a2, United States Patent
`US 6,351,217 Bl
`(10) Patent No.:
`Feb. 26, 2002
`(45) Date of Patent:
`Kuhn
`
`US006351217B1
`
`(54) CLINICAL THERMOMETER
`
`(75)
`
`Inventor:
`
`Jens Kuhn, Ilmenau (DE)
`
`(73) Assignee: Geratherm Medical AG, Geschwenda
`(DE)
`
`(*) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`US.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/654,351
`
`(22)
`
`Filed:
`
`Sep. 1, 2000
`
`(30)
`
`Foreign Application Priority Data
`
`Sep. 3, 1999
`
`(DE)
`
`ceceseesssessscessesesecssseestessseesees 199 42 089
`
`Tint, Cn? eee eeeeeeeeeteeenesneeneeeneeneenees GOSB 23/00
`(SL)
`
`(52) US. Ch.eee 340/573.1; 340/573.7
`(58) Field of Search... 340/573.1, 573.7,
`340/584; 600/301, 474, 484
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`4,636,093 A
`5,559,497 A
`5,653,239 A *
`5,724,025 A *
`
`........... 374/186
`1/1987 Nagasakaet al.
`9/1996 Hong woes 340/573.1
`
`8/1997 Pompieet al.
`3/1998 Tavori
`....eceeeeeees 340/573.1
`
`6,030,342 A *
`
`2/2000 Amanoetal. ........... 600/301
`
`FOREIGN PATENT DOCUMENTS
`
`DE
`EP
`GB
`WO
`
`298 04 222 U1
`0 424 102 Al
`2 286 684
`WO 90/09570
`
`10/1998
`4/1991
`8/1995
`8/1990
`
`* cited by examiner
`
`Primary Examiner—Van T Trieu
`(74) Attorney, Agent, or Firm—Connolly, Bove, Lodge &
`Hutz LLP
`
`ABSTRACT
`(57)
`The invention relates to a clinical thermometer of a small
`design portable also by children, having a data memory 18
`and an interface 21, by which both continually monitoring
`measurements and discontinued cyclic measurements as a
`maximum thermometer may be comfortably performed at
`locations which are medically established for measuring
`body temperature. Depending on the selected setting of the
`storage rate, the temperature of the measurementlocation is
`continuously monitored or cyclic individual measurements
`are taken. For changing the modeof operation, no extra keys
`or switches are necessary which would be difficult to place
`on a small, compact housing 14.
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`13 Claims, 3 Drawing Sheets
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`U.S. Patent
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`Feb. 26, 2002
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`US 6,351,217 B1
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`U.S. Patent
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`Feb. 26, 2002
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`US 6,351,217 B1
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`U.S. Patent
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`Feb. 26, 2002
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`US 6,351,217 B1
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`US 6,351,217 B1
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`1
`CLINICAL THERMOMETER
`BACKGROUND OF THE INVENTION
`
`Small children and babies are prone to suffer from colds
`and variousinfectious diseases, e.g. the so-called children’s
`diseases (measles, smallpox, German measles,scarlet fever
`and the like). These diseases put considerable stress on the
`parents, also because of the necessity to check the child’s
`body temperature regularly in order to recognise drastic
`changes at once. To this end, the parents at night have to
`interrupt their own sleep and that of their child, which is
`unpleasant for all concerned. It would therefore be desirable
`to have a thermometer which performs such monitoring
`function automatically, takes the body temperature continu-
`ally and initiates an alarm when critical changes occur.
`It is often not easy for the parents to decide whether a
`given temperature increase is dangerous for the child. It
`would thus be most advantageous if the detected tempera-
`ture curve could be readily transmitted, e.g. by e-mail, to the
`family doctor who will use his expertise to judge the
`measurements and take appropriate steps.
