherein the present invention is embodied. The monitor
`system 20 has a circuit 22 which operates to measure
`physiological variables of a patient. The monitor system 20
`also has an external processor 24 which operates to process
`data obtained by the circuit 22.
`In operation, circuit 22 is coupled to a site on the body of
`the patient. The ear is chosen as such a site because the
`tympanic membrane provides a reliable indication of the
`patient’ s body core temperature. The lack of pigmentation in
`the tympanic membrane also makes calibration factors more
`constant across age and race of the patients. Moreover, the
`ear can be accessed more conveniently during most routine
`medical procedures, including surgery. The ear is also ther-
`mally isolated from room environment, and is largely insen-
`sitive to vasoconstriction and vasodilation because arterial
`flow through the carotid artery, which supplies blood to the
`tympanic membrane,
`is usually maintained even during
`shock.
`
`Circuit 22 has an infrared (IR) temperature sensor 26 for
`measuring body core temperature of the patient. A ther-
`mistor may also be used as temperature sensor 26 if posi-
`tioned in contact with the body. IR temperature sensor 26 is
`aimed at the tympanic membrane and outputs a signal in
`response to the temperature of the tympanic membrane. The
`output signal is sent to an IR temperature preprocessor 28,
`which has amplifiers and compensation devices for condi-
`tioning the signal for transmission.
`The output of preprocessor 28 is then communicated to
`the external processor 24 for further processing. Using the
`external processor 24 to further process the data ensures that
`there is minimal loss of data through preprocessing and that
`data processing algorithms are not restricted by the lack of
`electrical power to the sensors and or a lack of space in the
`support.
`Communication between the circuit 22 and the external
`processor 24 is performed by a communication circuit 39,
`such as a radio frequency transmitter or an infrared trans-
`mitter. Communication between the circuit 22 and the exter-
`nal processor 24 can also be performed through a mullti-
`channel cable, a fiber optic channel or multiplexed cable
`transmission, and/or through a local area network (LAN).
`In one embodiment of the present invention, communi-
`cation between the circuit 22 and the external processor 24
`is unidirectional and includes only data from the circuit 22
`to the external processor 24. In an enhanced embodiment,
`communication between the circuit 22 and the external
`processor 24 is bi-directional and includes data sent from the
`circuit 22 to the external processor 24, as well as control
`signals sent from the external processor 24 to the circuit 22
`
`4
`to selectively set such parameters as the rate of sampling
`and/or the gains of the circuit 22.
`Circuit 22 also has a pulse oximetry sensor (POS) for
`measuring oxygen saturation and heart rate of the patient.
`The POSincludesa first radiation source 34 such asa light
`emitting diode (LED), a second radiation source 36 and a
`photosensor 32, each of which operates under the control of
`a POSpreprocessor 38.
`With reference to FIG. 3, the IR temperature sensor 26,
`the first and second radiation sources 34 and 36, and the
`photosensor 32 can be placed in a plug 56 for insertion into
`the auditory canal, and aimed at the tympanic membrane 52
`but without touching it. The preprocessors 28 and 38 and the
`communication circuit 30 can be placed outside of the plug
`56 and supported by an ear muff 54.
`In other implementations, the first and second radiation
`sources 34 and 36 can be aimed at the tissue lining the ear
`canal. They can be placed outside of the auditory canal. The
`optical radiation from thefirst and second radiation sources
`34 and 36 can be directed by optical fibers into the auditory
`ear canal and aimed at the tympanic membrane 52. Under
`such implementation, the first and second radiation sources
`34 and 36, along with other components of the circuit 22,
`can be supported by an ear muff.
