Abstract:
An improved electronic thermometer for rectal, oral, and axillary temperature measurements includes a removable module that houses a temperature sensitive probe and isolation chamber as well as a supply of clean, uncontaminated disposable probe covers on a single color coded module. Each removable module is interchangeably operable with a single temperature calculating unit. This thermometer design reduces the risk of patient exposure to all of the common sources of contamination encountered in the use of electronic thermometers by isolating the probe, the isolation chamber, and a supply of disposable probe covers on one dedicated removable module.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to electronic thermometers, particularly those which utilize temperature sensitive probes and probe covers.  
         BACKGROUND OF THE INVENTION  
         [0002]    Electronic thermometers have been widely used for quick and accurate measurements of body temperature. A temperature sensing probe is inserted orally, rectally, or in an axillary (under the arm) position to measure a patient&#39;s temperature. The temperature sensitive probe is connected to the thermal circuitry in a temperature calculating unit by an electrical cable. The temperature sensitive probe generates a signal. This signal passes through the electrical cable to the temperature calculating unit, where the signal is converted into an equivalent temperature reading. The temperature calculating unit has a digital display which shows the calculated temperature reading.  
           [0003]    Before each measurement, a disposable plastic probe cover is placed over the probe. The probe cover is then disposed after each temperature reading and a new probe cover is used for each subsequent measurement. When not in use, the temperature sensitive probe is stored in a housing, well, or recess associated with the temperature calculating unit to minimize probe damage and probe contamination.  
           [0004]    Prior art electronic thermometers are susceptible to at least three major sources of contamination in typical use. First, these thermometers employ the same temperature sensitive probes for oral, rectal, and axillary temperature measurements. Even though disposable plastic probe covers are used for each measurement, cross-contamination may still result from use of the same probe. Therefore, rectal or axillary contaminants on the probe may be passed orally to the same patient, or other patients.  
           [0005]    The second source of contamination involves the probe storage chamber. Probes are stored in a single housing recess connected to the temperature calculating unit. This recess, once contaminated, may spread contamination to other probes as they may be interchangeably stored in the same recess. Over time the storage chamber may also collect debris and contamination from the storage of multiple probes. So again, contaminants on the probe from rectal or axillary use may be passed orally to the same patient, or other patients.  
           [0006]    The third source of contamination relates to the disposable probe covers. Each time a patient&#39;s temperature is measured, the probe is inserted into a box of unused disposable probe covers. The probes of the prior art share a common source of probe covers, so different probes are repeatedly inserted into the same carton. The probe, then, once contaminated, may spread contamination to other unused probe covers. Contaminants deposited on the unused probe cover may then be passed on to the same patient, or other patients.  
           [0007]    Since electronic thermometers are used for oral, axillary, and rectal temperature measurements, universal color codes have been adopted by hospitals, using red probes for rectal temperature measurements and blue probes for oral and axillary temperature measurements. This color coding system makes it very easy for the healthcare practitioner to use the proper probe for each temperature reading, reducing the potential for cross-contamination.  
           [0008]    The use of a blue probe for oral and axillary temperature measurements and a red probe for rectal temperature measurements reduces the first source of contamination. Separating probe use in this manner also improves patient perception issues related to the health practitioner using the same probe for all types of temperature measurements. Such practice, however, requires two thermometer units to be available at each location if the probes are not interchangeable. Maintaining two units at each location has been considered an inefficient and costly measure. Such a practice also makes the practitioner susceptible to using the most convenient, yet inappropriate, unit.  
           [0009]    Some have developed thermometers with detachable probe units. U.S. Pat. No. 4,008,614, assigned to Johnson &amp; Johnson, New Brunswick, N.J., discloses an electronic thermometer unit usable with an oral temperature probe permanently attached to an oral isolation chamber. Similarly, there is a rectal probe permanently attached to a rectal isolation chamber. Connecting the probe and isolation chamber together as one unit thus precludes the inadvertent use of a probe with the wrong isolation chamber.  
