PRIORITY DOCUMENTS

[0001 ] The present application claims priority from Australian Provisional Patent Application No. 2017900631 titled "TEMPERATURE SENSOR" and filed on 24 February 2017, the content of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates to the measurement of the core temperature of an object. In a particular form, the present disclosure relates to the measurement of core temperature of a living organism.

BACKGROUND

[0003] Physiological human core temperature (T _core ) lies between 36.5°C and 37.5°C and values below 36.0°C or above 38.0°C suggest inadequate thermoregulation. Considerable deviation from normal core temperature, particularly in the brain or the intestine, can have life threatening repercussions. Reliable continuous core temperature measurement is important especially in high-risk patients, such as patients undergoing surgery, intensive care unit (1CU) patients, and those highly susceptible to infections due to compromised immune systems due to treatments such as chemotherapy and the like.

[0004] Abnormal T _core can also indicate illness at an early stage and guide appropriate treatment. In addition, controlled T _core manipulation may be used during surgery or as a therapeutic intervention. As an example, mild therapeutic hypothermia is thought to improve the outcome of cardiac arrest and ischemic insult to the brain. Accordingly, reliable T _core measurement is of major importance for monitoring patients in many medical situations.

[0005] Two measurements are accepted as gold standard for determining T _core . The first is measurement of the central blood temperature using a Schwan-Ganz catheter in the pulmonary artery and the second is measurement of the oesophageal temperature using the same catheter arrangement. However, these intravascular catheter thermometers are generally not suitable in most medical situations due to their highly invasive nature. Alternative external, and less accurate, measurement sites include tympanic (ear), axial (underarm), rectal and under the tongue, these sites all being presently used for body temperature measurement. However, placement of the thermometer probe in these sites can cause discomfort to the patient and is unsatisfactory for long-term use, especially in awake patients. Furthermore, these measurements can induce complications. [0006] The direct measurement of body core temperature from the skin surface has, as a result, been considered a desirable method for some time. One of the major problems encountered in non-invasive measurements of core body temperature is related to the thermal properties of the skin. The thermal conductivity of the skin is generally poor and is strongly influenced by the skin blood flow and ambient environment temperatures. The most widely used technique to determine heat loss from the skin is thermal insulation. If an ideal thermal insulating pad is applied to the skin surface, heat loss from this area will be reduced to zero, and after a while the skin surface temperature beneath the pad will be in equilibrium with the deep tissue temperature. However, there are issues with this approach as the theoretical assumption of a 100% heat insulating material being used for the insulating pad is not realised in practice resulting in a failure to create the required adiabatic surface. Accordingly, there is a need for an alternative type of temperature sensor that is capable of conveniently measuring core temperature that may be applied externally to the patient.

SUMMARY

[0007] In a first aspect the present disclosure provides a temperature sensor for measuring a core temperature of an object, including:

a first temperature sensing element configured for placement in thermal contact with the object; a second temperature sensing element spaced from the object and the first temperature sensing element, wherein the first and second temperature sensing elements are separated by a first thermal insulator region having a first temperature dependent thermal resistance R ₁ ;

a third temperature sensing element configured for placement in thermal contact with the object; a fourth temperature sensing element spaced from the object and the third temperature sensing element, wherein the third and fourth temperature sensing elements are separated by a second thermal insulator region having a second temperature dependent thermal conductivity R ₂ ; and

a fifth temperature sensing element located to measure an ambient temperature T ₀ .

[0008] In another form, the first and second temperature sensing elements and the first thermal insulator region form a first heat flow arrangement for conducting heat from a core region of the object.

[0009] In another form, the first heat flow arrangement includes a first heat sink region to promote heat flow in the first heat flow arrangement.

[0010] In another form, the first heat sink region is in thermal contact with the second temperature sensing element. [001 1 ] In another form, the second and third temperature sensing elements and the second thermal insulator region form a second heat flow arrangement for conducting heat from the core region of the object.

[0012] In another form, the second heat flow arrangement includes a second heat sink region to promote heat flow in the second heat flow arrangement.

[0013] In another form, the second heat sink region is in thennal contact with the fourth temperature sensing element.

[0014] In another form, the temperature sensor includes an insulating bamer for thermally isolating the first heat flow arrangement and the second heat flow arrangement from each other.

[0015] In another form, the insulating barrier thennally isolates the fifth temperature sensing element from the first and second heat flow arrangement.