`Fever can become dangerous if it causes convulsions
`which may entrain a loss of conscience. Such convulsions
`are caused by a sudden increase in temperature. A convul-
`sion of this type can occur specifically with children
`between the age of six monthsto five years. About 3 to 4 per
`cent of the children of this age are affected. As the duration
`of the attack increases, it enhances the risk of later afibrile
`effects, i.e. epilepsy. Therefore, optimum therapy is of the
`essence in an acute attack. Unless antispasmodic measures
`are taken within few minutes, the attack represents a genuine
`emergency.
`To reduce the risk of occurring, specifically re-occurring,
`convulsions during fever, it is recommendedto apply fever-
`reducing measures from a body temperature of 38.5° C. on
`as early as possible. Also in this case, a continually mea-
`suring thermometer is required which generates an alarm
`when a limit
`temperature is exceeded,
`to enable quick
`action. Since many of the endangered children are active,
`such a thermometer must be unproblematic to carry by
`children.
`
`With older, specifically helpless persons, insufficient food
`intake, chronic infections and the like may cause emaciation
`(cachexia), which in turn may lead to dangerous hypother-
`mia. A body temperature below about 30° C. mayresult in
`a state of unconsciousness making it impossible for the
`person to help himself or herself. A continually measuring
`thermometer, which generates an alarm when the tempera-
`ture falls below a limit value, allows endangered persons to
`obtain quick help in acute cases.
`Atelatively dependable medication-free method of natu-
`ral contraception is the temperature method in which a
`woman can determine the fertile days of her menstrual
`period by watching the basal temperature. Another impor-
`tant parameter in diagnosing and curing disturbances of the
`menstrual period is the wake-up temperature. The recordal
`and evaluation of the basal temperature requires a thermom-
`eter which operates as a maximum thermometer. The tem-
`perature of the measurement location is detected until the
`rising gradient reachesorfalls below a limit value. This type
`of thermometer will always give only the largest tempera-
`ture value found in a given measuring period, ie.
`the
`maximum. A cyclo-thermometer may be in the form of a
`maximum thermometer which stores the temperature maxi-
`mum along with the time and a day numberand upon request
`displays this information or transmits it to a personal com-
`puter.
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`A plurality of suggestions have been made for continu-
`ously monitoring the body temperature, particularly of small
`children; compare DE 298 04 222 U1, US. Pat. No. 5,559,
`497, FR 26 94 977 Al, WO 90/09570, DD 254 643 A and
`GB 2 286 684 A. These thermometers, however, have no
`maximum function and are therefore unsuited for taking
`individual measurements.
`
`Many documents propose to fix a thermometer to the
`wrist; compare U.S. Pat. No. 5,559,497, FR 26 94 977 Al
`and GB 2 286 684 A. The wrist, however, is unsuited for
`taking continuously monitoring body temperature
`measurements, since the measurement results may very
`strongly depend on the surrounding temperature and on the
`location of measurement being covered (suchas byclothing,
`a blanket, position of the wrist underneath the body). The
`calibration of the thermometer with respect to the body core
`temperature by meansof a reference sensor, as provided in
`GB 2 286 684 A does not solve this problem since the
`calibration is valid for one given environmental situation
`only.
`EP 0 424 102 A1 discloses a thermometer for women for
`daily determining the basal temperature. The thermometer
`operates as a maximum thermometer but is unsuited for
`taking continuously monitoring measurements.
`U.S. Pat. No. 4,636,093 discloses a temperature measur-
`ing arrangement, by which temperature values detected at a
`number of locations by means of one or a plurality of
`radiation thermometers can be performed with a portable
`recording device and subsequently transmitted to a process-
`ing equipment. Each measurement is taken by manually
`operating the recording device and mayrepresent the instant
`temperature or the maximum value that occurs within a short
`period.
`
`SUMMARYOF THE INVENTION
`
`is an object of the invention to provide a clinical
`It
`thermometer which permits taking both continually moni-
`toring measurements and discontinuous cyclic measure-
`ments as a maximum thermometer.