           [0010]    Similarly, U.S. Pat. No. 4,619,271, assigned to Cheesebrough-Pond&#39;s, Inc., discloses an independent replaceable probe unit including a probe member and a probe chamber for holding the probe member, which can be easily removed and replaced together as a unit. The probe, cable, and isolation chamber are all the same color. The permanent connection assures that the health practitioner stores the probe in the proper isolation chamber, thus reducing the risk of contamination leading to infection. A significant limitation of each of these approaches is that even though the probe is permanently attached to an isolation chamber, both the oral and rectal probe units will be repeatedly and interchangeably inserted into the same box or boxes of probe covers, still exposing the probe to possible contamination.  
           [0011]    U.S. Pat. No. 4,572,365, assigned to Cheesebrough-Pond&#39;s Inc., discloses an improved probe cover holding and dispensing arrangement, the objective of which is to provide convenient access to clean probe covers. An electronic thermometer housing contains a chamber for receiving a carton of probe covers. Once the carton is inserted and secured within the housing, an aperture in the thermometer housing, normally closed by a sliding cover, provides access to the inserted carton of probe covers. Still, in this arrangement, the probe and isolation unit may be interchanged between oral and rectal without changing the cartridge of probe covers. Both oral and rectal probe units share access to the same source of probe covers, providing a source of cross-contamination.  
           [0012]    U.S. Pat. No. 4,260,058 to Seymour et al. discloses an arrangement of mounting a holder on top of the thermometer device to receive a cartridge of probe covers. However, in this approach, probe covers are still stored with the temperature calculating unit. The disclosed arrangement does not require a dedicated probe and isolation chamber. This again may allow both oral and rectal probes access to a shared source of probe covers, providing a source of contamination.  
           [0013]    Each of these prior art approaches fails to address the exposure to contamination as each temperature sensitive probe, oral or rectal, is repeatedly inserted into the same box or boxes of probe covers. In each approach, the same source of probe covers is used whether the covers are stored in connection with the temperature calculating unit or separate from the thermometer altogether.  
           [0014]    Currently there is a need for an electronic thermometer which reduces patient exposure to all sources of cross-contamination, aids in infection control, and provides a clean, uncontaminated, readily accessible source of probe covers.  
         SUMMARY  
         [0015]    It is therefore an object of this invention to provide a thermometer that reduces all three major sources of contamination and cross-contamination by eliminating the use of the same probe for oral, axillary, and rectal temperature measurements, the use of the same storage chamber for each type of probe, and the use of the same supply of probe covers for each type of probe.  
           [0016]    It is another object of this invention to provide a removable module capable of receiving and storing both a temperature sensitive probe and a clean, uncontaminated supply of disposable probe covers.  
           [0017]    It is a further object of this invention to provide a removable module with an isolation chamber that prevents the storage of a temperature sensitive probe with a probe cover remaining on the probe.  
           [0018]    It is yet another object of this invention to provide a removable module that allows the practitioner to readily view a supply of probe covers through a transparent module housing without disassembling or physically contacting the removable module.  
           [0019]    It is still another object of this invention to provide a module housing which aids in infection control by being easily cleaned or inexpensively replaced.  
           [0020]    The present invention reduces the risk of a patient&#39;s exposure to all of the common sources of contamination encountered in the use of electronic thermometers. The minimization in risk is accomplished by isolating the storage of the temperature sensitive probe and the disposable probe covers used for oral, axillary, and rectal temperature measurements into dedicated units, or modules.  
           [0021]    This invention features at least two types of removable modules interchangeably operable with one temperature calculating unit. The removable module is comprised of a probe assembly and a module housing. The module housing includes two chambers, one to store the probe and one to store a fresh supply of probe covers. Each of the module housing and probe assembly are color coded according to the standard convention of red for rectal measurements and blue for oral and axillary measurements.  
           [0022]    In the described embodiment, a red probe assembly is attached to a red module housing, the housing containing an isolation chamber to store the temperature sensitive probe and a storage chamber to store a supply of disposable probe covers. Similarly, a blue probe assembly is attached to a blue module housing, the housing containing an isolation chamber to store the temperature sensitive probe and a storage chamber to store a supply of disposable probe covers. The removable module requires that the rectal probe, with the supply of probe covers, is used only with the rectal probe. These dedicated modules prevent the commingling of the probe, the isolation chamber, and the probe cover supply during temperature measurement, thus minimizing thermometer contamination.  