[0016] In another form, the second temperature sensing element is located substantially on top of and spaced from the first temperature sensing element.

[0017] The temperature sensor of any one of the preceding claims, wherein the fourth temperature sensing element is located substantially on top of and spaced from the first temperature sensing element.

[0018] In another form, the first thermal insulator region or the second thermal insulator region is formed from a solid material.

[0019] In another form, the first thermal insulator region and the second thermal insulator region are formed from a solid material.

[0020] In another form, the first thermal insulator region and the second thennal insulator region are formed from the same solid material.

[0021 ] In another form, the first and/or third temperature sensing element are in physical contact with the object.

[0022] In another form, the temperature sensor is configured to measure the core body temperature of a living organism.

[0023] In another form, the temperature sensor includes a flexible base portion for placement on the living organism. [0024] In another form, the temperature sensor includes an adhesive portion for attachment to the living organism.

[0025] In another form, the temperature sensor is configured for use for humans.

[ 0026] In a second aspect, the present disclosure provides a temperature sensing system including: the temperature sensor of the first aspect; and

a data processor to detennine the core temperature of the object based on the temperatures T ₁ , T ₂ , T ₃ , T ₄ and T ₀ measured by first, second, third, fourth and fifth temperature sensing elements respectively.

[0027] In another form, the data processor determines a ratio K(T ₀ )of the thermal resistances and R ₂ based on the measured ambient temperature T ₀ .

[0028] In another form, the data processor determines the core temperature T _core based on the relationship:

[0029] In another form, where the first and second insulator regions are equivalent but only vary in height the data processor determines the core temperature T _core based on the relationship:

[0030] In another form, the processor unit is located remotely from the temperature sensor. [0031 ] In another form, the processor unit communicates wirelessly with the temperature sensor.

[0032] In another form, the processor unit is integrated with the temperature sensor.

BRIEF DESCRIPTION OF DRAWINGS

[0033 ] Embodiments of the present disclosure will be discussed with reference to the accompanying drawings wherein:

[0034] Figure 1 is a figurative overview diagram of a temperature sensor for measuring the core temperature of an object in accordance with an illustrative embodiment; [0035] Figure 2 is a top perspective view of a temperature sensor for measuring the core temperature of a living organism in accordance with an illustrative embodiment;

[0036] Figure 3 is an exploded view of the temperature sensor illustrated in Figure 2;

[0037] Figure 4 is a side sectional view of the temperature sensor illustrated in Figure 2;

[0038] Figures 5A to 5C are example temperature sensing systems based on the temperature sensor illustrated in Figures 2 to 4;

[0039] Figure 6 is a side view of the insulator blocks illustrated in Figures 2 to 4 depicting relevant dimensions;

[0040] Figure 7 is a graph of K(T ₀ ) as a function of T ₀ for the insulator block configuration illustrated in Figure 6;

[0041 ] Figure 8 is a figurative overview diagram of a temperature sensor set up illustrating the various physical parameters;

[ 0042] Figure 9 is an exploded view of a temperature sensor in accordance with another illustrative embodiment; and

[0043] Figure 10 is a side sectional view of the temperature sensor illustrated in Figure 9.

[0044] In the following description, like reference characters designate like or corresponding parts throughout the figures.

DESCRIPTION OF EMBODIMENTS

[ 0045 ] Referring now to Figure 1 , there is shown a figurative overview diagram of a temperature sensor 100 for measuring the core temperature of an object 200 according to an illustrative embodiment.

Temperature sensor 100 includes in this embodiment a temperature sensing arrangement consisting of first temperature sensing element 121 , second temperature sensing element 122, third temperature sensing element 123, fourth temperature sensing element 124 and fifth temperature sensing element 125. In this example, first and third temperature sensing elements 121, 123 are both configured for placement in thermal contact with the surface of the object 200. As would be appreciated, this does not require sensing elements 121 , 123 to be in physical contact with the object and in this case a high thermally conductive metallic disc 140 is employed to sample a larger surface area of the object 200. [0046] Second temperature sensing element 122 is positioned so that it is spaced from the object 200 and the first temperature sensing element 121 by a first thermal insulator region 13 1 having a first thermal resistance and forms a first heat flow arrangement that conducts heat from a core region of the object having the core temperature. Similarly, fourth temperature sensing element 124 is positioned so that it is spaced from the object 200 and the third temperature sensing element 123 by a second thermal insulator region 132 having a first thermal resistance R ₂ and forms a second heat flow arrangement that conducts heat from the core region of the object.