`
`This object is met by a clinical thermometer having a
`housing, a temperature sensor connected to said housing, a
`measuring circuit disposed in said housing and including a
`micro controller and a data memory for recording the
`temperature value measured by said temperature sensor, said
`data memory having a storage rate, a voltage supply for
`powering said measuring circuit, and a mode switch for
`switching the storage rate of said memory between a con-
`tinuous operation mode,
`in which the temperature of a
`measurement
`location is continuously monitored, and a
`discontinuous operation mode, in which individual tempera-
`ture measurements are recorded.
`
`The setting of storage rate determines whether the ther-
`mometer continously monitors the temperature of the mea-
`surementlocation or performs cyclic or individual measure-
`ments. For changing the mode of operation, no extra switch
`is required, which would be difficult to place on a small,
`compact housing.
`The storage rate is adapted to be set to zero to switch-over
`to the discontinuous operation mode. For any storage rate
`different from zero, the thermometer operates as a continu-
`ally measuring thermometer which regularly stores the
`actual temperature in a data memory at regular intervals in
`accordance with the selected storage rate. In the discontinu-
`ous operation mode, the thermometer preferably operates as
`a maximum thermometer.
`Since the thermometer is to be used also with small
`
`children, any inadvertent switching-off or reconfiguration
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`US 6,351,217 B1
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`3
`must be safely excluded. This is achieved by a safety switch
`which locks an on/off switch and the mode switch. The
`safety switch is preferably recessed with respect
`to the
`housing surface so that any inadvertent actuation is pre-
`vented.
`
`The thermometer preferably includes a display to
`indicate, in the continously operation mode, the day of the
`uninterrupted measurement and, in the discontinuous mode,
`the number of measurements recorded.
`
`the micro controller
`In another preferred embodiment,
`provides two independently adjustable alarm temperatures,
`and the thermometer further includes a signal generator
`adapted to be actuated by either one of the alarm tempera-
`tures. The signal generator may producean acoustical and/or
`optical alarm.
`For ensuring that the thermometer carries out its moni-
`toring function, the micro controller preferably has means
`for automatically and periodically performing a reference
`measurement and actuating the signal generator when the
`result of the reference measurementdeviates from a standard
`value. It may also have means for actuating the signal
`generator when the supply voltage falls below a critical
`value.
`
`The temperature sensor is integrated in a flexible water-
`tight cable connected to the housing. This permits the
`temperature sensor to be placed either on the inguen or in the
`axilla.
`
`Meansprovided on the housing for receiving a mounting
`adapter further allows the thermometer to be mounted in any
`suitable manner, e.g. by means of a Velcro fastener.
`An interface for transmitting the contents of the data
`memory to a remote location may be provided to enhance
`the comfort and usability of the thermometer.
`The thermometer is preferably so light and compact that
`it may easily be carried on the body for an extended time,
`even by small children.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 shows the outside of the thermometer in accor-
`dance with an embodiment of the invention.
`
`FIG. 2 is a cross-section showing the principal structure
`of the thermometer.
`
`FIG. 3 is a longitudinal section of the arrangement shown
`in FIG. 2.
`
`DETAILED DESCRIPTION OF PREFERRED
`EMBODIMENTS
`
`thermometer
`the clinical
`As shown in the drawings,
`consists of a temperature sensor 10 and an electronic mea-
`suring circuit 13. The temperature sensor 10, which is
`constituted by a temperature detector 11 and a cable 12, is
`shaped so that
`it permits measurements to be taken
`inguinally, axillarily or orally.
`For continual temperature measurements to be taken from
`sick small children and babies, the measuring cirucit 13 is
`fixed externally on the belly side of the diaper, and the
`temperature sensor 10 is placed inside the diaper so that it
`can detect the inguinal temperature. For fixing, a suitable
`mounting adapter with a Velcro strip or clip (not shown) is
`selected from thermometer accessories and inserted into
`
`adapter receiving grooves 15 provided on the housing 14 of
`the measuring circuit 13.