           [0023]    Another feature of the present invention is that the module housing may be made of a translucent or transparent material. The transparent, or partially transparent, housing allows the healthcare practitioner to conveniently view the remaining supply of probe covers at any given time. The carton of disposable probe covers described in the preferred embodiment has a tear away top and/or side panels. When these cartons are used together with the transparent or partially transparent removable module, the healthcare practitioner can view and count the remaining probe covers through the module housing. This improved design provides an easily viewable arrangement that helps avoid the necessity to physically contact the housing or probe covers in order to check the remaining supply.  
           [0024]    These and additional features and advantages of the invention disclosed here will be further understood from the following detailed disclosure of the preferred embodiment. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]    [0025]FIG. 1 is a perspective view of an electronic thermometer according to the present invention.  
         [0026]    [0026]FIG. 2 is a perspective view of an electronic thermometer showing a removable module being secured to a temperature calculating unit.  
         [0027]    [0027]FIG. 3 is a rear perspective view of the removable module of FIGS. 1 and 2.  
         [0028]    [0028]FIG. 4 is a rear perspective view of a temperature calculating unit showing the connection means for securing to the removable module.  
         [0029]    [0029]FIG. 5 is a rear perspective view of a removable module showing the connection means for securing to the temperature calculating unit.  
         [0030]    [0030]FIG. 6 is a rear perspective view of an alternate embodiment of a removable module.  
         [0031]    [0031]FIG. 7 shows a perspective view of a carton design to hold disposable probe covers. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]    [0032]FIGS. 1 and 2 show a thermometer  10  according to the present invention. Thermometer  10  includes a temperature calculating unit  200  to which a removable module  100  is secured. When removable module  100  is secured to temperature calculating unit  200 , a first connector component  120  and a second connector component  220 , shown in FIGS. 4 and 5, are properly aligned and together form a connection. This connection allows a signal detected by probe  161  to be transmitted from removable module  100  to temperature calculating unit  200 . Once received the temperature calculating unit  200  converts the signal to a temperature reading  280 . Temperature reading  280  is observed through a display window  282 .  
         [0033]    With reference now to FIGS. 3 and 5, removable module  100  comprises a temperature sensitive probe assembly  160  and a module housing  180 . The probe assembly  160  further comprises a probe  161 , an electrical cable  162 , and the first connector component  120 . Temperature sensitive probe  161  is attached to electrical cable  162 , which is connected at the opposite end to the first connector component  120 . Probe assembly  160  locks into module housing  180  at a housing orifice  122 . Probe assembly  160  may be unlocked and detached from the module housing  180  for replacement if needed, but under normal operating conditions it is fixedly attached to the module housing  180 .  
         [0034]    Module housing  180  contains a isolation chamber  140  and a storage chamber  182 . As best shown in FIG. 5, isolation chamber  140  is positioned in the center of the backside wall of module housing  180 . Probe  161 , when not in use, is inserted into the isolation chamber  140 . When the removable module  100  is in its secured position to the temperature calculating unit  200 , the probe  161  rests between the temperature calculating unit  200  and the storage chamber  182 , providing additional physical protection to probe  161 . Although this is the preferred location, the isolation chamber  140  may be located anywhere within module housing  180  for purposes of this invention. The inside diameter of the isolation chamber  140  corresponds to the outside diameter of the probe  161  such that probe  161  cannot be inserted into the isolation chamber  140  with a probe cover  184  still attached to probe  161 .  
         [0035]    Since the probe  161  and the isolation chamber  140  are both components of the same removable module  100 , the probe  161  can be stored in one and only one isolation chamber  140 , thus reducing the possibility of cross-contamination and spread of infection. If there is concern that the isolation chamber  140  has in any way been contaminated, the entire removable module  100  may be removed for submersion cleaning. Alternatively, the module housing  180  may be inexpensively replaced.  