[0047] In this illustrative embodiment, first and second thermal insulator regions 131 , 132 are shown as comprising a solid material or insulator block but as would be appreciated, these regions may be provided by a suitable air gap or the like. The fifth temperature sensing element 125 is located to measure the ambient temperature remote from object 200. In this example, temperature sensor 100 further includes a housing 130 comprising a highly insulating material that thermally isolates first thermal insulator region 13 1 and associated first and second temperature sensing elements 121 , 122 from second thermal insulator region 132 and associated third and fourth temperature sensing elements 123, 124.

[0048] For a heat source T _core (eg, deep tissue temperature of body) covered by a thermal insulator (eg, skin & subcutaneous tissue), the heat flow / through the thermal insulator may be calculated by the following equation assuming there is a constant and vertical heat flow from the heat source T _core to the surface of the thermal insulator:

where R _s is the thermal resistance of the thermal insulator corresponding to object 200 (eg, skin and hypodermic tissue) and T _s is the temperature at the surface of the thermal insulator (eg, skin surface).

[0049] Considering a second thermal insulator placed at the surface boundary of the first insulator (eg, skin surface) and where the temperature reaches equilibrium, the heat flow from the heat source (deep body) through the first insulator to the boundary (skin surface) and the heat flow from the boundary of the first insulator boundary (skin surface) through the second insulator will balance and equalise. Combining the heat flow through the two thermal insulators then gives the following relationship:

where T _u is the temperature at the external boundary of the second insulator and R _u is the thermal resistance of the second insulator.

[0050] This equation can then be rearranged for T _core to give:

[0051 ] In the case of measuring core body temperature of a human or an animal , the above

Tcore relationship, however, requires the knowledge of the thermal resistance value R _s of the skin and hypodermic tissue. Unfortunately, this cannot be accurately measured and is significantly influenced by the varying hypodermic blood flow.

[0052 ] Referring again to Figure 1 , when two thermal insulators with different thermal resistance R _t and R ₂ are positioned on the surface of the object (eg, skin surface) and located proximate to each other, the equivalent T _core equations are as follows:

where Τ ₁ and T ₃ are the object temperatures below the two thermal insulator regions 131 , 132 at the surface of the object as measured by first and third temperature sensing elements 121 , 123, and T ₂ and T ₄ are the temperatures at the upper surface boundary of each of the thermal insulator regions 131 , 132 as measured by second and fourth temperature sensing elements 122, 124.

[0053] When the two thermal insulator regions 131, 132 are positioned proximate to each other, the values for the thermal resistance of the object (ie, R _s ,) at the two different locations are very nearly the same and may be eliminated from the above equations to derive the following equation which is independent of R _s :

where K is defined to be the ratio of the thermal resistances, R ₁ /R ₂ .

[0054] As would be appreciated, both R^ and R ₂ vary as a function of the ambient temperature T ₀ surrounding the thermal insulator regions 131 , 132 as measured by the fifth temperature sensing element 125, which to a good approximation will be equivalent, and hence K will also vary as a function of ambient temperature. The function K(T _Q ) may be determined experimentally through measuring the thermal resistances R ₁ and R ₂ over an operating temperature range. In this manner, T _core may be determined without having to determine the thermal resistance of the object. [0055] Referring now to Figures 2 to 4, there are shown various views of a temperature sensor 200 for measuring the core temperature of a living organism 300 such as a human or animal according to a second illustrative embodiment. Temperature sensor 200 includes a flexible base or substrate portion 260 formed of polyurethane rubber having an underside adhesive portion 261 for attachment to the skin. In this example, base portion 260 is formed having a straight sided oval configuration includes two circular shaped cut-out portions 262 located either side of base portion 260 and each shaped to receive a thermal conductive annulus or ring member 240 which receives in its central aperture the respective temperature sensing element as will be described below. Ring member 240 not only enhances temperature conduction but also assists in reducing the effects of radiant heat transfer to provide a homogeneous temperature at the respective sensor sites.

[0056] Similar to the temperature sensor 100 described with respect to Figure 1 , temperature sensor 200 incorporates a temperature sensing arrangement consisting of first temperature sensing element 221 , second temperature sensing element 222, third temperature sensing element 223, fourth temperature sensing element 224 and fifth temperature sensing element 225. In this embodiment, the temperature sensing elements are negative temperature coefficient (NTC) thermistors but as would be appreciated these sensing elements may be any thermosensitive device including, but not limited to, positive temperature coefficient (PTC) thermistors, resistance temperature detectors (RTD), thermocouples, silicone bandgap temperature sensors or crystal temperature sensors.