`The measuring circuit 13 includes, on a circuit board 16
`provided inside the housing 14, a micro controller 17 with
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`an integrated data memory 18, a battery 19, an acoustic
`signal generator 20 and an interface 21 for connection to a
`personal computer or a telemetry device; on the upper side
`of the housingit further has a display section 22 with various
`displays, input switches 23 to 26 which are accessible from
`the upper side, and a recessed safety switch 27.
`Aclock provided in the micro controller 17 drives a time
`display 28 on the display section 22 such that the actual time
`is displayed even when the thermometer is turned off. This
`facilitates the use of the thermometer because the user does
`not have to set the time.
`
`Whenthe thermometeris turned on by meansof the on/off
`switch 23, the actual temperature is displayed in a tempera-
`ture display 30 and a numberrepresenting the day of
`measurementis displayed in a day display 29 of the display
`section 22.
`
`The thermometer starts taking measurementsat a rate of
`1/s. This enables the user to recognise immediately that the
`thermometer is functioning. After a period of 15 min, the
`measuring rate is automatically changed to a smaller value
`of 1/min, to save energy.
`The mode switch 24 allows selecting one of a number of
`setting levels. On the individual levels, values are changed
`or functions are initiated by means of up and down switches
`25, 26. The following seven levels are provided:
`1. Normal measuring mode.
`Time.
`. Alarm 1.
`. Alarm 2.
`
`. Storage rate (standard: 1 h).
`. Data transmission.
`. Clear.
`The clock maybe reset by meansof the function switches
`24 to 26 at any time, for instance after a changeofthe battery
`19. Executing the clear command will clear the data memory
`18 and reset the day counter.
`The alarm temperatures and the storage rate of the ther-
`mometer can be set in accordance with the patient’s own
`discretion or medical advice;
`for example,
`lower alarm
`temperature: 35.0° C., upper alarm temperature: 37.5° C.,
`storage rate: 1/h. With this setting, the signal generator 20 is
`actuated when the child’s body temperature falls below 35°
`C., e.g. because the blanket no longer covers the child. The
`alarm is also actuated when the thermometer is removed
`from the measuring location due to uncontrolled movements
`of the child. The acoustical signal generator 20 is further
`actuated when the child’s temperature rises above 37.5° C.
`due to illness.
`
`Remote monitoring of the child’s body temperature is
`possible by means of room monitoring devices (baby
`phones) which are widely used nowadays. The child’s
`parents are acoustically alarmed when a dangeroussituation
`occurs. The signal generator 20 may be so structured that it
`generates an optical signal instead of, or in addition to, an
`acoustical signal.
`A signal will also be generated when the voltage of the
`battery 19 falls below a critical value and change of the
`battery becomes necessary to maintain the monitoring func-
`tion.
`
`the last detected
`the selected storing rate of 1/h,
`At
`temperature value is recorded every hour along with the
`measuring time and day number. The recorded data sets,
`including temperature, measuring time and day number,
`may be displayed at any time by meansof the up and down
`switches 25 and 26.
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`US 6,351,217 B1
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`Whatis claimedis:
`
`1. A clinical thermometer having
`
`a housing,
`a temperature sensor connected to said housing,
`a measuring circuit disposed in said housing and includ-
`ing a micro controller and a data memory for recording
`the temperature value measured by said temperature
`sensor, said data memory having a storage rate,
`a voltage supply for powering said measuring circuit,
`a mode switch for switching the storage rate of said
`memory between a continuous operation mode,
`in
`which the temperature of a measurement location is
`continuously monitored, and a discontinuous operation
`mode, in which individual temperature measurements
`are recorded, and
`switching means for selecting the storage rate at which
`temperature measurementvalues taken in said continu-
`ous operation mode are entered into said data memory.
`2. The thermometer of claim 1, wherein said storage rate
`is adapted to be set to zero for said discontinuous operation
`mode.
`
`5
`It is likewise possible to transmit the detected data to a
`personal computer via the interface 21, which is preferably
`formed as an infrared interface. The measured temperature
`curve may be graphically displayed on the computer and
`may be further transmitted, e.g. by e-mail, for examination
`by a physician.