         [0036]    At the bottom of isolation chamber  140  there is a switch actuating device, such as a paddle indicator  145  shown on FIG. 5, which triggers an automatic on/off mechanism. When the probe  161  is inserted into isolation chamber  140  during periods of non-use, the probe  161  pushes the paddle indicator  145 , bending it into contact with button  245  on temperature calculating unit  200  (shown on FIG. 4). Button  245  is linked to the electronics of the temperature calculating unit  200 . When depressed, button  245  causes the temperature calculating unit  200  to turn off. Upon withdrawal of the probe  161  from the isolation chamber  140 , the paddle indicator  145  releases. This causes the temperature calculating unit  200  to turn on and prepare for a temperature measurement. This automatic on/off mechanism conserves the battery life of the temperature calculating unit  200 .  
         [0037]    Paddle indicator  145  may also be used as a reset button, indicating when a new temperature reading may be taken. If the temperature calculating unit  200  has a timed shut off mechanism, the paddle indicator  145  may be used to reactivate the temperature calculating unit  200 . This may be accomplished by inserting and removing probe  161  from isolation chamber  140 , thus triggering the paddle indicator  145  and turning on temperature calculating unit  200 . The paddle indicator  145  may be any type of mechanical, electrical, magnetic or optical switch capable of differentiating between the presence and absence of the probe  161  in the isolation chamber  140 .  
         [0038]    Referring now to FIG. 3, module housing  180  also contains the storage chamber  182 . A carton  186  of disposable probe covers containing disposable probe covers  184  fits snugly into the storage chamber  182 . The carton  186  may be perforated with tabs such that the practitioner can pull a perforated tear away tab and expose several probe covers  184 . For example, FIG. 7 shows a carton  186  used with the current embodiment. A perforated top tab  187 , when pulled, tears a portion of the top of carton  186  to provide an opening for the probe  161  to insert into a disposable probe cover  184 . Similarly, a side panel perforation  188  may start at the top and remove a side panel. The cartons  186  may be designed with one or both of the perforated top tab  187  and the side panel perforation  188 . As will be described in more detail below, these designs provide a convenient means for the practitioner to take inventory of the supply of probe covers  184  contained within storage chamber  182 .  
         [0039]    In an alternate embodiment, the storage chamber  182  may contain means to prevent the box of disposable covers from being removed and used interchangeably with other removable modules  100 . For example, as shown on FIG. 3, the storage chamber  182  may contain small projections  189  that puncture the sides of the carton of probe covers  186  such that if one attempts to remove the carton, the carton rips. In another embodiment, the carton  186  may have a perforated bottom that tears. Therefore, if the carton is removed, the bottom would tear out. The practitioner would then need to insert a fresh carton  186  of probe covers  184  into the storage chamber  182 . This deters one from switching the probe covers from one removable module to another, increasing the potential for cross-contamination.  
         [0040]    The entire removable module  100 , including the probe  161 , the electrical cable  162 , the first connector component  120 , and the module housing  180 , is color coded according to the standard convention of blue for oral and axillary measurements and red for rectal measurements. In addition to being color coded, the module housing  180  of the present embodiment is transparent or translucent. Such a transparent housing allows the practitioner to conveniently view and count the number of probe covers  184  remaining in the carton  186  at any given time. Transparency of the module housing  180  also allows the practitioner to read the information on the carton  186 , including instructions for use, warnings, and reordering information. The completely transparent module housing  180  is one example of the present invention and should not be limiting to the invention.  
         [0041]    The module housing  180  may have, for example, one transparent portion only, such as any one side, top, front, or back panel. When the carton  186  shown in FIG. 7 contains a top perforated tab  187 , the contents may be viewed through a transparent top. Similarly, when the carton  186  contains a side panel perforation, the contents may be viewed through a transparent back panel on the module housing  180 . In these situations it is necessary only to have one transparent or translucent top portion or side panel to the module housing  180  for viewing and counting.  
         [0042]    In an alternate embodiment shown in FIG. 6, storage chamber  182  is enclosed by a transparent cover  165  that pivots open on module housing  180 . The storage chamber  182  will remain closed when not being used. To access the probe covers  184 , cover  165  may pivot open around bushing  164 . Again, the supply of covers  184  may be viewed through cover  165 .  