[0057] First and third temperature sensing elements 221 , 223 are located in their respective thermal conductive ring members 240 and this assembly then resides in the respective cut-out portion 262 of the flexible base portion 260. In this manner, first and third temperature sensing elements 221 , 223 will be in direct physical contact with the skin once temperature sensor 200 has been attached. Situated above, and in thermal contact with, the first and third temperature sensing elements 221, 223 are respective insulator blocks 231 , 232, which in this embodiment are formed as a cylindrically shaped body of material such as foam, silicone, rubber,plastic or equivalent material having a well behaved thermal resistance as a function of temperature. Other examples of suitable materials include, but are not limited to, aluminium (or other metals), polytetrafluoroethylene (PTFE) or nylon.

[0058] In this example embodiment, thermal insulator regions in the form of insulator blocks 231 , 232 are formed of the same material but have different nominal thermal resistances R ₁ and R ₂ due to their size. In another embodiment, insulator blocks 231 , 232 may be of the same size but formed from different material hence providing differing nominal thermal resistances R^ and R ₂ .

[ 0059] Located on the top of the insulator blocks 23 1 , 232 are respective second and fourth temperature sensing elements 222, 224 and thermally conductive ring member 240 assemblies which assist in thermally coupling the sensing elements 222, 224 to the respective insulator blocks 231, 232 and which further function to provide respective heat sink regions to promote the flow of heat through the respective insulator blocks 23 1, 232.

[0060] In this configuration, second temperature sensing element 222 is spaced from first temperature sensing element 221 and the surface of the skin with the first and second temperature sensing elements 221, 222 separated by insulator block 23 1. Similarly, fourth temperature sensing element 224 is spaced from third temperature sensing element 223 and the surface of the skin with the first and second temperature sensing elements 224, 223 separated by insulator block 232. In this embodiment, the second and fourth temperature sensing element 222, 224 are located substantially on top of and spaced from the first and third temperature sensing elements 221, 223 respectively.

[0061 ] Surrounding insulator blocks 231 , 232 is an insulating barrier 250 having two cylindrical shaped receiving areas 251 , 252 which are sized and shaped to isolate each insulator block and the associated temperature sensing elements from each other. Insulating barrier 250 is formed from a material having a high relative thermal resistivity relative to insulator blocks 23 1 , 232 and is configured to be attached to flexible base portion 260. In one example embodiment, where the insulator blocks 231, 232 are formed from aluminium, the insulating barrier 250 is formed from silicone.

[00621 In another illustrative embodiment, where the insulator blocks 23 1 , 232 are formed from silicone, the insulating barrier 250 is formed from cellular polyurethane foam. Fifth temperature sensing element 225 is located external to insulating barrier 250 and measures the ambient temperature. Temperature sensor 200 further includes a protective housing or casing 230 that attaches to a stepped recessed region 263 in the base portion 260 to form the sensor package.

[0063] Temperature sensor 200 in this embodiment is formed having a layered structure. The first layer consists of the first and third temperature sensing elements 221, 223 which are in thermal contact with the skin. The second layer consists of the thermal insulator regions or insulator blocks 231 , 232 and the third layer consists of the second and fourth temperature sensing elements 222, 224. The fifth layer consists of the fifth temperature sensing element 225 and housing 230. As would be appreciated, this layered structure or assembly facilitates manufacturing and each of the layers may be made of appropriate materials and sealed with respect to each other making the device especially suitable for medical applications. In addition, the layers may be formed of flexible material to conform with the region whose core temperature is being measured. In one example embodiment, temperature sensor may be sealed to provide water resistance.

[0064] Temperature sensor 200 further includes an integrated power supply and processing electronics 290 comprising an analogue to digital converter to convert the analogue signal from each of the temperature sensing elements to a temperature value for further processing. In this example, temperature sensor 200 further includes a wireless transmission module 295 for transmission of the temperature values for each of the five temperature sensing elements to a data processing unit for determining the core temperature based on the relationship for T _core described above and together forming a temperature sensing system. Temperature sensor 200 may be configured as a disposable single use unit or be rechargeable.