`Pulse oximetry data is obtained using a conventional
`technique by havingthe first and second radiation sources 34
`and 36 projecting optical radiation with different wave-
`lengths to the inner surface of the auditory canal or the
`tympanic membrane 52. The POS preprocessor 38 operates
`to activate and deactivate the first and second radiation
`sources 34 and 36 repetitively at a predetermined frequency
`(say, 75 Hz). Optical radiation from the first and second
`radiation sources 34 and 36 is absorbed by hemoglobin and
`oxygen-enriched hemoglobin differently depending on the
`wavelengths of the optical radiation. Optical radiation
`reflected by the tissue in the lining of the canal or tympanic
`membrane 52 is detected. by the photosensor 32. The pho-
`tosensor 32 converts the reflected optical radiation into
`electrical signals which are sent to the POS preprocessor 38.
`The POS preprocessor 38 processes the signals 32 into a
`form acceptable to the communication circuit 30. The com-
`Munication circuit 30 communicates the digital data to the
`external processor 24 for further processing.
`The external processor 24 can be programmed to convert
`the output from the circuit 22 to provide oxygen saturation
`of the arterial blood, based upon thedifference in absorption
`of optical radiation by hemoglobin and oxygen-enriched
`hemoglobin at different wavelengths.
`The external processor 24 can also be programmed to
`convert the output for the circuit 22 to provide heart rate
`information of the patient. Heart rate is determined from
`changes in blood volume caused by pulsatile blood flow
`associated with the arterial pulse. The changes in the blood
`volume affect the amount of optical radiation transmitted
`through the tympanic membrane 52 and the amount of
`optical radiation reflected from the tympanic membrane 52.
`Heart rate can then be computed by measuring the time
`between peaks of the electrical signal generated by the
`photosensor 32.
`The external processor 24 can be optionally programmed
`to measure respiration rate of a patient. Regular respiration
`can usually be recognized by small cyclical variations in
`heart rate (or in the amplitude of an electrocardiogram).
`Respiration rate is especially measurable under this method.
`in those patients, such as artificially ventilated patients (e.g.,
`those undergoing anesthesia), or patients with pronounced
`
`20
`
`35
`
`45
`
`50
`
`55
`
`65
`
`0009
`
`0009
`
`

`

`5,673,692
`
`5
`sinus arrhythmia for whom respiration rate is reflected by
`variations in the beat-to-beat rhythm of the heart.
`Algorithms, such as logarithmic amplification of the mea-
`sured data, can be implemented in the external processor 24
`to facilitate measurement of respiration rate and to increase
`the population of patients for whom respiration rate can be
`measured by this technique.
`The IR temperature sensor 26, the first and second radia-
`tion sources 34 and 36 may be aimed away from the
`tympanic membraneto prevent thermal interference with the
`JR temperature sensor 26 during long term monitoring.
`Thermal interference can also be reduced by measuring
`the output from the IR temperature sensor 26 during a period
`when the radiation sources 34 and 36 are turned off in a
`time-division multiplex manner.
`Although the temperature preprocessor 28 and the POS
`preprocessor 38 are shownas separate blocks in FIG. 2, they
`might actually be different software functions executed by a
`single microprocessor 40. In the preferred embodiment, the
`first and second radiation sources 34 and 36 are coupled to
`tespective ones of output ports 42, 44 of the microprocessor
`40,and the IR temperature sensor 26 and the photosensor 32
`are coupled to respective ones of two input ports 46, 48 of
`the microprocessor 40.
`With regard to the use of signals relating two different
`wavelengths to determine oxygen saturation, the technique
`is well known and understood by those familiar with the
`field of art. The technique is based on the recognition that the
`difference in signals related to the absorption and/or reflec-
`tion of light at two different wavelengths can be used to
`determine the proportion of oxygen carrying hemoglobin in
`the blood. Similarly, the variations in such signals can be
`used to monitor pulse rate and/or respiration rate in accor-
`dance with conventional techniques.
`Operation of the circuit 22 is powered by a battery 50 in
`the preferred implementation because of the power required
`by the circuit 22.
`Various modifications and substitutions can be made
`without departing from the scope of the invention.