         [0043]    The module housing  180  has fastening means to aid in mounting the removable module  100  to the backside of the temperature calculating unit  200 . As best shown in FIGS. 4 and 5, the fastening means used in the current embodiment are tracks  170  and  172 , which are molded recesses in module housing  180 . These tracks  170  and  172  receive rails  270  and  272  on the temperature calculating unit  200 . In addition, the module housing  180  contains securing means  142  and  144 , which are also molded recesses in the module housing  180 . Recesses  142  and  144  receive securing means  242  and  244  located on a mounting surface  240  of the temperature calculating unit  200 . Removable module  100  is attached to the temperature calculating unit  200  by first aligning the rails  270  and  272  with tracks  170  and  172  and securing means  142  and  144  with securing means  242  and  244 , then sliding the removable module  100  down on to the mounting surface  240  until a locking tab  166  snaps into place over the top edge of the temperature calculating unit  200 . It should be understood that fastening means, securing means, and locking tab, as defined by this invention, could be any connection device or configuration of connection devices that serve to firmly secure the removable module  100  in position on the temperature calculating unit  200 .  
         [0044]    Temperature calculating unit  200  has a second connector component  220  located on the side to which the removable module  100  is mounted. Second connector component  220  is wired to the thermometer circuitry within the temperature calculating unit  200 . When the removable module  100  is secured to the temperature calculating unit  200 , first connector component  120  and second connector component  220  mate to form an electrical connection. The temperature calculating unit  200  receives the signal detected by probe  161 , transmitted through first and second connector components  120  and  220 , and converts the signal into a temperature reading  280 . The resulting temperature reading  280  is observed through the display window  182 .  
         [0045]    The circuitry of temperature calculating unit  200  is powered by a battery  400 . The battery  400  is accessed through a cover  246  that fits into orifice  247  within mounting surface  240 . In the preferred embodiment shown in FIG. 4, cover  246  is made from rubber to create a water tight seal enabling the entire temperature calculating unit  200  to be submersed in water for cleaning. The cover  246  in this preferred embodiment further comprises the securing means  242  and  244 . To replace battery  400 , cover  246  is peeled away from the mounting surface  240  to expose the battery  400 .  
         [0046]    Referring again to FIGS. 4 &amp; 5, in an alternate embodiment removable module  100  and temperature calculating unit  200  also include means to detect the type of removable module  100  secured to the temperature calculating unit  200 . Such means may include a two part switch which enables the temperature calculating unit  200  to sense the presence of an object connected to mounting surface  240 . Temperature calculating unit  200  may have a plurality of recesses  320  on the mounting surface  240 , each recess  320  containing a trigger device  322 . There may be a plurality of corresponding protrusions, such as posts  310 , on removable module  100 . When removable module  100  is connected to temperature calculating unit  200 , posts  310  fit into recesses  320 , triggering switches  322 . Switches  322  are then sensed by temperature calculating unit  200 . Each type of removable module  100  may have a different number or location of posts  310 . For example, an oral module  100  may have one post  310  which corresponds to switch  322  within recess  320  while the rectal module may have no posts  310  to trigger switches  322 . Two alternative signals result. These two part switches then enable temperature calculating unit  200  to detect the type of removable module attached. Once the module type is detected temperature calculating unit  200  calibrates in order to make the appropriate temperature measurements. Additionally, including two recesses on mounting surface  240  provide the temperature calculating unit  200  with the capability of differentiating four different types of modules and operating accordingly. It should be understood, however, that the two part switches described may consist of any known electrical, mechanical, magnetic or optical switch.  
         [0047]    In another alternate embodiment first and second connector components  120  and  220  may carry encoded information related to probe identity and associated calibration parameters. Such encoded information enables temperature calculating unit  200  to detect the type of removable module  100  attached. As shown on FIGS. 4 &amp; 5, spring loaded posts  121  and pogo pins  123  on first connector component  120  may be used to engage contact pads  221  on second connector component  220 . Again, for purposes of this invention, the first and the second connector components may be any mechanical, electrical, magnetic or optical contacts such that when the two connection components are in proximity, a signal can pass from the removable module  100  to the temperature calculating unit  200 . Thus, when removable module  100  is connected to temperature calculating unit  200 , temperature calculating unit  200  reads the encoded information carried by the attached removable module  100  and automatically sets the corresponding operating conditions.  