[0065] Referring now to Figures 5A to 5C, there shown example temperature sensing systems for distributing the data gathering, transmission and processing functionality based on temperature sensor 200. In Figure 5A, temperature sensing system includes temperature sensor 200 which sends data by wireless transmission module 295 to smart phone 510 or personal computer 520 or equivalent by a wireless transmission interface. In this embodiment, the data may be temperature values and the smart phone 510 or personal computer 520 then functions as a data processor to process these values to determine core temperature. In another embodiment, the data sent from temperature sensor relates to raw digitised values from each of the temperature sensing elements which are then further processed to provide temperature values for each of the temperature sensing elements which are then further processed to determine core temperature.

[0066] As would be appreciated, the wireless transmission interface may comprise a network interface and/or communications module for communicating with an equivalent communications module in another device using a predefined communications protocol (eg Bluetooth, Zigbee, NFC, ANT & ANT+, IEEE 802.15, IEEE 802. 1 1 , TCP/IP, UDP, etc) and may transmit the wireless signals by one or more intermediate routers or similar wireless transmission devices.

[0067] Referring now to Figure 5B, there is shown another example temperature sensing system involving wireless transmission of temperature sensor data to the "cloud" where it is then stored and processed to determine core temperature and where it may then be further accessed by a smart phone 510 or personal computer 520 or equivalent acting in this sense as a "dumb" terminal to display the core temperature data. In another example, the raw digitised data from temperature sensing elements is stored in the cloud where it then may be accessed by a smart phone 510 or personal computer 520 for further processing.

[0068] Referring now to Figure 5C, there is shown yet another example temperature sensing system where temperature sensor 200 contains all relevant processing electronics for determining core temperature and an integrated display 296 for display of the core temperature. In other embodiments, temperature sensor 200 may include a physical network interface and be physically connected by wired means to transmit data for further processing or display by a separate data processor. [0069] In yet another embodiment, the temperature data includes a unique identifier and is sent either wirelessly or by wired transmission to enterprise level patient monitoring software responsible for monitoring the health status of a number of patients in a medical facility.

[0070] Referring now to Figure 7, there is shown a graph of the empirically determined function K(T _Q ) as a function of T _Q for the insulator block configuration illustrated in Figure 6. As would be appreciated, the graph in Figure 7 may be implemented as a lookup table in order to determine K(T ₀ ) for any measured T ₀ which is then used in the determination of T _core . In another embodiment, a function such as a spline function is fitted to provide an analytic formula for K(T _Q ) which the measured T _Q may be substituted into.

[0071 ] Temperature sensor 200 would be typically applied to the torso or upper thoracic region of the body but may also be applied to the head and other regions as required. For example, other regions may include, but not be limited to, placement of sensor 200 over the heart, sternum or liver depending on requirements. As would be appreciated, flexible base portion 260 with its adhesive underlay 261 allows the sensor 200 to conform and follow the contours of the body surface. In one illustrative embodiment, temperature sensor 200 may be one of the biological sensors forming part of a wearable intravenous fluid delivery system such as the one described in PCT Publication No WO 2015/03 1938 A l , filed 3

September 2014 by the Applicant and titled "Wearable Intravenous Fluid Delivery System", the contents of which are incorporated by reference in this specification in their entirety.

[0072] Referring now to Figure 8, there is shown a figurative view of a temperature sensor set up indicating the various physical parameters employed for determining an alternative derivation of T _core based on a configuration where the thermal insulator regions are equivalent but only vary in height. Based on the sensor set up illustrated in Figure 8, the following parameters may be defined:

• V _b = temperature difference from T _core to top boundary of thermal insulator region 1, ie. T _core — T ₂ .

• V _\ = temperature difference through thermal insulator region 1 , ie, (T ₁ — T ₂ ).

• V ₂ = temperature difference through thermal insulator region 2, ie, (T ₃ —T ₄ ).

• V _s = temperature difference from core to skin surface, ie, (T _core —T ₃ ).

• V _d = temperature difference form top of thermal insulator 2 to top of thermal insulator region 1 , ie, (T ₄ - T ₂ ).

• R _s = thermal resistance of the skin and subcutaneous tissue.

• R- _i = thermal resistance of thermal insulator region 1.

• R ₂ = thermal resistance of thermal insulator region 2.

[ 0073] It follows that:

where K is again defined to be the ratio of the thermal resistances, R ₁ /R ₂ .

[0077] Referring now to Figures 9 and 10, there is shown side sectional and exploded views of a temperature sensor 400 according to another illustrative embodiment. As can be seen from inspection, Figure 9 shows an equivalent exploded view to that of Figure 3 and Figure 10 shows an equivalent sectional view to that of Figure 4, where Figures 3 and 4 are directed to temperature sensor 200.