`For example, the IR temperature sensor 26 can be placed
`so that it touches the tissue of the ear canal and is aimed at
`or near the tympanic membrane 52. The ear plug 56 is
`designed to provide sufficient thermal insulation such that
`insertion of the IR temperature sensor 26 does not cool the
`tissue being measured or even whenthe tissue is cooled by
`direct contact, a thermal equilibrium is re-established over a
`short period of time as the sensor 26 remains in place.
`With reference to FIG. 4, pulse oximetry can also be
`measured by an optical sensor 70. The optical sensor 70 can
`be held in place by a clip 72 clamped to the ear lobe 74. An
`ear muff 76 can be used to support other components 78,
`such as the preprocessor and the communication circuit.
`There are sources located on the otherside of the ear lobe so
`that the sensor can sense absorption ofthe optical signal by
`the ear lobe.
`Heart rate can also be measured from thetissues of the ear
`using optical plethysmography techniques which detect
`instantaneous changes in the volume of the blood in the
`tissue. The detection is performed by projecting an optical
`tadiation to the tissue of the ear and measuring changes in
`opacity or reflectance resulting from changes in the volume
`of blood in the tissue.
`
`In other implementations, heart rate can also be monitored
`from the tissues of the ear canal using either pulse oximetry
`or optical plethysmography techniques.
`
`6
`In other implementations, heart rate can also be monitored
`from the ear lobe or concha. With reference to FIG. 5, one
`or more light sources 58 can be provided to project optical
`radiation 60 to the external tissues of the ear 62 from one
`side of the ear. The optical radiation transmitted through the
`ear lobe 62 is measured by one or more photosensors 64
`placed on the other side of the ear. Measurements of the
`optical radiation transmitted through the ear lobe 62 are sent
`to an external processor 66 through a preprocessor 68. The
`external processor 66 processes data from the photosensor or
`photosensors 64 using conventional pulse oximetry tech-
`niques to determine the heart rate. In such implementation,
`the light source or sources 58, photosensor or photosensors
`64 and processor 66 can be supported by an ear muff 69
`placed at the patient’s ear.
`While the above shows how heart rate is measured by
`detecting optical radiation transmitted through the ear lobe,
`heart rate can also be monitored by measuring optical
`radiation reflected from the ear lobe or concha(including,
`e.g., use of pulse oximetry radiation).
`Heart rate can also be monitored fromthe ear lobe or
`concha through the use of light sources, sensors, and data
`processing of optical plethysmography (e.g., through trans-
`mission or reflection measurements).
`Bio-potentials associated with the cardiac cycle and trans-
`ducableat the surfaceof the skin (i.e., electro-cardiogram or
`ECG)can be measured at numeroussites on the body. Heart
`rate can therefore be monitored by applying two electrodes
`at any two locations on or near the ear and measuring the
`ECG bio-potential between the two locations. Similarly,
`heart rate can be monitored from any two locations on or
`near the ear using known impedance plethysmography tech-
`niques.
`In accordance with such techniques, a constant amplitude
`electrical current is applied between two terminals placed
`respectively at the two locations. The electrical potential
`measured across the two terminals as a result of the applied
`electrical current is detected. This electrical potential is
`directly proportional to the impedance of the tissue. Since
`electrical conductivity changes when the amount of blood
`passing through the ear changesin responseto the heart beat,
`by measuring changesin the electrical potential across the
`two terminals, variations in the amount of blood passing
`through the ear, and therefore the heart rate, can be mea-
`sured.
`
`the frequency
`In accordance with the Raman Effect,
`and/or phase of electromagnetic radiation are changed when
`passing through a transparent medium. Oxygensaturation of
`arterial blood can therefore be measured from theear lobule,
`concha,anthelix, helix, triangular fossa, tragus or antitragus
`by projecting,
`through fiber optics, an optical radiation
`through the semi-transparenttissue.
`The present invention can also be used to measure gases,
`glucose,
`lactate, and other organic compounds in blood
`through non-invasive spectroscopic means.