         [0048]    In both alternate embodiments, when the oral/axillary module  100  is connected to the temperature calculating unit  200 , temperature calculating unit  200  reads the identity of the oral/axillary probe  161 . Second connector component  220 , connected to the electronic circuitry of the temperature calculating unit  200 , in turn causes the display of an oral/axillary icon  283  located within window  282 , as shown on FIG. 1. This indicates to the practitioner that the thermometer  10  is ready to operate in the oral/axillary mode. Similarly, when the rectal module  100  is connected to the temperature calculating unit  200 , temperature calculating unit  200  reads the identity of a rectal module  100  and displays a corresponding icon  283  within window  282 , indicating that the thermometer  10  is ready to operate in the rectal mode.  
         [0049]    When a temperature measurement is to be taken the practitioner selects the appropriate module and mounts the removable module  100  on to the temperature calculating unit  200 . By way of example, if an oral temperature measurement is desired, the blue removable module  100  is secured to temperature calculating unit  200  by aligning the rails  270  and  272  of the temperature calculating unit  200  and the tracks  170  and  172  of the removable module  100 . Once aligned the practitioner slides the removable module  100  downward such that the bottom of the module  100  rests on mounting surface  240  and securing means  242  and  244  mate with recesses  142  and  144  until locking tab  166  snaps into place. This attaching process is best shown in FIG. 2. When secured in this manner, first connector component  120  and second connector component  220  form the connection to activate the thermometer  10 .  
         [0050]    The temperature sensitive probe  161  is removed from the isolation chamber  140 , activating the thermometer to ready mode. Probe  161  is then inserted into a probe cover  184  within storage chamber  182 . Insertion of the probe  161  into the probe cover  184  creates a snap fit between the probe  161  and probe cover  184 . The probe  161  is withdrawn from the carton  186  with cover  184  attached. The practitioner pushes button  284 , shown on FIG. 1, to select the oral or axillary mode. A short beep indicates that the thermometer  10  is ready to take a measurement. Probe  161  is inserted into the patient&#39;s mouth. When the measurement is complete a long beep is sounded and the final temperature reading  280  is displayed. Temperature reading  280  is observed through display window  282 . The probe  161  is withdrawn from the patient&#39;s mouth. Button  168  is then depressed to eject the probe cover  184  into a bio waste container, which is then disposed according to current medical practices or local regulations regarding disposal of infectious, biological waste. Probe  161  may then be inserted into another probe cover  184  in carton  186  again if another reading is desired. Alternatively, probe  161  is inserted back into the isolation chamber  140  for storage. The insertion of the probe  161  into the isolation chamber  140  switches the thermometer  10  to standby mode.  
         [0051]    If a rectal temperature measurement is next desired, it is necessary only to change the removable module  100 . To remove the oral module  100 , the practitioner first pulls back on the locking tab  166 . Once the tab  166  is released, the practitioner slides the module  100  off of rails  270  and  272  to disengage the module from the temperature calculating unit  200 . The rectal module  100  is then secured to temperature calculating unit  200  in the manner described above.  
         [0052]    In the embodiment described, then, the probe, the isolation chamber, and the probe covers are contained within one unit, the removable module. This removable module prevents the interchangeable use of the probe, the isolation chambers for storage, and probe covers. Thus the removable module of the current invention reduces all major sources of contamination by preventing the commingling of the probe, the isolation chamber, and the disposable probe covers. At the same time the thermometer unit of the current invention remains cost effective since it requires only one temperature calculating unit to use with all types of probes.  
         [0053]    It is to be understood that the described embodiments of the invention are illustrative only, and that modifications thereof may occur to those skilled in the art: Accordingly, this invention is not to be regarded as limited to the embodiments disclosed, but is to be limited only as defined by the appended claims.