[0078] In this illustrative embodiment, temperature sensor 400 includes an insulating barrier 450 comprising an air gap 458 surrounding each of the thermal insulator regions or insulator blocks 231 , 232. In this example, the air gap 458 is formed as an annular cylinder resulting from configuring the two cylindrical shaped receiving members 451 , 452 to have an inner diameter greater than the outer diameter of each of the insulator blocks 231 , 232. Insulating barrier 450 further includes two circular shaped apertures 453, 454 as best seen in Figure 9 which are located centrally on the top or roof of the respective receiving regions 451 , 452 and which each receive the thermally conductive ring member 440 and temperature sensing element 222, 224 assemblies.

[0079] In this manner, the conductive ring member 440 and temperature sensing element 222, 224 assemblies are exposed as compared to sensor 200 which as a result generally provides an initially larger temperature differential between the skin surface and the "exposed" temperature sensing elements 222, 224 promoting the flow of heat vertical ly or axially through insulator blocks 231 , 232 as they are not insulated from the ambient environment. In this example, the conductive ring members 440 have a greater surface area as compared to ring members 240 providing an enhanced heat sink region that further promotes the flow of heat vertically or axially through insulator blocks 23 1 , 232.

[0080] Because of the larger diameter of the cylindrically shaped receiving members 451 , 452 of the insulating barrier 450 of sensor 400 as compared to sensor 200, the stepped recessed region 463 in the base portion 260 is correspondingly modified to receive this increased diameter and further the circular shaped cut-out portions 462 located either side of base portion 260 have a larger diameter to receive the larger diameter thermal conductive annulus or ring members 240 and their associated respective temperature sensing elements.

[0081 ] As would be appreciated, and as shown in Figure 10, temperature sensor also includes a housing 230 and the fifth temperature sensing element 225 and in one example, temperature sensing element 225 is attached to the outer surface of housing 230. In another example, also shown in Figure 10 as an alternative, temperature sensing element 225 is attached to the flexible base portion 260.

[0082] As would also be appreciated, the parameter K(T ₀ ) which varies as a function of TO will depend on the configuration of the temperature sensor including the size, type and configuration of the insulator blocks and the size, type and configuration of the insulating barrier. Depending on the design

requirements of the sensor, the configuration may be selected so that the behaviour K(T _Q ) is optimally characterised over a selected range of ambient temperature of interest. In one example, the configuration may be selected so that the variation in K(T ₀ ) is minimised over a selected range of ambient temperature. In another example, the configuration is selected so that the variation in K(T ₀ ) as a function of T ₀ is substantially linear over a selected range of ambient temperature.

[0083] The above described embodiments provide a temperature sensor and sensing system that may be applied externally to the object and in the case of a human patient may be adhered to the skin directly without the need for any invasive procedures or the intrusion of thermometers into a selected body cavity or orifice. This can allow for convenient continuous monitoring of core temperature.

[0084] The temperature sensing system may also be configured to track temperature trends over extended periods to enable detection of a change in patient health. In one example, the temperature sensing system captures the patient temperature over a 24 hour period to determine the patient's temperature circadian cycle as a baseline for health monitoring. In this manner, small changes from the expected temperature at a particular time in the cycle may be detected and an alert generated based on any discrepancy. [0085] In one example, the data processor implements a machine learning algorithm to recognise these changes in temperature trends based on changes from the baseline temperature variation of a patient. Depending on the severity of the change, the system may then generate an alert signal to the patient and/or to the healthcare professional. As would be appreciated, the temperature sensor may be combined with additional biometric sensors such as heart rate, respiration or blood oxygen monitors to provide combined monitoring of a patient's condition. In one example, a combined temperature, heart rate, respiration and blood oxygen sensor may be placed on the chest to monitor vital signs from the one region.

[0086] Those of skill in the art would appreciate that the various illustrative logical blocks, modules, circuits, and method steps described in connection with the embodiments disclosed above may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Accordingly, embodiments may be implemented to achieve the described functionality in varying ways for each particular application.

[0087] Throughout the specification and the claims that follow, unless the context requires otherwise, the words "comprise" and "include" and variations such as "comprising" and "including" will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

[0088] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge.

[0089] It will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular application described. Neither is the present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the invention is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention as set forth and defined by the following claims.