`Alternative sites on the ear can also serve as sites for
`placement of electrodes for the measurement of
`electrocardiograms, electroencephalograms,
`electromyograms, and event-related potentials. However, in
`the measurementof bio-potentials, it is sometimes necessary
`to locate another (second) electrode and, perhaps, telemetry
`transmitter at another site on the body in order to obtain a
`potential difference with a usable vector.
`The support for the circuitry can be an ear mold whichis
`custom-made to fit the ear of a patient such that the sensors
`are located in a way to ensure the transduction of a signal
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`65
`
`0010
`
`0010
`
`

`

`5,673,692
`
`7
`the
`from the tympanic membrane. On the other hand,
`support can also have a standardized shape and/or size, or
`have an adjustable shape and/or size so that a monitoring
`device can be available to any patient during emergency. The
`support can be made with either disposable or non-
`disposable material.
`FIGS. 6 through 10 show a housing for sources, a sensor
`and a detector such as those represented in FIG. 2, but with
`the sources and sensor using the ear canal lining, while the
`detector uses the tympanic membrane. FIG. 10 shows the
`housing, in the same view as FIG. 9, but with the sources,
`sensor and detector mounted in the housing.
`The housing 76 can be made of any suitable material for
`insertion into the ear canal. Plastic-type materials which are
`readily molded, such as polyamide or nylon materials, are
`convenient and efficient examples. The housing has an inner
`end 78, to be positioned in the ear canal, and an outer end
`80.
`
`Starting at the inner end 78, there is an elongated section
`82 of the housing having a generally tapered outside wall 84,
`which is tapered outwardly (from the axis 83 of the housing)
`toward the outer end 80. This taper exists along the elon-
`gated section except for a short distance in proximity to the
`inner end 78.
`
`Toward the outer end, there is a plug section 86 of the
`housing. In position, an inner wall surface 90 of this plug
`section, which faces toward the inner end 78 of the housing,
`fits adjacent the outer ear.
`The housing is hollow in that it has an elongated section
`opening 90 through the elongated section 84 of the housing,
`leading to a plug section opening 94 throughthe plug section
`86 ofthe housing. The elongated section opening then opens
`at the inner end 78 of the housing. providing an inner end
`entrance opening 95 at that point, and the plug section
`opening similarly opens at the outer end 80.
`Along the elongated section 82 of the housing, there is
`also a pair of mounting openings through the wall of the
`section. In the view of FIGS. 6 through 10, there is a top
`mounting opening 94 and a bottom mounting opening 96.
`Such openings are shownto be positioned 180 degrees apart
`from one another along the elongated section $2 of the
`housing, but are otherwise essentially identical.
`As shownin FIG. 11, the openings and the transducers
`mounted therein need not be positioned only at 180° apart as
`depicted in FIGS. 6-10 but may preferably also be posi-
`tioned in a range of about 45° to 90° apart. In particular, as
`depicted in FIG. 11, the preferred angular separation of the
`transducers is about 60° apart. The angular separation of
`these openings and transducers significantly effects the
`signal to noise ratio of the signals detected. These detected
`signals include both skin reflectance factors as well as skin
`conductancefactors. The actual angular separation used may
`well depend on the particular transducers used as well as
`their operating wavelengths.
`As shown in FIGS. 6 and 7, when each mounting opening
`is formed,a pair of side ledgesis left for mounting purposes.
`Thus, there is an elongated pair of side ledges 98 at the top
`opening and an elongated pair of side edges 100 at the
`bottom opening.
`In FIG. 10, a top opening substrate 102 is mounted on and
`adhered to the elongated side ledges 98 of the top opening
`and a bottom opening substrate 104 is similarly mounted on
`and adhered to the elongated side ledges of the bottom
`opening. The top opening substrate carries a pair of pulse
`oximetry radiation sources 110 mounted on the substrate,
`surrounded by a bubble 112 of an appropriate mounting
`
`8
`material such as an epoxy material. In accordance with
`conventional pulse oximetry techniques as referenced
`herein, the radiation from the sources is at two different
`wavelengths. In position in the ear, such radiation then is
`transmitted toward the ear canal lining and reflects off such
`lining.