`The safety switch 27 serves to prevent inadvertent turning
`off of the thermometer or resetting, e.g. the values of the
`alarm temperatures. When the switch 27 has been actuated,
`the thermometer no longer responds to actuations of the
`on/off switch 23 and the mode switch 24, whereas the
`temperature display 30 and the time display 28 remain
`active. The stored measuring values also remain available
`for display by pressing the up and down switches 24, 25.
`Convulsions caused by fever can occur not only with
`babies but also with children up to the age of six or more
`years. Since such convulsions may occur at any time, the
`body temperature must be monitored continuously.
`With diaper wearing children, the thermometeris applied
`as described above. For older children, the thermometer can
`be mountedat the outer side of their pants by meansofa clip,
`with the sensor being placed at
`the inguen. As another
`possibility, the thermometer may be carried in a holster on
`the chest. This permits placing the temperature sensor 10 in
`the axilla, where it is fixed by meansof a special tape (with
`a skin compatible adhesive).
`When the temperature suddenly exceeds the set alarm
`temperature, an alarm is generated. The child or another
`person nearby maythen take suitable measures to prevent a
`5. The thermometer claim 1, further including a day
`convulsion or call for qualified help (emergency doctor).
`display.
`A problem often occurring with older persons in need of
`6. The thermometer claim 1, wherein said micro control-
`care resides in malfunctions of the body’s own temperature
`ler provides two independently adjustable alarm
`regulation. Dangerous hypothermia may then occur. To
`temperatures, said thermometer further including a signal
`avoid such accidents, the body temperature may be continu-
`generator adapted to be actuated by either one of said alarm
`ously monitored by meansof the thermometer. Signal trans-
`temperatures.
`mission to nursing personnel may be done with the aid of a
`room monitoring device (baby phone). Suitable measuring
`7. The thermometer of claim 6, wherein said signal
`generator is an acoustical signal generator.
`locations are at the inguen or in the axilla.
`8. The thermometer of claim 6, wherein said signal
`The thermometer is switched over from a continually
`generator is an optical signal generator.
`measuring monitoring thermometer to a maximum ther-
`9. The thermometer of claim 6, wherein said micro
`mometer by setting the storage rate to zero. In the latter
`controller includes meansfor automatically and periodically
`operation mode, the thermometer maybe used for recording
`performing a reference measurement and actuating said
`the basal temperature. As a special feature of this mode, any
`signal generator whenthe result of said reference measure-
`alarm values set are not monitored. If a plurality of mea-
`ment deviates from a standard value.
`surements are taken on the same day, only the highest
`10. The thermometer of claim 6, wherein said micro
`temperature value measured will be recorded.In this way,it
`controller actuates said signal generator whenthe voltage of
`is possible to repeat a faulty measurement without distorting
`
`the temperature curve by duplicate measurements on the said voltage supply falls belowacritical value.
`same day. The measured temperature value is recorded along
`11. The thermometerof claim 1, wherein said temperature
`with the time and day number. The evaluation of the
`sensoris integrated in a flexible water-tight cable connected
`measured temperature curve may be done either manually
`to said housing.
`by simply copying the measuredresults into a table or, more
`12. The thermometer of claim 1, further including means
`comfortably, by transmitting them to a personal computer.
`provided on said housing for receiving a mounting adapter.
`The clinical thermometer with its storage rate set to zero
`13. The thermometer of claim 1, further including an
`may also be used at a normalclinical thermometer.
`interface for transmitting the contents of said data memory
`to a remote location.
`Possible applications for the clinical thermometer are in
`hospitals,
`in monitoring babies or in the post-operative
`monitoring of patients.
`
`3. The thermometer of claim 2, which in said discontinu-
`ous operation mode operates as a maximum thermometer.
`4. The thermometer claim 1, further including an on/off
`switch, and a safety switch for locking said on/off switch and
`said mode switch.
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