`On the bottom opening substrate 104, there is similarly
`mounted a pulse oximetry sensor or detector 113 to detect
`radiation originating from the sources, at a point after
`reflection and/or conduction from the ear lining wall, for
`pulse oximetry purposes. This sensor is also similarly sur-
`rounded by a dome shaped cover 114 of an appropriate
`mounting material, such as an epoxy material. As previously
`explained, the pulse oximetry signals, of course, can also be
`used to determine the heart rate of the patient. As previously
`indicated, the sources and detectors are appropriately con-
`nected in the apparatus shown in FIG. 2 with, however, the
`sources directed at the ear wall lining rather than the
`tympanic membrane.
`The substrates 102 and 104 can conveniently and effi-
`ciently be made of conventional materials for mounting
`electronic parts, such as conventional fiberglass or ceramic
`circuit board material. Lines of conductive material (not
`shown) are used to connect leads from the sources 110 and
`detector 113 to parts of the apparatus outside the housing. In
`FIG. 10, a single upper lead 115 to-the top substrate and a
`single lower lead 116 to the bottom substrate are shown for
`purposesof illustration. There would, however, typically be
`two leads for each of the referenced source and sensor
`components, although there could be variations in accor-
`dance with conventional electrical connection techniques.
`Rather than extending separate leads to a particular compo-
`nent from outside the housing, a coaxial-type cable could be
`used with the shield and axial wire separated and separately
`connected to a substrate conductor.
`
`In FIG. 10, at the inner end 78 of the housing 76, there is
`a thermistor, infrared sensor or detector 122 oriented to face
`the tympanic membrane and to receive infrared radiation
`from the membrane, to be used in determining the tempera~-
`ture of the patient. This sensor would also fit in the apparatus
`of FIG. 2, apart from the pointing of the sources in FIG. 2
`toward the tympanic membrane(as opposed to the ear canal
`lining). The sensor 122 can be conventionally adhered to the
`wall of the housing 76. In FIG. 10, two infrared sensor leads
`120, for illustrative purposes, are shown leading from the
`sensor to the outside of the housing. The actual number, of
`course, may vary dependingonthe nature and characteristics
`of the sensor.
`
`10
`
`25
`
`30
`
`40
`
`The sources, and sensor, for pulse oximetry may be
`operated in the visible light spectrum or in the near infrared.
`Examples of sources (light-emitting diodes) and sensors
`of the type which may be used in accordance herewith are
`sources and/or sensors: found in Dialight Corporation’s 597
`Top View CBISeries Visible, 597 Top View Infrared Emit-
`ters Series, and 597 Top View Infrared Detectors Series; and
`found in Nonin Medical, Inc.’s Adult Flexi-Form Single
`Patient Use Sensor (Part No. 9000A), Neonatal Flexi-Form
`Single Patient Use Sensor (Part No. 9000N) and Pediatric
`Flexi-Form Single Patient Use Sensor (Part No. 9000T).
`Referring now to FIG. 12, another embodiment of the
`present
`invention is shown in which communications
`between the transducers in housing 76 and the display and
`alarm devices in remote monitoring display 120 is accom-
`plished by radio. In particular, radiation sources 110 and
`radiation detector 113 are mounted in housing 76 together
`with thermal detector 122 as described above. In addition,
`
`55
`
`65
`
`0011
`
`0011
`
`

`

`5,673,692
`
`9
`electronics controller 132 is affixed to the back of housing 76
`and in turn supports transmitter package 134 forming inte-
`grated electronics package 142.
`Integrated electronics package 142 is mounted within
`foam pad 136 of ear muff 138. Batteries 140 provide power
`for the components of integrated electronics package 142
`and are conveniently positioned within foam pad 136 as
`shown. Ear muff 138 is supported on the patient’s head by
`headband 144 for convenience.
`
`10
`first and second light sources and a light sensor for
`receiving light from said light sources, said light
`sources being adapted to be aimed. away from sa